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Jack Grigg
2018-08-28 23:03:42 +01:00
parent ad16ba6a35 09b6e6f921
commit e924247e73
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# BLS12-381
This is an implementation of the BLS12-381 pairing-friendly elliptic curve construction.
## BLS12 Parameterization
BLS12 curves are parameterized by a value *x* such that the base field modulus *q* and subgroup *r* can be computed by:
* q = (x - 1)<sup>2</sup> ((x<sup>4</sup> - x<sup>2</sup> + 1) / 3) + x
* r = (x<sup>4</sup> - x<sup>2</sup> + 1)
Given primes *q* and *r* parameterized as above, we can easily construct an elliptic curve over the prime field F<sub>*q*</sub> which contains a subgroup of order *r* such that *r* | (*q*<sup>12</sup> - 1), giving it an embedding degree of 12. Instantiating its sextic twist over an extension field F<sub>q<sup>2</sup></sub> gives rise to an efficient bilinear pairing function between elements of the order *r* subgroups of either curves, into an order *r* multiplicative subgroup of F<sub>q<sup>12</sup></sub>.
In zk-SNARK schemes, we require F<sub>r</sub> with large 2<sup>n</sup> roots of unity for performing efficient fast-fourier transforms. As such, guaranteeing that large 2<sup>n</sup> | (r - 1), or equivalently that *x* has a large 2<sup>n</sup> factor, gives rise to BLS12 curves suitable for zk-SNARKs.
Due to recent research, it is estimated by many that *q* should be approximately 384 bits to target 128-bit security. Conveniently, *r* is approximately 256 bits when *q* is approximately 384 bits, making BLS12 curves ideal for 128-bit security. It also makes them ideal for many zk-SNARK applications, as the scalar field can be used for keying material such as embedded curve constructions.
Many curves match our descriptions, but we require some extra properties for efficiency purposes:
* *q* should be smaller than 2<sup>383</sup>, and *r* should be smaller than 2<sup>255</sup>, so that the most significant bit is unset when using 64-bit or 32-bit limbs. This allows for cheap reductions.
* F<sub>q<sup>12</sup></sub> is typically constructed using towers of extension fields. As a byproduct of [research](https://eprint.iacr.org/2011/465.pdf) for BLS curves of embedding degree 24, we can identify subfamilies of BLS12 curves (for our purposes, where x mod 72 = {16, 64}) that produce efficient extension field towers and twisting isomorphisms.
* We desire *x* of small Hamming weight, to increase the performance of the pairing function.
## BLS12-381 Instantiation
The BLS12-381 construction is instantiated by `x = -0xd201000000010000`, which produces the largest `q` and smallest Hamming weight of `x` that meets the above requirements. This produces:
* q = `0x1a0111ea397fe69a4b1ba7b6434bacd764774b84f38512bf6730d2a0f6b0f6241eabfffeb153ffffb9feffffffffaaab` (381 bits)
* r = `0x73eda753299d7d483339d80809a1d80553bda402fffe5bfeffffffff00000001` (255 bits)
Our extension field tower is constructed as follows:
1. F<sub>q<sup>2</sup></sub> is constructed as F<sub>q</sub>(u) / (u<sup>2</sup> - β) where β = -1.
2. F<sub>q<sup>6</sup></sub> is constructed as F<sub>q<sup>2</sup></sub>(v) / (v<sup>3</sup> - ξ) where ξ = u + 1
3. F<sub>q<sup>12</sup></sub> is constructed as F<sub>q<sup>6</sup></sub>(w) / (w<sup>2</sup> - γ) where γ = v
Now, we instantiate the elliptic curve E(F<sub>q</sub>) : y<sup>2</sup> = x<sup>3</sup> + 4, and the elliptic curve E'(F<sub>q<sup>2</sup></sub>) : y<sup>2</sup> = x<sup>3</sup> + 4(u + 1).
The group G<sub>1</sub> is the *r* order subgroup of E, which has cofactor (x - 1)<sup>2</sup> / 3. The group G<sub>2</sub> is the *r* order subgroup of E', which has cofactor (x<sup>8</sup> - 4x<sup>7</sup> + 5x<sup>6</sup> - 4x<sup>4</sup> + 6x<sup>3</sup> - 4x<sup>2</sup> - 4x + 13) / 9.
### Generators
The generators of G<sub>1</sub> and G<sub>2</sub> are computed by finding the lexicographically smallest valid `x`-coordinate, and its lexicographically smallest `y`-coordinate and scaling it by the cofactor such that the result is not the point at infinity.
#### G1
```
x = 3685416753713387016781088315183077757961620795782546409894578378688607592378376318836054947676345821548104185464507
y = 1339506544944476473020471379941921221584933875938349620426543736416511423956333506472724655353366534992391756441569
```
#### G2
```
x = 3059144344244213709971259814753781636986470325476647558659373206291635324768958432433509563104347017837885763365758*u + 352701069587466618187139116011060144890029952792775240219908644239793785735715026873347600343865175952761926303160
y = 927553665492332455747201965776037880757740193453592970025027978793976877002675564980949289727957565575433344219582*u + 1985150602287291935568054521177171638300868978215655730859378665066344726373823718423869104263333984641494340347905
```
### Serialization
* Fq elements are encoded in big-endian form. They occupy 48 bytes in this form.
* Fq2 elements are encoded in big-endian form, meaning that the Fq element c0 + c1 * u is represented by the Fq element c1 followed by the Fq element c0. This means Fq2 elements occupy 96 bytes in this form.
* The group G1 uses Fq elements for coordinates. The group G2 uses Fq2 elements for coordinates.
* G1 and G2 elements can be encoded in uncompressed form (the x-coordinate followed by the y-coordinate) or in compressed form (just the x-coordinate). G1 elements occupy 96 bytes in uncompressed form, and 48 bytes in compressed form. G2 elements occupy 192 bytes in uncompressed form, and 96 bytes in compressed form.
The most-significant three bits of a G1 or G2 encoding should be masked away before the coordinate(s) are interpreted. These bits are used to unambiguously represent the underlying element:
* The most significant bit, when set, indicates that the point is in compressed form. Otherwise, the point is in uncompressed form.
* The second-most significant bit indicates that the point is at infinity. If this bit is set, the remaining bits of the group element's encoding should be set to zero.
* The third-most significant bit is set if (and only if) this point is in compressed form _and_ it is not the point at infinity _and_ its y-coordinate is the lexicographically largest of the two associated with the encoded x-coordinate.

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use super::fq::FROBENIUS_COEFF_FQ12_C1;
use super::fq2::Fq2;
use super::fq6::Fq6;
use rand::{Rand, Rng};
use Field;
/// An element of Fq12, represented by c0 + c1 * w.
#[derive(Copy, Clone, Debug, Eq, PartialEq)]
pub struct Fq12 {
pub c0: Fq6,
pub c1: Fq6,
}
impl ::std::fmt::Display for Fq12 {
fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
write!(f, "Fq12({} + {} * w)", self.c0, self.c1)
}
}
impl Rand for Fq12 {
fn rand<R: Rng>(rng: &mut R) -> Self {
Fq12 {
c0: rng.gen(),
c1: rng.gen(),
}
}
}
impl Fq12 {
pub fn conjugate(&mut self) {
self.c1.negate();
}
pub fn mul_by_014(&mut self, c0: &Fq2, c1: &Fq2, c4: &Fq2) {
let mut aa = self.c0;
aa.mul_by_01(c0, c1);
let mut bb = self.c1;
bb.mul_by_1(c4);
let mut o = *c1;
o.add_assign(c4);
self.c1.add_assign(&self.c0);
self.c1.mul_by_01(c0, &o);
self.c1.sub_assign(&aa);
self.c1.sub_assign(&bb);
self.c0 = bb;
self.c0.mul_by_nonresidue();
self.c0.add_assign(&aa);
}
}
impl Field for Fq12 {
fn zero() -> Self {
Fq12 {
c0: Fq6::zero(),
c1: Fq6::zero(),
}
}
fn one() -> Self {
Fq12 {
c0: Fq6::one(),
c1: Fq6::zero(),
}
}
fn is_zero(&self) -> bool {
self.c0.is_zero() && self.c1.is_zero()
}
fn double(&mut self) {
self.c0.double();
self.c1.double();
}
fn negate(&mut self) {
self.c0.negate();
self.c1.negate();
}
fn add_assign(&mut self, other: &Self) {
self.c0.add_assign(&other.c0);
self.c1.add_assign(&other.c1);
}
fn sub_assign(&mut self, other: &Self) {
self.c0.sub_assign(&other.c0);
self.c1.sub_assign(&other.c1);
}
fn frobenius_map(&mut self, power: usize) {
self.c0.frobenius_map(power);
self.c1.frobenius_map(power);
self.c1.c0.mul_assign(&FROBENIUS_COEFF_FQ12_C1[power % 12]);
self.c1.c1.mul_assign(&FROBENIUS_COEFF_FQ12_C1[power % 12]);
self.c1.c2.mul_assign(&FROBENIUS_COEFF_FQ12_C1[power % 12]);
}
fn square(&mut self) {
let mut ab = self.c0;
ab.mul_assign(&self.c1);
let mut c0c1 = self.c0;
c0c1.add_assign(&self.c1);
let mut c0 = self.c1;
c0.mul_by_nonresidue();
c0.add_assign(&self.c0);
c0.mul_assign(&c0c1);
c0.sub_assign(&ab);
self.c1 = ab;
self.c1.add_assign(&ab);
ab.mul_by_nonresidue();
c0.sub_assign(&ab);
self.c0 = c0;
}
fn mul_assign(&mut self, other: &Self) {
let mut aa = self.c0;
aa.mul_assign(&other.c0);
let mut bb = self.c1;
bb.mul_assign(&other.c1);
let mut o = other.c0;
o.add_assign(&other.c1);
self.c1.add_assign(&self.c0);
self.c1.mul_assign(&o);
self.c1.sub_assign(&aa);
self.c1.sub_assign(&bb);
self.c0 = bb;
self.c0.mul_by_nonresidue();
self.c0.add_assign(&aa);
}
fn inverse(&self) -> Option<Self> {
let mut c0s = self.c0;
c0s.square();
let mut c1s = self.c1;
c1s.square();
c1s.mul_by_nonresidue();
c0s.sub_assign(&c1s);
c0s.inverse().map(|t| {
let mut tmp = Fq12 { c0: t, c1: t };
tmp.c0.mul_assign(&self.c0);
tmp.c1.mul_assign(&self.c1);
tmp.c1.negate();
tmp
})
}
}
#[cfg(test)]
use rand::{SeedableRng, XorShiftRng};
#[test]
fn test_fq12_mul_by_014() {
let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
for _ in 0..1000 {
let c0 = Fq2::rand(&mut rng);
let c1 = Fq2::rand(&mut rng);
let c5 = Fq2::rand(&mut rng);
let mut a = Fq12::rand(&mut rng);
let mut b = a;
a.mul_by_014(&c0, &c1, &c5);
b.mul_assign(&Fq12 {
c0: Fq6 {
c0: c0,
c1: c1,
c2: Fq2::zero(),
},
c1: Fq6 {
c0: Fq2::zero(),
c1: c5,
c2: Fq2::zero(),
},
});
assert_eq!(a, b);
}
}
#[test]
fn fq12_field_tests() {
use PrimeField;
::tests::field::random_field_tests::<Fq12>();
::tests::field::random_frobenius_tests::<Fq12, _>(super::fq::Fq::char(), 13);
}

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use super::fq::{FROBENIUS_COEFF_FQ2_C1, Fq, NEGATIVE_ONE};
use rand::{Rand, Rng};
use {Field, SqrtField};
use std::cmp::Ordering;
/// An element of Fq2, represented by c0 + c1 * u.
#[derive(Copy, Clone, Debug, Eq, PartialEq)]
pub struct Fq2 {
pub c0: Fq,
pub c1: Fq,
}
impl ::std::fmt::Display for Fq2 {
fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
write!(f, "Fq2({} + {} * u)", self.c0, self.c1)
}
}
/// `Fq2` elements are ordered lexicographically.
impl Ord for Fq2 {
#[inline(always)]
fn cmp(&self, other: &Fq2) -> Ordering {
match self.c1.cmp(&other.c1) {
Ordering::Greater => Ordering::Greater,
Ordering::Less => Ordering::Less,
Ordering::Equal => self.c0.cmp(&other.c0),
}
}
}
impl PartialOrd for Fq2 {
#[inline(always)]
fn partial_cmp(&self, other: &Fq2) -> Option<Ordering> {
Some(self.cmp(other))
}
}
impl Fq2 {
/// Multiply this element by the cubic and quadratic nonresidue 1 + u.
pub fn mul_by_nonresidue(&mut self) {
let t0 = self.c0;
self.c0.sub_assign(&self.c1);
self.c1.add_assign(&t0);
}
/// Norm of Fq2 as extension field in i over Fq
pub fn norm(&self) -> Fq {
let mut t0 = self.c0;
let mut t1 = self.c1;
t0.square();
t1.square();
t1.add_assign(&t0);
t1
}
}
impl Rand for Fq2 {
fn rand<R: Rng>(rng: &mut R) -> Self {
Fq2 {
c0: rng.gen(),
c1: rng.gen(),
}
}
}
impl Field for Fq2 {
fn zero() -> Self {
Fq2 {
c0: Fq::zero(),
c1: Fq::zero(),
}
}
fn one() -> Self {
Fq2 {
c0: Fq::one(),
c1: Fq::zero(),
}
}
fn is_zero(&self) -> bool {
self.c0.is_zero() && self.c1.is_zero()
}
fn square(&mut self) {
let mut ab = self.c0;
ab.mul_assign(&self.c1);
let mut c0c1 = self.c0;
c0c1.add_assign(&self.c1);
let mut c0 = self.c1;
c0.negate();
c0.add_assign(&self.c0);
c0.mul_assign(&c0c1);
c0.sub_assign(&ab);
self.c1 = ab;
self.c1.add_assign(&ab);
c0.add_assign(&ab);
self.c0 = c0;
}
fn double(&mut self) {
self.c0.double();
self.c1.double();
}
fn negate(&mut self) {
self.c0.negate();
self.c1.negate();
}
fn add_assign(&mut self, other: &Self) {
self.c0.add_assign(&other.c0);
self.c1.add_assign(&other.c1);
}
fn sub_assign(&mut self, other: &Self) {
self.c0.sub_assign(&other.c0);
self.c1.sub_assign(&other.c1);
}
fn mul_assign(&mut self, other: &Self) {
let mut aa = self.c0;
aa.mul_assign(&other.c0);
let mut bb = self.c1;
bb.mul_assign(&other.c1);
let mut o = other.c0;
o.add_assign(&other.c1);
self.c1.add_assign(&self.c0);
self.c1.mul_assign(&o);
self.c1.sub_assign(&aa);
self.c1.sub_assign(&bb);
self.c0 = aa;
self.c0.sub_assign(&bb);
}
fn inverse(&self) -> Option<Self> {
let mut t1 = self.c1;
t1.square();
let mut t0 = self.c0;
t0.square();
t0.add_assign(&t1);
t0.inverse().map(|t| {
let mut tmp = Fq2 {
c0: self.c0,
c1: self.c1,
};
tmp.c0.mul_assign(&t);
tmp.c1.mul_assign(&t);
tmp.c1.negate();
tmp
})
}
fn frobenius_map(&mut self, power: usize) {
self.c1.mul_assign(&FROBENIUS_COEFF_FQ2_C1[power % 2]);
}
}
impl SqrtField for Fq2 {
fn legendre(&self) -> ::LegendreSymbol {
self.norm().legendre()
}
fn sqrt(&self) -> Option<Self> {
// Algorithm 9, https://eprint.iacr.org/2012/685.pdf
if self.is_zero() {
Some(Self::zero())
} else {
// a1 = self^((q - 3) / 4)
let mut a1 = self.pow([
0xee7fbfffffffeaaa,
0x7aaffffac54ffff,
0xd9cc34a83dac3d89,
0xd91dd2e13ce144af,
0x92c6e9ed90d2eb35,
0x680447a8e5ff9a6,
]);
let mut alpha = a1;
alpha.square();
alpha.mul_assign(self);
let mut a0 = alpha;
a0.frobenius_map(1);
a0.mul_assign(&alpha);
let neg1 = Fq2 {
c0: NEGATIVE_ONE,
c1: Fq::zero(),
};
if a0 == neg1 {
None
} else {
a1.mul_assign(self);
if alpha == neg1 {
a1.mul_assign(&Fq2 {
c0: Fq::zero(),
c1: Fq::one(),
});
} else {
alpha.add_assign(&Fq2::one());
// alpha = alpha^((q - 1) / 2)
alpha = alpha.pow([
0xdcff7fffffffd555,
0xf55ffff58a9ffff,
0xb39869507b587b12,
0xb23ba5c279c2895f,
0x258dd3db21a5d66b,
0xd0088f51cbff34d,
]);
a1.mul_assign(&alpha);
}
Some(a1)
}
}
}
}
#[test]
fn test_fq2_ordering() {
let mut a = Fq2 {
c0: Fq::zero(),
c1: Fq::zero(),
};
let mut b = a.clone();
assert!(a.cmp(&b) == Ordering::Equal);
b.c0.add_assign(&Fq::one());
assert!(a.cmp(&b) == Ordering::Less);
a.c0.add_assign(&Fq::one());
assert!(a.cmp(&b) == Ordering::Equal);
b.c1.add_assign(&Fq::one());
assert!(a.cmp(&b) == Ordering::Less);
a.c0.add_assign(&Fq::one());
assert!(a.cmp(&b) == Ordering::Less);
a.c1.add_assign(&Fq::one());
assert!(a.cmp(&b) == Ordering::Greater);
b.c0.add_assign(&Fq::one());
assert!(a.cmp(&b) == Ordering::Equal);
}
#[test]
fn test_fq2_basics() {
assert_eq!(
Fq2 {
c0: Fq::zero(),
c1: Fq::zero(),
},
Fq2::zero()
);
assert_eq!(
Fq2 {
c0: Fq::one(),
c1: Fq::zero(),
},
Fq2::one()
);
assert!(Fq2::zero().is_zero());
assert!(!Fq2::one().is_zero());
assert!(!Fq2 {
c0: Fq::zero(),
c1: Fq::one(),
}.is_zero());
}
#[test]
fn test_fq2_squaring() {
use super::fq::FqRepr;
use PrimeField;
let mut a = Fq2 {
c0: Fq::one(),
c1: Fq::one(),
}; // u + 1
a.square();
assert_eq!(
a,
Fq2 {
c0: Fq::zero(),
c1: Fq::from_repr(FqRepr::from(2)).unwrap(),
}
); // 2u
let mut a = Fq2 {
c0: Fq::zero(),
c1: Fq::one(),
}; // u
a.square();
assert_eq!(a, {
let mut neg1 = Fq::one();
neg1.negate();
Fq2 {
c0: neg1,
c1: Fq::zero(),
}
}); // -1
let mut a = Fq2 {
c0: Fq::from_repr(FqRepr([
0x9c2c6309bbf8b598,
0x4eef5c946536f602,
0x90e34aab6fb6a6bd,
0xf7f295a94e58ae7c,
0x41b76dcc1c3fbe5e,
0x7080c5fa1d8e042,
])).unwrap(),
c1: Fq::from_repr(FqRepr([
0x38f473b3c870a4ab,
0x6ad3291177c8c7e5,
0xdac5a4c911a4353e,
0xbfb99020604137a0,
0xfc58a7b7be815407,
0x10d1615e75250a21,
])).unwrap(),
};
a.square();
assert_eq!(
a,
Fq2 {
c0: Fq::from_repr(FqRepr([
0xf262c28c538bcf68,
0xb9f2a66eae1073ba,
0xdc46ab8fad67ae0,
0xcb674157618da176,
0x4cf17b5893c3d327,
0x7eac81369c43361
])).unwrap(),
c1: Fq::from_repr(FqRepr([
0xc1579cf58e980cf8,
0xa23eb7e12dd54d98,
0xe75138bce4cec7aa,
0x38d0d7275a9689e1,
0x739c983042779a65,
0x1542a61c8a8db994
])).unwrap(),
}
);
}
#[test]
fn test_fq2_mul() {
use super::fq::FqRepr;
use PrimeField;
let mut a = Fq2 {
c0: Fq::from_repr(FqRepr([
0x85c9f989e1461f03,
0xa2e33c333449a1d6,
0x41e461154a7354a3,
0x9ee53e7e84d7532e,
0x1c202d8ed97afb45,
0x51d3f9253e2516f,
])).unwrap(),
c1: Fq::from_repr(FqRepr([
0xa7348a8b511aedcf,
0x143c215d8176b319,
0x4cc48081c09b8903,
0x9533e4a9a5158be,
0x7a5e1ecb676d65f9,
0x180c3ee46656b008,
])).unwrap(),
};
a.mul_assign(&Fq2 {
c0: Fq::from_repr(FqRepr([
0xe21f9169805f537e,
0xfc87e62e179c285d,
0x27ece175be07a531,
0xcd460f9f0c23e430,
0x6c9110292bfa409,
0x2c93a72eb8af83e,
])).unwrap(),
c1: Fq::from_repr(FqRepr([
0x4b1c3f936d8992d4,
0x1d2a72916dba4c8a,
0x8871c508658d1e5f,
0x57a06d3135a752ae,
0x634cd3c6c565096d,
0x19e17334d4e93558,
])).unwrap(),
});
assert_eq!(
a,
Fq2 {
c0: Fq::from_repr(FqRepr([
0x95b5127e6360c7e4,
0xde29c31a19a6937e,
0xf61a96dacf5a39bc,
0x5511fe4d84ee5f78,
0x5310a202d92f9963,
0x1751afbe166e5399
])).unwrap(),
c1: Fq::from_repr(FqRepr([
0x84af0e1bd630117a,
0x6c63cd4da2c2aa7,
0x5ba6e5430e883d40,
0xc975106579c275ee,
0x33a9ac82ce4c5083,
0x1ef1a36c201589d
])).unwrap(),
}
);
}
#[test]
fn test_fq2_inverse() {
use super::fq::FqRepr;
use PrimeField;
assert!(Fq2::zero().inverse().is_none());
let a = Fq2 {
c0: Fq::from_repr(FqRepr([
0x85c9f989e1461f03,
0xa2e33c333449a1d6,
0x41e461154a7354a3,
0x9ee53e7e84d7532e,
0x1c202d8ed97afb45,
0x51d3f9253e2516f,
])).unwrap(),
c1: Fq::from_repr(FqRepr([
0xa7348a8b511aedcf,
0x143c215d8176b319,
0x4cc48081c09b8903,
0x9533e4a9a5158be,
0x7a5e1ecb676d65f9,
0x180c3ee46656b008,
])).unwrap(),
};
let a = a.inverse().unwrap();
assert_eq!(
a,
Fq2 {
c0: Fq::from_repr(FqRepr([
0x70300f9bcb9e594,
0xe5ecda5fdafddbb2,
0x64bef617d2915a8f,
0xdfba703293941c30,
0xa6c3d8f9586f2636,
0x1351ef01941b70c4
])).unwrap(),
c1: Fq::from_repr(FqRepr([
0x8c39fd76a8312cb4,
0x15d7b6b95defbff0,
0x947143f89faedee9,
0xcbf651a0f367afb2,
0xdf4e54f0d3ef15a6,
0x103bdf241afb0019
])).unwrap(),
}
);
}
#[test]
fn test_fq2_addition() {
use super::fq::FqRepr;
use PrimeField;
let mut a = Fq2 {
c0: Fq::from_repr(FqRepr([
0x2d0078036923ffc7,
0x11e59ea221a3b6d2,
0x8b1a52e0a90f59ed,
0xb966ce3bc2108b13,
0xccc649c4b9532bf3,
0xf8d295b2ded9dc,
])).unwrap(),
c1: Fq::from_repr(FqRepr([
0x977df6efcdaee0db,
0x946ae52d684fa7ed,
0xbe203411c66fb3a5,
0xb3f8afc0ee248cad,
0x4e464dea5bcfd41e,
0x12d1137b8a6a837,
])).unwrap(),
};
a.add_assign(&Fq2 {
c0: Fq::from_repr(FqRepr([
0x619a02d78dc70ef2,
0xb93adfc9119e33e8,
0x4bf0b99a9f0dca12,
0x3b88899a42a6318f,
0x986a4a62fa82a49d,
0x13ce433fa26027f5,
])).unwrap(),
c1: Fq::from_repr(FqRepr([
0x66323bf80b58b9b9,
0xa1379b6facf6e596,
0x402aef1fb797e32f,
0x2236f55246d0d44d,
0x4c8c1800eb104566,
0x11d6e20e986c2085,
])).unwrap(),
});
assert_eq!(
a,
Fq2 {
c0: Fq::from_repr(FqRepr([
0x8e9a7adaf6eb0eb9,
0xcb207e6b3341eaba,
0xd70b0c7b481d23ff,
0xf4ef57d604b6bca2,
0x65309427b3d5d090,
0x14c715d5553f01d2
])).unwrap(),
c1: Fq::from_repr(FqRepr([
0xfdb032e7d9079a94,
0x35a2809d15468d83,
0xfe4b23317e0796d5,
0xd62fa51334f560fa,
0x9ad265eb46e01984,
0x1303f3465112c8bc
])).unwrap(),
}
);
}
#[test]
fn test_fq2_subtraction() {
use super::fq::FqRepr;
use PrimeField;
let mut a = Fq2 {
c0: Fq::from_repr(FqRepr([
0x2d0078036923ffc7,
0x11e59ea221a3b6d2,
0x8b1a52e0a90f59ed,
0xb966ce3bc2108b13,
0xccc649c4b9532bf3,
0xf8d295b2ded9dc,
])).unwrap(),
c1: Fq::from_repr(FqRepr([
0x977df6efcdaee0db,
0x946ae52d684fa7ed,
0xbe203411c66fb3a5,
0xb3f8afc0ee248cad,
0x4e464dea5bcfd41e,
0x12d1137b8a6a837,
])).unwrap(),
};
a.sub_assign(&Fq2 {
c0: Fq::from_repr(FqRepr([
0x619a02d78dc70ef2,
0xb93adfc9119e33e8,
0x4bf0b99a9f0dca12,
0x3b88899a42a6318f,
0x986a4a62fa82a49d,
0x13ce433fa26027f5,
])).unwrap(),
c1: Fq::from_repr(FqRepr([
0x66323bf80b58b9b9,
0xa1379b6facf6e596,
0x402aef1fb797e32f,
0x2236f55246d0d44d,
0x4c8c1800eb104566,
0x11d6e20e986c2085,
])).unwrap(),
});
assert_eq!(
a,
Fq2 {
c0: Fq::from_repr(FqRepr([
0x8565752bdb5c9b80,
0x7756bed7c15982e9,
0xa65a6be700b285fe,
0xe255902672ef6c43,
0x7f77a718021c342d,
0x72ba14049fe9881
])).unwrap(),
c1: Fq::from_repr(FqRepr([
0xeb4abaf7c255d1cd,
0x11df49bc6cacc256,
0xe52617930588c69a,
0xf63905f39ad8cb1f,
0x4cd5dd9fb40b3b8f,
0x957411359ba6e4c
])).unwrap(),
}
);
}
#[test]
fn test_fq2_negation() {
use super::fq::FqRepr;
use PrimeField;
let mut a = Fq2 {
c0: Fq::from_repr(FqRepr([
0x2d0078036923ffc7,
0x11e59ea221a3b6d2,
0x8b1a52e0a90f59ed,
0xb966ce3bc2108b13,
0xccc649c4b9532bf3,
0xf8d295b2ded9dc,
])).unwrap(),
c1: Fq::from_repr(FqRepr([
0x977df6efcdaee0db,
0x946ae52d684fa7ed,
0xbe203411c66fb3a5,
0xb3f8afc0ee248cad,
0x4e464dea5bcfd41e,
0x12d1137b8a6a837,
])).unwrap(),
};
a.negate();
assert_eq!(
a,
Fq2 {
c0: Fq::from_repr(FqRepr([
0x8cfe87fc96dbaae4,
0xcc6615c8fb0492d,
0xdc167fc04da19c37,
0xab107d49317487ab,
0x7e555df189f880e3,
0x19083f5486a10cbd
])).unwrap(),
c1: Fq::from_repr(FqRepr([
0x228109103250c9d0,
0x8a411ad149045812,
0xa9109e8f3041427e,
0xb07e9bc405608611,
0xfcd559cbe77bd8b8,
0x18d400b280d93e62
])).unwrap(),
}
);
}
#[test]
fn test_fq2_doubling() {
use super::fq::FqRepr;
use PrimeField;
let mut a = Fq2 {
c0: Fq::from_repr(FqRepr([
0x2d0078036923ffc7,
0x11e59ea221a3b6d2,
0x8b1a52e0a90f59ed,
0xb966ce3bc2108b13,
0xccc649c4b9532bf3,
0xf8d295b2ded9dc,
])).unwrap(),
c1: Fq::from_repr(FqRepr([
0x977df6efcdaee0db,
0x946ae52d684fa7ed,
0xbe203411c66fb3a5,
0xb3f8afc0ee248cad,
0x4e464dea5bcfd41e,
0x12d1137b8a6a837,
])).unwrap(),
};
a.double();
assert_eq!(
a,
Fq2 {
c0: Fq::from_repr(FqRepr([
0x5a00f006d247ff8e,
0x23cb3d4443476da4,
0x1634a5c1521eb3da,
0x72cd9c7784211627,
0x998c938972a657e7,
0x1f1a52b65bdb3b9
])).unwrap(),
c1: Fq::from_repr(FqRepr([
0x2efbeddf9b5dc1b6,
0x28d5ca5ad09f4fdb,
0x7c4068238cdf674b,
0x67f15f81dc49195b,
0x9c8c9bd4b79fa83d,
0x25a226f714d506e
])).unwrap(),
}
);
}
#[test]
fn test_fq2_frobenius_map() {
use super::fq::FqRepr;
use PrimeField;
let mut a = Fq2 {
c0: Fq::from_repr(FqRepr([
0x2d0078036923ffc7,
0x11e59ea221a3b6d2,
0x8b1a52e0a90f59ed,
0xb966ce3bc2108b13,
0xccc649c4b9532bf3,
0xf8d295b2ded9dc,
])).unwrap(),
c1: Fq::from_repr(FqRepr([
0x977df6efcdaee0db,
0x946ae52d684fa7ed,
0xbe203411c66fb3a5,
0xb3f8afc0ee248cad,
0x4e464dea5bcfd41e,
0x12d1137b8a6a837,
])).unwrap(),
};
a.frobenius_map(0);
assert_eq!(
a,
Fq2 {
c0: Fq::from_repr(FqRepr([
0x2d0078036923ffc7,
0x11e59ea221a3b6d2,
0x8b1a52e0a90f59ed,
0xb966ce3bc2108b13,
0xccc649c4b9532bf3,
0xf8d295b2ded9dc
])).unwrap(),
c1: Fq::from_repr(FqRepr([
0x977df6efcdaee0db,
0x946ae52d684fa7ed,
0xbe203411c66fb3a5,
0xb3f8afc0ee248cad,
0x4e464dea5bcfd41e,
0x12d1137b8a6a837
])).unwrap(),
}
);
a.frobenius_map(1);
assert_eq!(
a,
Fq2 {
c0: Fq::from_repr(FqRepr([
0x2d0078036923ffc7,
0x11e59ea221a3b6d2,
0x8b1a52e0a90f59ed,
0xb966ce3bc2108b13,
0xccc649c4b9532bf3,
0xf8d295b2ded9dc
])).unwrap(),
c1: Fq::from_repr(FqRepr([
0x228109103250c9d0,
0x8a411ad149045812,
0xa9109e8f3041427e,
0xb07e9bc405608611,
0xfcd559cbe77bd8b8,
0x18d400b280d93e62
])).unwrap(),
}
);
a.frobenius_map(1);
assert_eq!(
a,
Fq2 {
c0: Fq::from_repr(FqRepr([
0x2d0078036923ffc7,
0x11e59ea221a3b6d2,
0x8b1a52e0a90f59ed,
0xb966ce3bc2108b13,
0xccc649c4b9532bf3,
0xf8d295b2ded9dc
])).unwrap(),
c1: Fq::from_repr(FqRepr([
0x977df6efcdaee0db,
0x946ae52d684fa7ed,
0xbe203411c66fb3a5,
0xb3f8afc0ee248cad,
0x4e464dea5bcfd41e,
0x12d1137b8a6a837
])).unwrap(),
}
);
a.frobenius_map(2);
assert_eq!(
a,
Fq2 {
c0: Fq::from_repr(FqRepr([
0x2d0078036923ffc7,
0x11e59ea221a3b6d2,
0x8b1a52e0a90f59ed,
0xb966ce3bc2108b13,
0xccc649c4b9532bf3,
0xf8d295b2ded9dc
])).unwrap(),
c1: Fq::from_repr(FqRepr([
0x977df6efcdaee0db,
0x946ae52d684fa7ed,
0xbe203411c66fb3a5,
0xb3f8afc0ee248cad,
0x4e464dea5bcfd41e,
0x12d1137b8a6a837
])).unwrap(),
}
);
}
#[test]
fn test_fq2_sqrt() {
use super::fq::FqRepr;
use PrimeField;
assert_eq!(
Fq2 {
c0: Fq::from_repr(FqRepr([
0x476b4c309720e227,
0x34c2d04faffdab6,
0xa57e6fc1bab51fd9,
0xdb4a116b5bf74aa1,
0x1e58b2159dfe10e2,
0x7ca7da1f13606ac
])).unwrap(),
c1: Fq::from_repr(FqRepr([
0xfa8de88b7516d2c3,
0x371a75ed14f41629,
0x4cec2dca577a3eb6,
0x212611bca4e99121,
0x8ee5394d77afb3d,
0xec92336650e49d5
])).unwrap(),
}.sqrt()
.unwrap(),
Fq2 {
c0: Fq::from_repr(FqRepr([
0x40b299b2704258c5,
0x6ef7de92e8c68b63,
0x6d2ddbe552203e82,
0x8d7f1f723d02c1d3,
0x881b3e01b611c070,
0x10f6963bbad2ebc5
])).unwrap(),
c1: Fq::from_repr(FqRepr([
0xc099534fc209e752,
0x7670594665676447,
0x28a20faed211efe7,
0x6b852aeaf2afcb1b,
0xa4c93b08105d71a9,
0x8d7cfff94216330
])).unwrap(),
}
);
assert_eq!(
Fq2 {
c0: Fq::from_repr(FqRepr([
0xb9f78429d1517a6b,
0x1eabfffeb153ffff,
0x6730d2a0f6b0f624,
0x64774b84f38512bf,
0x4b1ba7b6434bacd7,
0x1a0111ea397fe69a
])).unwrap(),
c1: Fq::zero(),
}.sqrt()
.unwrap(),
Fq2 {
c0: Fq::zero(),
c1: Fq::from_repr(FqRepr([
0xb9fefffffd4357a3,
0x1eabfffeb153ffff,
0x6730d2a0f6b0f624,
0x64774b84f38512bf,
0x4b1ba7b6434bacd7,
0x1a0111ea397fe69a
])).unwrap(),
}
);
}
#[test]
fn test_fq2_legendre() {
use LegendreSymbol::*;
assert_eq!(Zero, Fq2::zero().legendre());
// i^2 = -1
let mut m1 = Fq2::one();
m1.negate();
assert_eq!(QuadraticResidue, m1.legendre());
m1.mul_by_nonresidue();
assert_eq!(QuadraticNonResidue, m1.legendre());
}
#[cfg(test)]
use rand::{SeedableRng, XorShiftRng};
#[test]
fn test_fq2_mul_nonresidue() {
let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
let nqr = Fq2 {
c0: Fq::one(),
c1: Fq::one(),
};
for _ in 0..1000 {
let mut a = Fq2::rand(&mut rng);
let mut b = a;
a.mul_by_nonresidue();
b.mul_assign(&nqr);
assert_eq!(a, b);
}
}
#[test]
fn fq2_field_tests() {
use PrimeField;
::tests::field::random_field_tests::<Fq2>();
::tests::field::random_sqrt_tests::<Fq2>();
::tests::field::random_frobenius_tests::<Fq2, _>(super::fq::Fq::char(), 13);
}

374
pairing/src/bls12_381/fq6.rs Normal file
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@@ -0,0 +1,374 @@
use super::fq::{FROBENIUS_COEFF_FQ6_C1, FROBENIUS_COEFF_FQ6_C2};
use super::fq2::Fq2;
use rand::{Rand, Rng};
use Field;
/// An element of Fq6, represented by c0 + c1 * v + c2 * v^(2).
#[derive(Copy, Clone, Debug, Eq, PartialEq)]
pub struct Fq6 {
pub c0: Fq2,
pub c1: Fq2,
pub c2: Fq2,
}
impl ::std::fmt::Display for Fq6 {
fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {
write!(f, "Fq6({} + {} * v, {} * v^2)", self.c0, self.c1, self.c2)
}
}
impl Rand for Fq6 {
fn rand<R: Rng>(rng: &mut R) -> Self {
Fq6 {
c0: rng.gen(),
c1: rng.gen(),
c2: rng.gen(),
}
}
}
impl Fq6 {
/// Multiply by quadratic nonresidue v.
pub fn mul_by_nonresidue(&mut self) {
use std::mem::swap;
swap(&mut self.c0, &mut self.c1);
swap(&mut self.c0, &mut self.c2);
self.c0.mul_by_nonresidue();
}
pub fn mul_by_1(&mut self, c1: &Fq2) {
let mut b_b = self.c1;
b_b.mul_assign(c1);
let mut t1 = *c1;
{
let mut tmp = self.c1;
tmp.add_assign(&self.c2);
t1.mul_assign(&tmp);
t1.sub_assign(&b_b);
t1.mul_by_nonresidue();
}
let mut t2 = *c1;
{
let mut tmp = self.c0;
tmp.add_assign(&self.c1);
t2.mul_assign(&tmp);
t2.sub_assign(&b_b);
}
self.c0 = t1;
self.c1 = t2;
self.c2 = b_b;
}
pub fn mul_by_01(&mut self, c0: &Fq2, c1: &Fq2) {
let mut a_a = self.c0;
let mut b_b = self.c1;
a_a.mul_assign(c0);
b_b.mul_assign(c1);
let mut t1 = *c1;
{
let mut tmp = self.c1;
tmp.add_assign(&self.c2);
t1.mul_assign(&tmp);
t1.sub_assign(&b_b);
t1.mul_by_nonresidue();
t1.add_assign(&a_a);
}
let mut t3 = *c0;
{
let mut tmp = self.c0;
tmp.add_assign(&self.c2);
t3.mul_assign(&tmp);
t3.sub_assign(&a_a);
t3.add_assign(&b_b);
}
let mut t2 = *c0;
t2.add_assign(c1);
{
let mut tmp = self.c0;
tmp.add_assign(&self.c1);
t2.mul_assign(&tmp);
t2.sub_assign(&a_a);
t2.sub_assign(&b_b);
}
self.c0 = t1;
self.c1 = t2;
self.c2 = t3;
}
}
impl Field for Fq6 {
fn zero() -> Self {
Fq6 {
c0: Fq2::zero(),
c1: Fq2::zero(),
c2: Fq2::zero(),
}
}
fn one() -> Self {
Fq6 {
c0: Fq2::one(),
c1: Fq2::zero(),
c2: Fq2::zero(),
}
}
fn is_zero(&self) -> bool {
self.c0.is_zero() && self.c1.is_zero() && self.c2.is_zero()
}
fn double(&mut self) {
self.c0.double();
self.c1.double();
self.c2.double();
}
fn negate(&mut self) {
self.c0.negate();
self.c1.negate();
self.c2.negate();
}
fn add_assign(&mut self, other: &Self) {
self.c0.add_assign(&other.c0);
self.c1.add_assign(&other.c1);
self.c2.add_assign(&other.c2);
}
fn sub_assign(&mut self, other: &Self) {
self.c0.sub_assign(&other.c0);
self.c1.sub_assign(&other.c1);
self.c2.sub_assign(&other.c2);
}
fn frobenius_map(&mut self, power: usize) {
self.c0.frobenius_map(power);
self.c1.frobenius_map(power);
self.c2.frobenius_map(power);
self.c1.mul_assign(&FROBENIUS_COEFF_FQ6_C1[power % 6]);
self.c2.mul_assign(&FROBENIUS_COEFF_FQ6_C2[power % 6]);
}
fn square(&mut self) {
let mut s0 = self.c0;
s0.square();
let mut ab = self.c0;
ab.mul_assign(&self.c1);
let mut s1 = ab;
s1.double();
let mut s2 = self.c0;
s2.sub_assign(&self.c1);
s2.add_assign(&self.c2);
s2.square();
let mut bc = self.c1;
bc.mul_assign(&self.c2);
let mut s3 = bc;
s3.double();
let mut s4 = self.c2;
s4.square();
self.c0 = s3;
self.c0.mul_by_nonresidue();
self.c0.add_assign(&s0);
self.c1 = s4;
self.c1.mul_by_nonresidue();
self.c1.add_assign(&s1);
self.c2 = s1;
self.c2.add_assign(&s2);
self.c2.add_assign(&s3);
self.c2.sub_assign(&s0);
self.c2.sub_assign(&s4);
}
fn mul_assign(&mut self, other: &Self) {
let mut a_a = self.c0;
let mut b_b = self.c1;
let mut c_c = self.c2;
a_a.mul_assign(&other.c0);
b_b.mul_assign(&other.c1);
c_c.mul_assign(&other.c2);
let mut t1 = other.c1;
t1.add_assign(&other.c2);
{
let mut tmp = self.c1;
tmp.add_assign(&self.c2);
t1.mul_assign(&tmp);
t1.sub_assign(&b_b);
t1.sub_assign(&c_c);
t1.mul_by_nonresidue();
t1.add_assign(&a_a);
}
let mut t3 = other.c0;
t3.add_assign(&other.c2);
{
let mut tmp = self.c0;
tmp.add_assign(&self.c2);
t3.mul_assign(&tmp);
t3.sub_assign(&a_a);
t3.add_assign(&b_b);
t3.sub_assign(&c_c);
}
let mut t2 = other.c0;
t2.add_assign(&other.c1);
{
let mut tmp = self.c0;
tmp.add_assign(&self.c1);
t2.mul_assign(&tmp);
t2.sub_assign(&a_a);
t2.sub_assign(&b_b);
c_c.mul_by_nonresidue();
t2.add_assign(&c_c);
}
self.c0 = t1;
self.c1 = t2;
self.c2 = t3;
}
fn inverse(&self) -> Option<Self> {
let mut c0 = self.c2;
c0.mul_by_nonresidue();
c0.mul_assign(&self.c1);
c0.negate();
{
let mut c0s = self.c0;
c0s.square();
c0.add_assign(&c0s);
}
let mut c1 = self.c2;
c1.square();
c1.mul_by_nonresidue();
{
let mut c01 = self.c0;
c01.mul_assign(&self.c1);
c1.sub_assign(&c01);
}
let mut c2 = self.c1;
c2.square();
{
let mut c02 = self.c0;
c02.mul_assign(&self.c2);
c2.sub_assign(&c02);
}
let mut tmp1 = self.c2;
tmp1.mul_assign(&c1);
let mut tmp2 = self.c1;
tmp2.mul_assign(&c2);
tmp1.add_assign(&tmp2);
tmp1.mul_by_nonresidue();
tmp2 = self.c0;
tmp2.mul_assign(&c0);
tmp1.add_assign(&tmp2);
match tmp1.inverse() {
Some(t) => {
let mut tmp = Fq6 {
c0: t,
c1: t,
c2: t,
};
tmp.c0.mul_assign(&c0);
tmp.c1.mul_assign(&c1);
tmp.c2.mul_assign(&c2);
Some(tmp)
}
None => None,
}
}
}
#[cfg(test)]
use rand::{SeedableRng, XorShiftRng};
#[test]
fn test_fq6_mul_nonresidue() {
let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
let nqr = Fq6 {
c0: Fq2::zero(),
c1: Fq2::one(),
c2: Fq2::zero(),
};
for _ in 0..1000 {
let mut a = Fq6::rand(&mut rng);
let mut b = a;
a.mul_by_nonresidue();
b.mul_assign(&nqr);
assert_eq!(a, b);
}
}
#[test]
fn test_fq6_mul_by_1() {
let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
for _ in 0..1000 {
let c1 = Fq2::rand(&mut rng);
let mut a = Fq6::rand(&mut rng);
let mut b = a;
a.mul_by_1(&c1);
b.mul_assign(&Fq6 {
c0: Fq2::zero(),
c1: c1,
c2: Fq2::zero(),
});
assert_eq!(a, b);
}
}
#[test]
fn test_fq6_mul_by_01() {
let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
for _ in 0..1000 {
let c0 = Fq2::rand(&mut rng);
let c1 = Fq2::rand(&mut rng);
let mut a = Fq6::rand(&mut rng);
let mut b = a;
a.mul_by_01(&c0, &c1);
b.mul_assign(&Fq6 {
c0: c0,
c1: c1,
c2: Fq2::zero(),
});
assert_eq!(a, b);
}
}
#[test]
fn fq6_field_tests() {
use PrimeField;
::tests::field::random_field_tests::<Fq6>();
::tests::field::random_frobenius_tests::<Fq6, _>(super::fq::Fq::char(), 13);
}

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mod ec;
mod fq;
mod fq12;
mod fq2;
mod fq6;
mod fr;
#[cfg(test)]
mod tests;
pub use self::ec::{
G1, G1Affine, G1Compressed, G1Prepared, G1Uncompressed, G2, G2Affine, G2Compressed, G2Prepared,
G2Uncompressed,
};
pub use self::fq::{Fq, FqRepr};
pub use self::fq12::Fq12;
pub use self::fq2::Fq2;
pub use self::fq6::Fq6;
pub use self::fr::{Fr, FrRepr};
use super::{BitIterator, CurveAffine, Engine, Field};
// The BLS parameter x for BLS12-381 is -0xd201000000010000
const BLS_X: u64 = 0xd201000000010000;
const BLS_X_IS_NEGATIVE: bool = true;
#[derive(Clone, Debug)]
pub struct Bls12;
impl Engine for Bls12 {
type Fr = Fr;
type G1 = G1;
type G1Affine = G1Affine;
type G2 = G2;
type G2Affine = G2Affine;
type Fq = Fq;
type Fqe = Fq2;
type Fqk = Fq12;
fn miller_loop<'a, I>(i: I) -> Self::Fqk
where
I: IntoIterator<
Item = &'a (
&'a <Self::G1Affine as CurveAffine>::Prepared,
&'a <Self::G2Affine as CurveAffine>::Prepared,
),
>,
{
let mut pairs = vec![];
for &(p, q) in i {
if !p.is_zero() && !q.is_zero() {
pairs.push((p, q.coeffs.iter()));
}
}
// Twisting isomorphism from E to E'
fn ell(f: &mut Fq12, coeffs: &(Fq2, Fq2, Fq2), p: &G1Affine) {
let mut c0 = coeffs.0;
let mut c1 = coeffs.1;
c0.c0.mul_assign(&p.y);
c0.c1.mul_assign(&p.y);
c1.c0.mul_assign(&p.x);
c1.c1.mul_assign(&p.x);
// Sparse multiplication in Fq12
f.mul_by_014(&coeffs.2, &c1, &c0);
}
let mut f = Fq12::one();
let mut found_one = false;
for i in BitIterator::new(&[BLS_X >> 1]) {
if !found_one {
found_one = i;
continue;
}
for &mut (p, ref mut coeffs) in &mut pairs {
ell(&mut f, coeffs.next().unwrap(), &p.0);
}
if i {
for &mut (p, ref mut coeffs) in &mut pairs {
ell(&mut f, coeffs.next().unwrap(), &p.0);
}
}
f.square();
}
for &mut (p, ref mut coeffs) in &mut pairs {
ell(&mut f, coeffs.next().unwrap(), &p.0);
}
if BLS_X_IS_NEGATIVE {
f.conjugate();
}
f
}
fn final_exponentiation(r: &Fq12) -> Option<Fq12> {
let mut f1 = *r;
f1.conjugate();
match r.inverse() {
Some(mut f2) => {
let mut r = f1;
r.mul_assign(&f2);
f2 = r;
r.frobenius_map(2);
r.mul_assign(&f2);
fn exp_by_x(f: &mut Fq12, x: u64) {
*f = f.pow(&[x]);
if BLS_X_IS_NEGATIVE {
f.conjugate();
}
}
let mut x = BLS_X;
let mut y0 = r;
y0.square();
let mut y1 = y0;
exp_by_x(&mut y1, x);
x >>= 1;
let mut y2 = y1;
exp_by_x(&mut y2, x);
x <<= 1;
let mut y3 = r;
y3.conjugate();
y1.mul_assign(&y3);
y1.conjugate();
y1.mul_assign(&y2);
y2 = y1;
exp_by_x(&mut y2, x);
y3 = y2;
exp_by_x(&mut y3, x);
y1.conjugate();
y3.mul_assign(&y1);
y1.conjugate();
y1.frobenius_map(3);
y2.frobenius_map(2);
y1.mul_assign(&y2);
y2 = y3;
exp_by_x(&mut y2, x);
y2.mul_assign(&y0);
y2.mul_assign(&r);
y1.mul_assign(&y2);
y2 = y3;
y2.frobenius_map(1);
y1.mul_assign(&y2);
Some(y1)
}
None => None,
}
}
}
impl G2Prepared {
pub fn is_zero(&self) -> bool {
self.infinity
}
pub fn from_affine(q: G2Affine) -> Self {
if q.is_zero() {
return G2Prepared {
coeffs: vec![],
infinity: true,
};
}
fn doubling_step(r: &mut G2) -> (Fq2, Fq2, Fq2) {
// Adaptation of Algorithm 26, https://eprint.iacr.org/2010/354.pdf
let mut tmp0 = r.x;
tmp0.square();
let mut tmp1 = r.y;
tmp1.square();
let mut tmp2 = tmp1;
tmp2.square();
let mut tmp3 = tmp1;
tmp3.add_assign(&r.x);
tmp3.square();
tmp3.sub_assign(&tmp0);
tmp3.sub_assign(&tmp2);
tmp3.double();
let mut tmp4 = tmp0;
tmp4.double();
tmp4.add_assign(&tmp0);
let mut tmp6 = r.x;
tmp6.add_assign(&tmp4);
let mut tmp5 = tmp4;
tmp5.square();
let mut zsquared = r.z;
zsquared.square();
r.x = tmp5;
r.x.sub_assign(&tmp3);
r.x.sub_assign(&tmp3);
r.z.add_assign(&r.y);
r.z.square();
r.z.sub_assign(&tmp1);
r.z.sub_assign(&zsquared);
r.y = tmp3;
r.y.sub_assign(&r.x);
r.y.mul_assign(&tmp4);
tmp2.double();
tmp2.double();
tmp2.double();
r.y.sub_assign(&tmp2);
tmp3 = tmp4;
tmp3.mul_assign(&zsquared);
tmp3.double();
tmp3.negate();
tmp6.square();
tmp6.sub_assign(&tmp0);
tmp6.sub_assign(&tmp5);
tmp1.double();
tmp1.double();
tmp6.sub_assign(&tmp1);
tmp0 = r.z;
tmp0.mul_assign(&zsquared);
tmp0.double();
(tmp0, tmp3, tmp6)
}
fn addition_step(r: &mut G2, q: &G2Affine) -> (Fq2, Fq2, Fq2) {
// Adaptation of Algorithm 27, https://eprint.iacr.org/2010/354.pdf
let mut zsquared = r.z;
zsquared.square();
let mut ysquared = q.y;
ysquared.square();
let mut t0 = zsquared;
t0.mul_assign(&q.x);
let mut t1 = q.y;
t1.add_assign(&r.z);
t1.square();
t1.sub_assign(&ysquared);
t1.sub_assign(&zsquared);
t1.mul_assign(&zsquared);
let mut t2 = t0;
t2.sub_assign(&r.x);
let mut t3 = t2;
t3.square();
let mut t4 = t3;
t4.double();
t4.double();
let mut t5 = t4;
t5.mul_assign(&t2);
let mut t6 = t1;
t6.sub_assign(&r.y);
t6.sub_assign(&r.y);
let mut t9 = t6;
t9.mul_assign(&q.x);
let mut t7 = t4;
t7.mul_assign(&r.x);
r.x = t6;
r.x.square();
r.x.sub_assign(&t5);
r.x.sub_assign(&t7);
r.x.sub_assign(&t7);
r.z.add_assign(&t2);
r.z.square();
r.z.sub_assign(&zsquared);
r.z.sub_assign(&t3);
let mut t10 = q.y;
t10.add_assign(&r.z);
let mut t8 = t7;
t8.sub_assign(&r.x);
t8.mul_assign(&t6);
t0 = r.y;
t0.mul_assign(&t5);
t0.double();
r.y = t8;
r.y.sub_assign(&t0);
t10.square();
t10.sub_assign(&ysquared);
let mut ztsquared = r.z;
ztsquared.square();
t10.sub_assign(&ztsquared);
t9.double();
t9.sub_assign(&t10);
t10 = r.z;
t10.double();
t6.negate();
t1 = t6;
t1.double();
(t10, t1, t9)
}
let mut coeffs = vec![];
let mut r: G2 = q.into();
let mut found_one = false;
for i in BitIterator::new([BLS_X >> 1]) {
if !found_one {
found_one = i;
continue;
}
coeffs.push(doubling_step(&mut r));
if i {
coeffs.push(addition_step(&mut r, &q));
}
}
coeffs.push(doubling_step(&mut r));
G2Prepared {
coeffs,
infinity: false,
}
}
}
#[test]
fn bls12_engine_tests() {
::tests::engine::engine_tests::<Bls12>();
}

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pairing/src/bls12_381/tests/mod.rs Normal file
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use super::*;
use *;
#[test]
fn test_pairing_result_against_relic() {
/*
Sent to me from Diego Aranha (author of RELIC library):
1250EBD871FC0A92 A7B2D83168D0D727 272D441BEFA15C50 3DD8E90CE98DB3E7 B6D194F60839C508 A84305AACA1789B6
089A1C5B46E5110B 86750EC6A5323488 68A84045483C92B7 AF5AF689452EAFAB F1A8943E50439F1D 59882A98EAA0170F
1368BB445C7C2D20 9703F239689CE34C 0378A68E72A6B3B2 16DA0E22A5031B54 DDFF57309396B38C 881C4C849EC23E87
193502B86EDB8857 C273FA075A505129 37E0794E1E65A761 7C90D8BD66065B1F FFE51D7A579973B1 315021EC3C19934F
01B2F522473D1713 91125BA84DC4007C FBF2F8DA752F7C74 185203FCCA589AC7 19C34DFFBBAAD843 1DAD1C1FB597AAA5
018107154F25A764 BD3C79937A45B845 46DA634B8F6BE14A 8061E55CCEBA478B 23F7DACAA35C8CA7 8BEAE9624045B4B6
19F26337D205FB46 9CD6BD15C3D5A04D C88784FBB3D0B2DB DEA54D43B2B73F2C BB12D58386A8703E 0F948226E47EE89D
06FBA23EB7C5AF0D 9F80940CA771B6FF D5857BAAF222EB95 A7D2809D61BFE02E 1BFD1B68FF02F0B8 102AE1C2D5D5AB1A
11B8B424CD48BF38 FCEF68083B0B0EC5 C81A93B330EE1A67 7D0D15FF7B984E89 78EF48881E32FAC9 1B93B47333E2BA57
03350F55A7AEFCD3 C31B4FCB6CE5771C C6A0E9786AB59733 20C806AD36082910 7BA810C5A09FFDD9 BE2291A0C25A99A2
04C581234D086A99 02249B64728FFD21 A189E87935A95405 1C7CDBA7B3872629 A4FAFC05066245CB 9108F0242D0FE3EF
0F41E58663BF08CF 068672CBD01A7EC7 3BACA4D72CA93544 DEFF686BFD6DF543 D48EAA24AFE47E1E FDE449383B676631
*/
assert_eq!(Bls12::pairing(G1::one(), G2::one()), Fq12 {
c0: Fq6 {
c0: Fq2 {
c0: Fq::from_str("2819105605953691245277803056322684086884703000473961065716485506033588504203831029066448642358042597501014294104502").unwrap(),
c1: Fq::from_str("1323968232986996742571315206151405965104242542339680722164220900812303524334628370163366153839984196298685227734799").unwrap()
},
c1: Fq2 {
c0: Fq::from_str("2987335049721312504428602988447616328830341722376962214011674875969052835043875658579425548512925634040144704192135").unwrap(),
c1: Fq::from_str("3879723582452552452538684314479081967502111497413076598816163759028842927668327542875108457755966417881797966271311").unwrap()
},
c2: Fq2 {
c0: Fq::from_str("261508182517997003171385743374653339186059518494239543139839025878870012614975302676296704930880982238308326681253").unwrap(),
c1: Fq::from_str("231488992246460459663813598342448669854473942105054381511346786719005883340876032043606739070883099647773793170614").unwrap()
}
},
c1: Fq6 {
c0: Fq2 {
c0: Fq::from_str("3993582095516422658773669068931361134188738159766715576187490305611759126554796569868053818105850661142222948198557").unwrap(),
c1: Fq::from_str("1074773511698422344502264006159859710502164045911412750831641680783012525555872467108249271286757399121183508900634").unwrap()
},
c1: Fq2 {
c0: Fq::from_str("2727588299083545686739024317998512740561167011046940249988557419323068809019137624943703910267790601287073339193943").unwrap(),
c1: Fq::from_str("493643299814437640914745677854369670041080344349607504656543355799077485536288866009245028091988146107059514546594").unwrap()
},
c2: Fq2 {
c0: Fq::from_str("734401332196641441839439105942623141234148957972407782257355060229193854324927417865401895596108124443575283868655").unwrap(),
c1: Fq::from_str("2348330098288556420918672502923664952620152483128593484301759394583320358354186482723629999370241674973832318248497").unwrap()
}
}
});
}
fn test_vectors<G: CurveProjective, E: EncodedPoint<Affine = G::Affine>>(expected: &[u8]) {
let mut e = G::zero();
let mut v = vec![];
{
let mut expected = expected;
for _ in 0..1000 {
let e_affine = e.into_affine();
let encoded = E::from_affine(e_affine);
v.extend_from_slice(encoded.as_ref());
let mut decoded = E::empty();
decoded.as_mut().copy_from_slice(&expected[0..E::size()]);
expected = &expected[E::size()..];
let decoded = decoded.into_affine().unwrap();
assert_eq!(e_affine, decoded);
e.add_assign(&G::one());
}
}
assert_eq!(&v[..], expected);
}
#[test]
fn test_g1_uncompressed_valid_vectors() {
test_vectors::<G1, G1Uncompressed>(include_bytes!("g1_uncompressed_valid_test_vectors.dat"));
}
#[test]
fn test_g1_compressed_valid_vectors() {
test_vectors::<G1, G1Compressed>(include_bytes!("g1_compressed_valid_test_vectors.dat"));
}
#[test]
fn test_g2_uncompressed_valid_vectors() {
test_vectors::<G2, G2Uncompressed>(include_bytes!("g2_uncompressed_valid_test_vectors.dat"));
}
#[test]
fn test_g2_compressed_valid_vectors() {
test_vectors::<G2, G2Compressed>(include_bytes!("g2_compressed_valid_test_vectors.dat"));
}
#[test]
fn test_g1_uncompressed_invalid_vectors() {
{
let z = G1Affine::zero().into_uncompressed();
{
let mut z = z;
z.as_mut()[0] |= 0b1000_0000;
if let Err(GroupDecodingError::UnexpectedCompressionMode) = z.into_affine() {
// :)
} else {
panic!("should have rejected the point because we expected an uncompressed point");
}
}
{
let mut z = z;
z.as_mut()[0] |= 0b0010_0000;
if let Err(GroupDecodingError::UnexpectedInformation) = z.into_affine() {
// :)
} else {
panic!("should have rejected the point because the parity bit should not be set if the point is at infinity");
}
}
for i in 0..G1Uncompressed::size() {
let mut z = z;
z.as_mut()[i] |= 0b0000_0001;
if let Err(GroupDecodingError::UnexpectedInformation) = z.into_affine() {
// :)
} else {
panic!("should have rejected the point because the coordinates should be zeroes at the point at infinity");
}
}
}
let o = G1Affine::one().into_uncompressed();
{
let mut o = o;
o.as_mut()[0] |= 0b1000_0000;
if let Err(GroupDecodingError::UnexpectedCompressionMode) = o.into_affine() {
// :)
} else {
panic!("should have rejected the point because we expected an uncompressed point");
}
}
let m = Fq::char();
{
let mut o = o;
m.write_be(&mut o.as_mut()[0..]).unwrap();
if let Err(GroupDecodingError::CoordinateDecodingError(coordinate, _)) = o.into_affine() {
assert_eq!(coordinate, "x coordinate");
} else {
panic!("should have rejected the point")
}
}
{
let mut o = o;
m.write_be(&mut o.as_mut()[48..]).unwrap();
if let Err(GroupDecodingError::CoordinateDecodingError(coordinate, _)) = o.into_affine() {
assert_eq!(coordinate, "y coordinate");
} else {
panic!("should have rejected the point")
}
}
{
let m = Fq::zero().into_repr();
let mut o = o;
m.write_be(&mut o.as_mut()[0..]).unwrap();
if let Err(GroupDecodingError::NotOnCurve) = o.into_affine() {
// :)
} else {
panic!("should have rejected the point because it isn't on the curve")
}
}
{
let mut o = o;
let mut x = Fq::one();
loop {
let mut x3b = x;
x3b.square();
x3b.mul_assign(&x);
x3b.add_assign(&Fq::from_repr(FqRepr::from(4)).unwrap()); // TODO: perhaps expose coeff_b through API?
if let Some(y) = x3b.sqrt() {
// We know this is on the curve, but it's likely not going to be in the correct subgroup.
x.into_repr().write_be(&mut o.as_mut()[0..]).unwrap();
y.into_repr().write_be(&mut o.as_mut()[48..]).unwrap();
if let Err(GroupDecodingError::NotInSubgroup) = o.into_affine() {
break;
} else {
panic!(
"should have rejected the point because it isn't in the correct subgroup"
)
}
} else {
x.add_assign(&Fq::one());
}
}
}
}
#[test]
fn test_g2_uncompressed_invalid_vectors() {
{
let z = G2Affine::zero().into_uncompressed();
{
let mut z = z;
z.as_mut()[0] |= 0b1000_0000;
if let Err(GroupDecodingError::UnexpectedCompressionMode) = z.into_affine() {
// :)
} else {
panic!("should have rejected the point because we expected an uncompressed point");
}
}
{
let mut z = z;
z.as_mut()[0] |= 0b0010_0000;
if let Err(GroupDecodingError::UnexpectedInformation) = z.into_affine() {
// :)
} else {
panic!("should have rejected the point because the parity bit should not be set if the point is at infinity");
}
}
for i in 0..G2Uncompressed::size() {
let mut z = z;
z.as_mut()[i] |= 0b0000_0001;
if let Err(GroupDecodingError::UnexpectedInformation) = z.into_affine() {
// :)
} else {
panic!("should have rejected the point because the coordinates should be zeroes at the point at infinity");
}
}
}
let o = G2Affine::one().into_uncompressed();
{
let mut o = o;
o.as_mut()[0] |= 0b1000_0000;
if let Err(GroupDecodingError::UnexpectedCompressionMode) = o.into_affine() {
// :)
} else {
panic!("should have rejected the point because we expected an uncompressed point");
}
}
let m = Fq::char();
{
let mut o = o;
m.write_be(&mut o.as_mut()[0..]).unwrap();
if let Err(GroupDecodingError::CoordinateDecodingError(coordinate, _)) = o.into_affine() {
assert_eq!(coordinate, "x coordinate (c1)");
} else {
panic!("should have rejected the point")
}
}
{
let mut o = o;
m.write_be(&mut o.as_mut()[48..]).unwrap();
if let Err(GroupDecodingError::CoordinateDecodingError(coordinate, _)) = o.into_affine() {
assert_eq!(coordinate, "x coordinate (c0)");
} else {
panic!("should have rejected the point")
}
}
{
let mut o = o;
m.write_be(&mut o.as_mut()[96..]).unwrap();
if let Err(GroupDecodingError::CoordinateDecodingError(coordinate, _)) = o.into_affine() {
assert_eq!(coordinate, "y coordinate (c1)");
} else {
panic!("should have rejected the point")
}
}
{
let mut o = o;
m.write_be(&mut o.as_mut()[144..]).unwrap();
if let Err(GroupDecodingError::CoordinateDecodingError(coordinate, _)) = o.into_affine() {
assert_eq!(coordinate, "y coordinate (c0)");
} else {
panic!("should have rejected the point")
}
}
{
let m = Fq::zero().into_repr();
let mut o = o;
m.write_be(&mut o.as_mut()[0..]).unwrap();
m.write_be(&mut o.as_mut()[48..]).unwrap();
if let Err(GroupDecodingError::NotOnCurve) = o.into_affine() {
// :)
} else {
panic!("should have rejected the point because it isn't on the curve")
}
}
{
let mut o = o;
let mut x = Fq2::one();
loop {
let mut x3b = x;
x3b.square();
x3b.mul_assign(&x);
x3b.add_assign(&Fq2 {
c0: Fq::from_repr(FqRepr::from(4)).unwrap(),
c1: Fq::from_repr(FqRepr::from(4)).unwrap(),
}); // TODO: perhaps expose coeff_b through API?
if let Some(y) = x3b.sqrt() {
// We know this is on the curve, but it's likely not going to be in the correct subgroup.
x.c1.into_repr().write_be(&mut o.as_mut()[0..]).unwrap();
x.c0.into_repr().write_be(&mut o.as_mut()[48..]).unwrap();
y.c1.into_repr().write_be(&mut o.as_mut()[96..]).unwrap();
y.c0.into_repr().write_be(&mut o.as_mut()[144..]).unwrap();
if let Err(GroupDecodingError::NotInSubgroup) = o.into_affine() {
break;
} else {
panic!(
"should have rejected the point because it isn't in the correct subgroup"
)
}
} else {
x.add_assign(&Fq2::one());
}
}
}
}
#[test]
fn test_g1_compressed_invalid_vectors() {
{
let z = G1Affine::zero().into_compressed();
{
let mut z = z;
z.as_mut()[0] &= 0b0111_1111;
if let Err(GroupDecodingError::UnexpectedCompressionMode) = z.into_affine() {
// :)
} else {
panic!("should have rejected the point because we expected a compressed point");
}
}
{
let mut z = z;
z.as_mut()[0] |= 0b0010_0000;
if let Err(GroupDecodingError::UnexpectedInformation) = z.into_affine() {
// :)
} else {
panic!("should have rejected the point because the parity bit should not be set if the point is at infinity");
}
}
for i in 0..G1Compressed::size() {
let mut z = z;
z.as_mut()[i] |= 0b0000_0001;
if let Err(GroupDecodingError::UnexpectedInformation) = z.into_affine() {
// :)
} else {
panic!("should have rejected the point because the coordinates should be zeroes at the point at infinity");
}
}
}
let o = G1Affine::one().into_compressed();
{
let mut o = o;
o.as_mut()[0] &= 0b0111_1111;
if let Err(GroupDecodingError::UnexpectedCompressionMode) = o.into_affine() {
// :)
} else {
panic!("should have rejected the point because we expected a compressed point");
}
}
let m = Fq::char();
{
let mut o = o;
m.write_be(&mut o.as_mut()[0..]).unwrap();
o.as_mut()[0] |= 0b1000_0000;
if let Err(GroupDecodingError::CoordinateDecodingError(coordinate, _)) = o.into_affine() {
assert_eq!(coordinate, "x coordinate");
} else {
panic!("should have rejected the point")
}
}
{
let mut o = o;
let mut x = Fq::one();
loop {
let mut x3b = x;
x3b.square();
x3b.mul_assign(&x);
x3b.add_assign(&Fq::from_repr(FqRepr::from(4)).unwrap()); // TODO: perhaps expose coeff_b through API?
if let Some(_) = x3b.sqrt() {
x.add_assign(&Fq::one());
} else {
x.into_repr().write_be(&mut o.as_mut()[0..]).unwrap();
o.as_mut()[0] |= 0b1000_0000;
if let Err(GroupDecodingError::NotOnCurve) = o.into_affine() {
break;
} else {
panic!("should have rejected the point because it isn't on the curve")
}
}
}
}
{
let mut o = o;
let mut x = Fq::one();
loop {
let mut x3b = x;
x3b.square();
x3b.mul_assign(&x);
x3b.add_assign(&Fq::from_repr(FqRepr::from(4)).unwrap()); // TODO: perhaps expose coeff_b through API?
if let Some(_) = x3b.sqrt() {
// We know this is on the curve, but it's likely not going to be in the correct subgroup.
x.into_repr().write_be(&mut o.as_mut()[0..]).unwrap();
o.as_mut()[0] |= 0b1000_0000;
if let Err(GroupDecodingError::NotInSubgroup) = o.into_affine() {
break;
} else {
panic!(
"should have rejected the point because it isn't in the correct subgroup"
)
}
} else {
x.add_assign(&Fq::one());
}
}
}
}
#[test]
fn test_g2_compressed_invalid_vectors() {
{
let z = G2Affine::zero().into_compressed();
{
let mut z = z;
z.as_mut()[0] &= 0b0111_1111;
if let Err(GroupDecodingError::UnexpectedCompressionMode) = z.into_affine() {
// :)
} else {
panic!("should have rejected the point because we expected a compressed point");
}
}
{
let mut z = z;
z.as_mut()[0] |= 0b0010_0000;
if let Err(GroupDecodingError::UnexpectedInformation) = z.into_affine() {
// :)
} else {
panic!("should have rejected the point because the parity bit should not be set if the point is at infinity");
}
}
for i in 0..G2Compressed::size() {
let mut z = z;
z.as_mut()[i] |= 0b0000_0001;
if let Err(GroupDecodingError::UnexpectedInformation) = z.into_affine() {
// :)
} else {
panic!("should have rejected the point because the coordinates should be zeroes at the point at infinity");
}
}
}
let o = G2Affine::one().into_compressed();
{
let mut o = o;
o.as_mut()[0] &= 0b0111_1111;
if let Err(GroupDecodingError::UnexpectedCompressionMode) = o.into_affine() {
// :)
} else {
panic!("should have rejected the point because we expected a compressed point");
}
}
let m = Fq::char();
{
let mut o = o;
m.write_be(&mut o.as_mut()[0..]).unwrap();
o.as_mut()[0] |= 0b1000_0000;
if let Err(GroupDecodingError::CoordinateDecodingError(coordinate, _)) = o.into_affine() {
assert_eq!(coordinate, "x coordinate (c1)");
} else {
panic!("should have rejected the point")
}
}
{
let mut o = o;
m.write_be(&mut o.as_mut()[48..]).unwrap();
o.as_mut()[0] |= 0b1000_0000;
if let Err(GroupDecodingError::CoordinateDecodingError(coordinate, _)) = o.into_affine() {
assert_eq!(coordinate, "x coordinate (c0)");
} else {
panic!("should have rejected the point")
}
}
{
let mut o = o;
let mut x = Fq2 {
c0: Fq::one(),
c1: Fq::one(),
};
loop {
let mut x3b = x;
x3b.square();
x3b.mul_assign(&x);
x3b.add_assign(&Fq2 {
c0: Fq::from_repr(FqRepr::from(4)).unwrap(),
c1: Fq::from_repr(FqRepr::from(4)).unwrap(),
}); // TODO: perhaps expose coeff_b through API?
if let Some(_) = x3b.sqrt() {
x.add_assign(&Fq2::one());
} else {
x.c1.into_repr().write_be(&mut o.as_mut()[0..]).unwrap();
x.c0.into_repr().write_be(&mut o.as_mut()[48..]).unwrap();
o.as_mut()[0] |= 0b1000_0000;
if let Err(GroupDecodingError::NotOnCurve) = o.into_affine() {
break;
} else {
panic!("should have rejected the point because it isn't on the curve")
}
}
}
}
{
let mut o = o;
let mut x = Fq2 {
c0: Fq::one(),
c1: Fq::one(),
};
loop {
let mut x3b = x;
x3b.square();
x3b.mul_assign(&x);
x3b.add_assign(&Fq2 {
c0: Fq::from_repr(FqRepr::from(4)).unwrap(),
c1: Fq::from_repr(FqRepr::from(4)).unwrap(),
}); // TODO: perhaps expose coeff_b through API?
if let Some(_) = x3b.sqrt() {
// We know this is on the curve, but it's likely not going to be in the correct subgroup.
x.c1.into_repr().write_be(&mut o.as_mut()[0..]).unwrap();
x.c0.into_repr().write_be(&mut o.as_mut()[48..]).unwrap();
o.as_mut()[0] |= 0b1000_0000;
if let Err(GroupDecodingError::NotInSubgroup) = o.into_affine() {
break;
} else {
panic!(
"should have rejected the point because it isn't in the correct subgroup"
)
}
} else {
x.add_assign(&Fq2::one());
}
}
}
}

758
pairing/src/lib.rs Normal file
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@@ -0,0 +1,758 @@
// `clippy` is a code linting tool for improving code quality by catching
// common mistakes or strange code patterns. If the `clippy` feature is
// provided, it is enabled and all compiler warnings are prohibited.
#![cfg_attr(feature = "clippy", deny(warnings))]
#![cfg_attr(feature = "clippy", feature(plugin))]
#![cfg_attr(feature = "clippy", plugin(clippy))]
#![cfg_attr(feature = "clippy", allow(inline_always))]
#![cfg_attr(feature = "clippy", allow(too_many_arguments))]
#![cfg_attr(feature = "clippy", allow(unreadable_literal))]
#![cfg_attr(feature = "clippy", allow(many_single_char_names))]
#![cfg_attr(feature = "clippy", allow(new_without_default_derive))]
#![cfg_attr(feature = "clippy", allow(write_literal))]
// Force public structures to implement Debug
#![deny(missing_debug_implementations)]
extern crate byteorder;
extern crate rand;
#[cfg(test)]
pub mod tests;
pub mod bls12_381;
mod wnaf;
pub use self::wnaf::Wnaf;
use std::error::Error;
use std::fmt;
use std::io::{self, Read, Write};
/// An "engine" is a collection of types (fields, elliptic curve groups, etc.)
/// with well-defined relationships. In particular, the G1/G2 curve groups are
/// of prime order `r`, and are equipped with a bilinear pairing function.
pub trait Engine: Sized + 'static + Clone {
/// This is the scalar field of the G1/G2 groups.
type Fr: PrimeField + SqrtField;
/// The projective representation of an element in G1.
type G1: CurveProjective<
Engine = Self,
Base = Self::Fq,
Scalar = Self::Fr,
Affine = Self::G1Affine,
>
+ From<Self::G1Affine>;
/// The affine representation of an element in G1.
type G1Affine: CurveAffine<
Engine = Self,
Base = Self::Fq,
Scalar = Self::Fr,
Projective = Self::G1,
Pair = Self::G2Affine,
PairingResult = Self::Fqk,
>
+ From<Self::G1>;
/// The projective representation of an element in G2.
type G2: CurveProjective<
Engine = Self,
Base = Self::Fqe,
Scalar = Self::Fr,
Affine = Self::G2Affine,
>
+ From<Self::G2Affine>;
/// The affine representation of an element in G2.
type G2Affine: CurveAffine<
Engine = Self,
Base = Self::Fqe,
Scalar = Self::Fr,
Projective = Self::G2,
Pair = Self::G1Affine,
PairingResult = Self::Fqk,
>
+ From<Self::G2>;
/// The base field that hosts G1.
type Fq: PrimeField + SqrtField;
/// The extension field that hosts G2.
type Fqe: SqrtField;
/// The extension field that hosts the target group of the pairing.
type Fqk: Field;
/// Perform a miller loop with some number of (G1, G2) pairs.
fn miller_loop<'a, I>(i: I) -> Self::Fqk
where
I: IntoIterator<
Item = &'a (
&'a <Self::G1Affine as CurveAffine>::Prepared,
&'a <Self::G2Affine as CurveAffine>::Prepared,
),
>;
/// Perform final exponentiation of the result of a miller loop.
fn final_exponentiation(&Self::Fqk) -> Option<Self::Fqk>;
/// Performs a complete pairing operation `(p, q)`.
fn pairing<G1, G2>(p: G1, q: G2) -> Self::Fqk
where
G1: Into<Self::G1Affine>,
G2: Into<Self::G2Affine>,
{
Self::final_exponentiation(&Self::miller_loop(
[(&(p.into().prepare()), &(q.into().prepare()))].into_iter(),
)).unwrap()
}
}
/// Projective representation of an elliptic curve point guaranteed to be
/// in the correct prime order subgroup.
pub trait CurveProjective:
PartialEq
+ Eq
+ Sized
+ Copy
+ Clone
+ Send
+ Sync
+ fmt::Debug
+ fmt::Display
+ rand::Rand
+ 'static
{
type Engine: Engine<Fr = Self::Scalar>;
type Scalar: PrimeField + SqrtField;
type Base: SqrtField;
type Affine: CurveAffine<Projective = Self, Scalar = Self::Scalar>;
/// Returns the additive identity.
fn zero() -> Self;
/// Returns a fixed generator of unknown exponent.
fn one() -> Self;
/// Determines if this point is the point at infinity.
fn is_zero(&self) -> bool;
/// Normalizes a slice of projective elements so that
/// conversion to affine is cheap.
fn batch_normalization(v: &mut [Self]);
/// Checks if the point is already "normalized" so that
/// cheap affine conversion is possible.
fn is_normalized(&self) -> bool;
/// Doubles this element.
fn double(&mut self);
/// Adds another element to this element.
fn add_assign(&mut self, other: &Self);
/// Subtracts another element from this element.
fn sub_assign(&mut self, other: &Self) {
let mut tmp = *other;
tmp.negate();
self.add_assign(&tmp);
}
/// Adds an affine element to this element.
fn add_assign_mixed(&mut self, other: &Self::Affine);
/// Negates this element.
fn negate(&mut self);
/// Performs scalar multiplication of this element.
fn mul_assign<S: Into<<Self::Scalar as PrimeField>::Repr>>(&mut self, other: S);
/// Converts this element into its affine representation.
fn into_affine(&self) -> Self::Affine;
/// Recommends a wNAF window table size given a scalar. Always returns a number
/// between 2 and 22, inclusive.
fn recommended_wnaf_for_scalar(scalar: <Self::Scalar as PrimeField>::Repr) -> usize;
/// Recommends a wNAF window size given the number of scalars you intend to multiply
/// a base by. Always returns a number between 2 and 22, inclusive.
fn recommended_wnaf_for_num_scalars(num_scalars: usize) -> usize;
}
/// Affine representation of an elliptic curve point guaranteed to be
/// in the correct prime order subgroup.
pub trait CurveAffine:
Copy + Clone + Sized + Send + Sync + fmt::Debug + fmt::Display + PartialEq + Eq + 'static
{
type Engine: Engine<Fr = Self::Scalar>;
type Scalar: PrimeField + SqrtField;
type Base: SqrtField;
type Projective: CurveProjective<Affine = Self, Scalar = Self::Scalar>;
type Prepared: Clone + Send + Sync + 'static;
type Uncompressed: EncodedPoint<Affine = Self>;
type Compressed: EncodedPoint<Affine = Self>;
type Pair: CurveAffine<Pair = Self>;
type PairingResult: Field;
/// Returns the additive identity.
fn zero() -> Self;
/// Returns a fixed generator of unknown exponent.
fn one() -> Self;
/// Determines if this point represents the point at infinity; the
/// additive identity.
fn is_zero(&self) -> bool;
/// Negates this element.
fn negate(&mut self);
/// Performs scalar multiplication of this element with mixed addition.
fn mul<S: Into<<Self::Scalar as PrimeField>::Repr>>(&self, other: S) -> Self::Projective;
/// Prepares this element for pairing purposes.
fn prepare(&self) -> Self::Prepared;
/// Perform a pairing
fn pairing_with(&self, other: &Self::Pair) -> Self::PairingResult;
/// Converts this element into its affine representation.
fn into_projective(&self) -> Self::Projective;
/// Converts this element into its compressed encoding, so long as it's not
/// the point at infinity.
fn into_compressed(&self) -> Self::Compressed {
<Self::Compressed as EncodedPoint>::from_affine(*self)
}
/// Converts this element into its uncompressed encoding, so long as it's not
/// the point at infinity.
fn into_uncompressed(&self) -> Self::Uncompressed {
<Self::Uncompressed as EncodedPoint>::from_affine(*self)
}
}
/// An encoded elliptic curve point, which should essentially wrap a `[u8; N]`.
pub trait EncodedPoint:
Sized + Send + Sync + AsRef<[u8]> + AsMut<[u8]> + Clone + Copy + 'static
{
type Affine: CurveAffine;
/// Creates an empty representation.
fn empty() -> Self;
/// Returns the number of bytes consumed by this representation.
fn size() -> usize;
/// Converts an `EncodedPoint` into a `CurveAffine` element,
/// if the encoding represents a valid element.
fn into_affine(&self) -> Result<Self::Affine, GroupDecodingError>;
/// Converts an `EncodedPoint` into a `CurveAffine` element,
/// without guaranteeing that the encoding represents a valid
/// element. This is useful when the caller knows the encoding is
/// valid already.
///
/// If the encoding is invalid, this can break API invariants,
/// so caution is strongly encouraged.
fn into_affine_unchecked(&self) -> Result<Self::Affine, GroupDecodingError>;
/// Creates an `EncodedPoint` from an affine point, as long as the
/// point is not the point at infinity.
fn from_affine(affine: Self::Affine) -> Self;
}
/// This trait represents an element of a field.
pub trait Field:
Sized + Eq + Copy + Clone + Send + Sync + fmt::Debug + fmt::Display + 'static + rand::Rand
{
/// Returns the zero element of the field, the additive identity.
fn zero() -> Self;
/// Returns the one element of the field, the multiplicative identity.
fn one() -> Self;
/// Returns true iff this element is zero.
fn is_zero(&self) -> bool;
/// Squares this element.
fn square(&mut self);
/// Doubles this element.
fn double(&mut self);
/// Negates this element.
fn negate(&mut self);
/// Adds another element to this element.
fn add_assign(&mut self, other: &Self);
/// Subtracts another element from this element.
fn sub_assign(&mut self, other: &Self);
/// Multiplies another element by this element.
fn mul_assign(&mut self, other: &Self);
/// Computes the multiplicative inverse of this element, if nonzero.
fn inverse(&self) -> Option<Self>;
/// Exponentiates this element by a power of the base prime modulus via
/// the Frobenius automorphism.
fn frobenius_map(&mut self, power: usize);
/// Exponentiates this element by a number represented with `u64` limbs,
/// least significant digit first.
fn pow<S: AsRef<[u64]>>(&self, exp: S) -> Self {
let mut res = Self::one();
let mut found_one = false;
for i in BitIterator::new(exp) {
if found_one {
res.square();
} else {
found_one = i;
}
if i {
res.mul_assign(self);
}
}
res
}
}
/// This trait represents an element of a field that has a square root operation described for it.
pub trait SqrtField: Field {
/// Returns the Legendre symbol of the field element.
fn legendre(&self) -> LegendreSymbol;
/// Returns the square root of the field element, if it is
/// quadratic residue.
fn sqrt(&self) -> Option<Self>;
}
/// This trait represents a wrapper around a biginteger which can encode any element of a particular
/// prime field. It is a smart wrapper around a sequence of `u64` limbs, least-significant digit
/// first.
pub trait PrimeFieldRepr:
Sized
+ Copy
+ Clone
+ Eq
+ Ord
+ Send
+ Sync
+ Default
+ fmt::Debug
+ fmt::Display
+ 'static
+ rand::Rand
+ AsRef<[u64]>
+ AsMut<[u64]>
+ From<u64>
{
/// Subtract another represetation from this one.
fn sub_noborrow(&mut self, other: &Self);
/// Add another representation to this one.
fn add_nocarry(&mut self, other: &Self);
/// Compute the number of bits needed to encode this number. Always a
/// multiple of 64.
fn num_bits(&self) -> u32;
/// Returns true iff this number is zero.
fn is_zero(&self) -> bool;
/// Returns true iff this number is odd.
fn is_odd(&self) -> bool;
/// Returns true iff this number is even.
fn is_even(&self) -> bool;
/// Performs a rightwise bitshift of this number, effectively dividing
/// it by 2.
fn div2(&mut self);
/// Performs a rightwise bitshift of this number by some amount.
fn shr(&mut self, amt: u32);
/// Performs a leftwise bitshift of this number, effectively multiplying
/// it by 2. Overflow is ignored.
fn mul2(&mut self);
/// Performs a leftwise bitshift of this number by some amount.
fn shl(&mut self, amt: u32);
/// Writes this `PrimeFieldRepr` as a big endian integer.
fn write_be<W: Write>(&self, mut writer: W) -> io::Result<()> {
use byteorder::{BigEndian, WriteBytesExt};
for digit in self.as_ref().iter().rev() {
writer.write_u64::<BigEndian>(*digit)?;
}
Ok(())
}
/// Reads a big endian integer into this representation.
fn read_be<R: Read>(&mut self, mut reader: R) -> io::Result<()> {
use byteorder::{BigEndian, ReadBytesExt};
for digit in self.as_mut().iter_mut().rev() {
*digit = reader.read_u64::<BigEndian>()?;
}
Ok(())
}
/// Writes this `PrimeFieldRepr` as a little endian integer.
fn write_le<W: Write>(&self, mut writer: W) -> io::Result<()> {
use byteorder::{LittleEndian, WriteBytesExt};
for digit in self.as_ref().iter() {
writer.write_u64::<LittleEndian>(*digit)?;
}
Ok(())
}
/// Reads a little endian integer into this representation.
fn read_le<R: Read>(&mut self, mut reader: R) -> io::Result<()> {
use byteorder::{LittleEndian, ReadBytesExt};
for digit in self.as_mut().iter_mut() {
*digit = reader.read_u64::<LittleEndian>()?;
}
Ok(())
}
}
#[derive(Debug, PartialEq)]
pub enum LegendreSymbol {
Zero = 0,
QuadraticResidue = 1,
QuadraticNonResidue = -1,
}
/// An error that may occur when trying to interpret a `PrimeFieldRepr` as a
/// `PrimeField` element.
#[derive(Debug)]
pub enum PrimeFieldDecodingError {
/// The encoded value is not in the field
NotInField(String),
}
impl Error for PrimeFieldDecodingError {
fn description(&self) -> &str {
match *self {
PrimeFieldDecodingError::NotInField(..) => "not an element of the field",
}
}
}
impl fmt::Display for PrimeFieldDecodingError {
fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
match *self {
PrimeFieldDecodingError::NotInField(ref repr) => {
write!(f, "{} is not an element of the field", repr)
}
}
}
}
/// An error that may occur when trying to decode an `EncodedPoint`.
#[derive(Debug)]
pub enum GroupDecodingError {
/// The coordinate(s) do not lie on the curve.
NotOnCurve,
/// The element is not part of the r-order subgroup.
NotInSubgroup,
/// One of the coordinates could not be decoded
CoordinateDecodingError(&'static str, PrimeFieldDecodingError),
/// The compression mode of the encoded element was not as expected
UnexpectedCompressionMode,
/// The encoding contained bits that should not have been set
UnexpectedInformation,
}
impl Error for GroupDecodingError {
fn description(&self) -> &str {
match *self {
GroupDecodingError::NotOnCurve => "coordinate(s) do not lie on the curve",
GroupDecodingError::NotInSubgroup => "the element is not part of an r-order subgroup",
GroupDecodingError::CoordinateDecodingError(..) => "coordinate(s) could not be decoded",
GroupDecodingError::UnexpectedCompressionMode => {
"encoding has unexpected compression mode"
}
GroupDecodingError::UnexpectedInformation => "encoding has unexpected information",
}
}
}
impl fmt::Display for GroupDecodingError {
fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
match *self {
GroupDecodingError::CoordinateDecodingError(description, ref err) => {
write!(f, "{} decoding error: {}", description, err)
}
_ => write!(f, "{}", self.description()),
}
}
}
/// This represents an element of a prime field.
pub trait PrimeField: Field {
/// The prime field can be converted back and forth into this biginteger
/// representation.
type Repr: PrimeFieldRepr + From<Self>;
/// Interpret a string of numbers as a (congruent) prime field element.
/// Does not accept unnecessary leading zeroes or a blank string.
fn from_str(s: &str) -> Option<Self> {
if s.is_empty() {
return None;
}
if s == "0" {
return Some(Self::zero());
}
let mut res = Self::zero();
let ten = Self::from_repr(Self::Repr::from(10)).unwrap();
let mut first_digit = true;
for c in s.chars() {
match c.to_digit(10) {
Some(c) => {
if first_digit {
if c == 0 {
return None;
}
first_digit = false;
}
res.mul_assign(&ten);
res.add_assign(&Self::from_repr(Self::Repr::from(u64::from(c))).unwrap());
}
None => {
return None;
}
}
}
Some(res)
}
/// Convert this prime field element into a biginteger representation.
fn from_repr(Self::Repr) -> Result<Self, PrimeFieldDecodingError>;
/// Convert a biginteger representation into a prime field element, if
/// the number is an element of the field.
fn into_repr(&self) -> Self::Repr;
/// Returns the field characteristic; the modulus.
fn char() -> Self::Repr;
/// How many bits are needed to represent an element of this field.
const NUM_BITS: u32;
/// How many bits of information can be reliably stored in the field element.
const CAPACITY: u32;
/// Returns the multiplicative generator of `char()` - 1 order. This element
/// must also be quadratic nonresidue.
fn multiplicative_generator() -> Self;
/// 2^s * t = `char()` - 1 with t odd.
const S: u32;
/// Returns the 2^s root of unity computed by exponentiating the `multiplicative_generator()`
/// by t.
fn root_of_unity() -> Self;
}
#[derive(Debug)]
pub struct BitIterator<E> {
t: E,
n: usize,
}
impl<E: AsRef<[u64]>> BitIterator<E> {
pub fn new(t: E) -> Self {
let n = t.as_ref().len() * 64;
BitIterator { t, n }
}
}
impl<E: AsRef<[u64]>> Iterator for BitIterator<E> {
type Item = bool;
fn next(&mut self) -> Option<bool> {
if self.n == 0 {
None
} else {
self.n -= 1;
let part = self.n / 64;
let bit = self.n - (64 * part);
Some(self.t.as_ref()[part] & (1 << bit) > 0)
}
}
}
#[test]
fn test_bit_iterator() {
let mut a = BitIterator::new([0xa953d79b83f6ab59, 0x6dea2059e200bd39]);
let expected = "01101101111010100010000001011001111000100000000010111101001110011010100101010011110101111001101110000011111101101010101101011001";
for e in expected.chars() {
assert!(a.next().unwrap() == (e == '1'));
}
assert!(a.next().is_none());
let expected = "1010010101111110101010000101101011101000011101110101001000011001100100100011011010001011011011010001011011101100110100111011010010110001000011110100110001100110011101101000101100011100100100100100001010011101010111110011101011000011101000111011011101011001";
let mut a = BitIterator::new([
0x429d5f3ac3a3b759,
0xb10f4c66768b1c92,
0x92368b6d16ecd3b4,
0xa57ea85ae8775219,
]);
for e in expected.chars() {
assert!(a.next().unwrap() == (e == '1'));
}
assert!(a.next().is_none());
}
#[cfg(not(feature = "expose-arith"))]
use self::arith_impl::*;
#[cfg(feature = "expose-arith")]
pub use self::arith_impl::*;
#[cfg(feature = "u128-support")]
mod arith_impl {
/// Calculate a - b - borrow, returning the result and modifying
/// the borrow value.
#[inline(always)]
pub fn sbb(a: u64, b: u64, borrow: &mut u64) -> u64 {
let tmp = (1u128 << 64) + u128::from(a) - u128::from(b) - u128::from(*borrow);
*borrow = if tmp >> 64 == 0 { 1 } else { 0 };
tmp as u64
}
/// Calculate a + b + carry, returning the sum and modifying the
/// carry value.
#[inline(always)]
pub fn adc(a: u64, b: u64, carry: &mut u64) -> u64 {
let tmp = u128::from(a) + u128::from(b) + u128::from(*carry);
*carry = (tmp >> 64) as u64;
tmp as u64
}
/// Calculate a + (b * c) + carry, returning the least significant digit
/// and setting carry to the most significant digit.
#[inline(always)]
pub fn mac_with_carry(a: u64, b: u64, c: u64, carry: &mut u64) -> u64 {
let tmp = (u128::from(a)) + u128::from(b) * u128::from(c) + u128::from(*carry);
*carry = (tmp >> 64) as u64;
tmp as u64
}
}
#[cfg(not(feature = "u128-support"))]
mod arith_impl {
#[inline(always)]
fn split_u64(i: u64) -> (u64, u64) {
(i >> 32, i & 0xFFFFFFFF)
}
#[inline(always)]
fn combine_u64(hi: u64, lo: u64) -> u64 {
(hi << 32) | lo
}
/// Calculate a - b - borrow, returning the result and modifying
/// the borrow value.
#[inline(always)]
pub fn sbb(a: u64, b: u64, borrow: &mut u64) -> u64 {
let (a_hi, a_lo) = split_u64(a);
let (b_hi, b_lo) = split_u64(b);
let (b, r0) = split_u64((1 << 32) + a_lo - b_lo - *borrow);
let (b, r1) = split_u64((1 << 32) + a_hi - b_hi - ((b == 0) as u64));
*borrow = (b == 0) as u64;
combine_u64(r1, r0)
}
/// Calculate a + b + carry, returning the sum and modifying the
/// carry value.
#[inline(always)]
pub fn adc(a: u64, b: u64, carry: &mut u64) -> u64 {
let (a_hi, a_lo) = split_u64(a);
let (b_hi, b_lo) = split_u64(b);
let (carry_hi, carry_lo) = split_u64(*carry);
let (t, r0) = split_u64(a_lo + b_lo + carry_lo);
let (t, r1) = split_u64(t + a_hi + b_hi + carry_hi);
*carry = t;
combine_u64(r1, r0)
}
/// Calculate a + (b * c) + carry, returning the least significant digit
/// and setting carry to the most significant digit.
#[inline(always)]
pub fn mac_with_carry(a: u64, b: u64, c: u64, carry: &mut u64) -> u64 {
/*
[ b_hi | b_lo ]
[ c_hi | c_lo ] *
-------------------------------------------
[ b_lo * c_lo ] <-- w
[ b_hi * c_lo ] <-- x
[ b_lo * c_hi ] <-- y
[ b_hi * c_lo ] <-- z
[ a_hi | a_lo ]
[ C_hi | C_lo ]
*/
let (a_hi, a_lo) = split_u64(a);
let (b_hi, b_lo) = split_u64(b);
let (c_hi, c_lo) = split_u64(c);
let (carry_hi, carry_lo) = split_u64(*carry);
let (w_hi, w_lo) = split_u64(b_lo * c_lo);
let (x_hi, x_lo) = split_u64(b_hi * c_lo);
let (y_hi, y_lo) = split_u64(b_lo * c_hi);
let (z_hi, z_lo) = split_u64(b_hi * c_hi);
let (t, r0) = split_u64(w_lo + a_lo + carry_lo);
let (t, r1) = split_u64(t + w_hi + x_lo + y_lo + a_hi + carry_hi);
let (t, r2) = split_u64(t + x_hi + y_hi + z_lo);
let (_, r3) = split_u64(t + z_hi);
*carry = combine_u64(r3, r2);
combine_u64(r1, r0)
}
}

420
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use rand::{Rand, Rng, SeedableRng, XorShiftRng};
use {CurveAffine, CurveProjective, EncodedPoint, Field};
pub fn curve_tests<G: CurveProjective>() {
let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
// Negation edge case with zero.
{
let mut z = G::zero();
z.negate();
assert!(z.is_zero());
}
// Doubling edge case with zero.
{
let mut z = G::zero();
z.double();
assert!(z.is_zero());
}
// Addition edge cases with zero
{
let mut r = G::rand(&mut rng);
let rcopy = r;
r.add_assign(&G::zero());
assert_eq!(r, rcopy);
r.add_assign_mixed(&G::Affine::zero());
assert_eq!(r, rcopy);
let mut z = G::zero();
z.add_assign(&G::zero());
assert!(z.is_zero());
z.add_assign_mixed(&G::Affine::zero());
assert!(z.is_zero());
let mut z2 = z;
z2.add_assign(&r);
z.add_assign_mixed(&r.into_affine());
assert_eq!(z, z2);
assert_eq!(z, r);
}
// Transformations
{
let a = G::rand(&mut rng);
let b = a.into_affine().into_projective();
let c = a
.into_affine()
.into_projective()
.into_affine()
.into_projective();
assert_eq!(a, b);
assert_eq!(b, c);
}
random_addition_tests::<G>();
random_multiplication_tests::<G>();
random_doubling_tests::<G>();
random_negation_tests::<G>();
random_transformation_tests::<G>();
random_wnaf_tests::<G>();
random_encoding_tests::<G::Affine>();
}
fn random_wnaf_tests<G: CurveProjective>() {
use wnaf::*;
use PrimeField;
let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
{
let mut table = vec![];
let mut wnaf = vec![];
for w in 2..14 {
for _ in 0..100 {
let g = G::rand(&mut rng);
let s = G::Scalar::rand(&mut rng).into_repr();
let mut g1 = g;
g1.mul_assign(s);
wnaf_table(&mut table, g, w);
wnaf_form(&mut wnaf, s, w);
let g2 = wnaf_exp(&table, &wnaf);
assert_eq!(g1, g2);
}
}
}
{
fn only_compiles_if_send<S: Send>(_: &S) {}
for _ in 0..100 {
let g = G::rand(&mut rng);
let s = G::Scalar::rand(&mut rng).into_repr();
let mut g1 = g;
g1.mul_assign(s);
let g2 = {
let mut wnaf = Wnaf::new();
wnaf.base(g, 1).scalar(s)
};
let g3 = {
let mut wnaf = Wnaf::new();
wnaf.scalar(s).base(g)
};
let g4 = {
let mut wnaf = Wnaf::new();
let mut shared = wnaf.base(g, 1).shared();
only_compiles_if_send(&shared);
shared.scalar(s)
};
let g5 = {
let mut wnaf = Wnaf::new();
let mut shared = wnaf.scalar(s).shared();
only_compiles_if_send(&shared);
shared.base(g)
};
let g6 = {
let mut wnaf = Wnaf::new();
{
// Populate the vectors.
wnaf.base(rng.gen(), 1).scalar(rng.gen());
}
wnaf.base(g, 1).scalar(s)
};
let g7 = {
let mut wnaf = Wnaf::new();
{
// Populate the vectors.
wnaf.base(rng.gen(), 1).scalar(rng.gen());
}
wnaf.scalar(s).base(g)
};
let g8 = {
let mut wnaf = Wnaf::new();
{
// Populate the vectors.
wnaf.base(rng.gen(), 1).scalar(rng.gen());
}
let mut shared = wnaf.base(g, 1).shared();
only_compiles_if_send(&shared);
shared.scalar(s)
};
let g9 = {
let mut wnaf = Wnaf::new();
{
// Populate the vectors.
wnaf.base(rng.gen(), 1).scalar(rng.gen());
}
let mut shared = wnaf.scalar(s).shared();
only_compiles_if_send(&shared);
shared.base(g)
};
assert_eq!(g1, g2);
assert_eq!(g1, g3);
assert_eq!(g1, g4);
assert_eq!(g1, g5);
assert_eq!(g1, g6);
assert_eq!(g1, g7);
assert_eq!(g1, g8);
assert_eq!(g1, g9);
}
}
}
fn random_negation_tests<G: CurveProjective>() {
let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
for _ in 0..1000 {
let r = G::rand(&mut rng);
let s = G::Scalar::rand(&mut rng);
let mut sneg = s;
sneg.negate();
let mut t1 = r;
t1.mul_assign(s);
let mut t2 = r;
t2.mul_assign(sneg);
let mut t3 = t1;
t3.add_assign(&t2);
assert!(t3.is_zero());
let mut t4 = t1;
t4.add_assign_mixed(&t2.into_affine());
assert!(t4.is_zero());
t1.negate();
assert_eq!(t1, t2);
}
}
fn random_doubling_tests<G: CurveProjective>() {
let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
for _ in 0..1000 {
let mut a = G::rand(&mut rng);
let mut b = G::rand(&mut rng);
// 2(a + b)
let mut tmp1 = a;
tmp1.add_assign(&b);
tmp1.double();
// 2a + 2b
a.double();
b.double();
let mut tmp2 = a;
tmp2.add_assign(&b);
let mut tmp3 = a;
tmp3.add_assign_mixed(&b.into_affine());
assert_eq!(tmp1, tmp2);
assert_eq!(tmp1, tmp3);
}
}
fn random_multiplication_tests<G: CurveProjective>() {
let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
for _ in 0..1000 {
let mut a = G::rand(&mut rng);
let mut b = G::rand(&mut rng);
let a_affine = a.into_affine();
let b_affine = b.into_affine();
let s = G::Scalar::rand(&mut rng);
// s ( a + b )
let mut tmp1 = a;
tmp1.add_assign(&b);
tmp1.mul_assign(s);
// sa + sb
a.mul_assign(s);
b.mul_assign(s);
let mut tmp2 = a;
tmp2.add_assign(&b);
// Affine multiplication
let mut tmp3 = a_affine.mul(s);
tmp3.add_assign(&b_affine.mul(s));
assert_eq!(tmp1, tmp2);
assert_eq!(tmp1, tmp3);
}
}
fn random_addition_tests<G: CurveProjective>() {
let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
for _ in 0..1000 {
let a = G::rand(&mut rng);
let b = G::rand(&mut rng);
let c = G::rand(&mut rng);
let a_affine = a.into_affine();
let b_affine = b.into_affine();
let c_affine = c.into_affine();
// a + a should equal the doubling
{
let mut aplusa = a;
aplusa.add_assign(&a);
let mut aplusamixed = a;
aplusamixed.add_assign_mixed(&a.into_affine());
let mut adouble = a;
adouble.double();
assert_eq!(aplusa, adouble);
assert_eq!(aplusa, aplusamixed);
}
let mut tmp = vec![G::zero(); 6];
// (a + b) + c
tmp[0] = a;
tmp[0].add_assign(&b);
tmp[0].add_assign(&c);
// a + (b + c)
tmp[1] = b;
tmp[1].add_assign(&c);
tmp[1].add_assign(&a);
// (a + c) + b
tmp[2] = a;
tmp[2].add_assign(&c);
tmp[2].add_assign(&b);
// Mixed addition
// (a + b) + c
tmp[3] = a_affine.into_projective();
tmp[3].add_assign_mixed(&b_affine);
tmp[3].add_assign_mixed(&c_affine);
// a + (b + c)
tmp[4] = b_affine.into_projective();
tmp[4].add_assign_mixed(&c_affine);
tmp[4].add_assign_mixed(&a_affine);
// (a + c) + b
tmp[5] = a_affine.into_projective();
tmp[5].add_assign_mixed(&c_affine);
tmp[5].add_assign_mixed(&b_affine);
// Comparisons
for i in 0..6 {
for j in 0..6 {
assert_eq!(tmp[i], tmp[j]);
assert_eq!(tmp[i].into_affine(), tmp[j].into_affine());
}
assert!(tmp[i] != a);
assert!(tmp[i] != b);
assert!(tmp[i] != c);
assert!(a != tmp[i]);
assert!(b != tmp[i]);
assert!(c != tmp[i]);
}
}
}
fn random_transformation_tests<G: CurveProjective>() {
let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
for _ in 0..1000 {
let g = G::rand(&mut rng);
let g_affine = g.into_affine();
let g_projective = g_affine.into_projective();
assert_eq!(g, g_projective);
}
// Batch normalization
for _ in 0..10 {
let mut v = (0..1000).map(|_| G::rand(&mut rng)).collect::<Vec<_>>();
for i in &v {
assert!(!i.is_normalized());
}
use rand::distributions::{IndependentSample, Range};
let between = Range::new(0, 1000);
// Sprinkle in some normalized points
for _ in 0..5 {
v[between.ind_sample(&mut rng)] = G::zero();
}
for _ in 0..5 {
let s = between.ind_sample(&mut rng);
v[s] = v[s].into_affine().into_projective();
}
let expected_v = v
.iter()
.map(|v| v.into_affine().into_projective())
.collect::<Vec<_>>();
G::batch_normalization(&mut v);
for i in &v {
assert!(i.is_normalized());
}
assert_eq!(v, expected_v);
}
}
fn random_encoding_tests<G: CurveAffine>() {
let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
assert_eq!(
G::zero().into_uncompressed().into_affine().unwrap(),
G::zero()
);
assert_eq!(
G::zero().into_compressed().into_affine().unwrap(),
G::zero()
);
for _ in 0..1000 {
let mut r = G::Projective::rand(&mut rng).into_affine();
let uncompressed = r.into_uncompressed();
let de_uncompressed = uncompressed.into_affine().unwrap();
assert_eq!(de_uncompressed, r);
let compressed = r.into_compressed();
let de_compressed = compressed.into_affine().unwrap();
assert_eq!(de_compressed, r);
r.negate();
let compressed = r.into_compressed();
let de_compressed = compressed.into_affine().unwrap();
assert_eq!(de_compressed, r);
}
}

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use rand::{Rand, SeedableRng, XorShiftRng};
use {CurveAffine, CurveProjective, Engine, Field, PrimeField};
pub fn engine_tests<E: Engine>() {
let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
for _ in 0..10 {
let a = E::G1::rand(&mut rng).into_affine();
let b = E::G2::rand(&mut rng).into_affine();
assert!(a.pairing_with(&b) == b.pairing_with(&a));
assert!(a.pairing_with(&b) == E::pairing(a, b));
}
for _ in 0..1000 {
let z1 = E::G1Affine::zero().prepare();
let z2 = E::G2Affine::zero().prepare();
let a = E::G1::rand(&mut rng).into_affine().prepare();
let b = E::G2::rand(&mut rng).into_affine().prepare();
let c = E::G1::rand(&mut rng).into_affine().prepare();
let d = E::G2::rand(&mut rng).into_affine().prepare();
assert_eq!(
E::Fqk::one(),
E::final_exponentiation(&E::miller_loop(&[(&z1, &b)])).unwrap()
);
assert_eq!(
E::Fqk::one(),
E::final_exponentiation(&E::miller_loop(&[(&a, &z2)])).unwrap()
);
assert_eq!(
E::final_exponentiation(&E::miller_loop(&[(&z1, &b), (&c, &d)])).unwrap(),
E::final_exponentiation(&E::miller_loop(&[(&a, &z2), (&c, &d)])).unwrap()
);
assert_eq!(
E::final_exponentiation(&E::miller_loop(&[(&a, &b), (&z1, &d)])).unwrap(),
E::final_exponentiation(&E::miller_loop(&[(&a, &b), (&c, &z2)])).unwrap()
);
}
random_bilinearity_tests::<E>();
random_miller_loop_tests::<E>();
}
fn random_miller_loop_tests<E: Engine>() {
let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
// Exercise the miller loop for a reduced pairing
for _ in 0..1000 {
let a = E::G1::rand(&mut rng);
let b = E::G2::rand(&mut rng);
let p2 = E::pairing(a, b);
let a = a.into_affine().prepare();
let b = b.into_affine().prepare();
let p1 = E::final_exponentiation(&E::miller_loop(&[(&a, &b)])).unwrap();
assert_eq!(p1, p2);
}
// Exercise a double miller loop
for _ in 0..1000 {
let a = E::G1::rand(&mut rng);
let b = E::G2::rand(&mut rng);
let c = E::G1::rand(&mut rng);
let d = E::G2::rand(&mut rng);
let ab = E::pairing(a, b);
let cd = E::pairing(c, d);
let mut abcd = ab;
abcd.mul_assign(&cd);
let a = a.into_affine().prepare();
let b = b.into_affine().prepare();
let c = c.into_affine().prepare();
let d = d.into_affine().prepare();
let abcd_with_double_loop =
E::final_exponentiation(&E::miller_loop(&[(&a, &b), (&c, &d)])).unwrap();
assert_eq!(abcd, abcd_with_double_loop);
}
}
fn random_bilinearity_tests<E: Engine>() {
let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
for _ in 0..1000 {
let a = E::G1::rand(&mut rng);
let b = E::G2::rand(&mut rng);
let c = E::Fr::rand(&mut rng);
let d = E::Fr::rand(&mut rng);
let mut ac = a;
ac.mul_assign(c);
let mut ad = a;
ad.mul_assign(d);
let mut bc = b;
bc.mul_assign(c);
let mut bd = b;
bd.mul_assign(d);
let acbd = E::pairing(ac, bd);
let adbc = E::pairing(ad, bc);
let mut cd = c;
cd.mul_assign(&d);
let abcd = E::pairing(a, b).pow(cd.into_repr());
assert_eq!(acbd, adbc);
assert_eq!(acbd, abcd);
}
}

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use rand::{Rng, SeedableRng, XorShiftRng};
use {Field, LegendreSymbol, PrimeField, SqrtField};
pub fn random_frobenius_tests<F: Field, C: AsRef<[u64]>>(characteristic: C, maxpower: usize) {
let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
for _ in 0..100 {
for i in 0..(maxpower + 1) {
let mut a = F::rand(&mut rng);
let mut b = a;
for _ in 0..i {
a = a.pow(&characteristic);
}
b.frobenius_map(i);
assert_eq!(a, b);
}
}
}
pub fn random_sqrt_tests<F: SqrtField>() {
let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
for _ in 0..10000 {
let a = F::rand(&mut rng);
let mut b = a;
b.square();
assert_eq!(b.legendre(), LegendreSymbol::QuadraticResidue);
let b = b.sqrt().unwrap();
let mut negb = b;
negb.negate();
assert!(a == b || a == negb);
}
let mut c = F::one();
for _ in 0..10000 {
let mut b = c;
b.square();
assert_eq!(b.legendre(), LegendreSymbol::QuadraticResidue);
b = b.sqrt().unwrap();
if b != c {
b.negate();
}
assert_eq!(b, c);
c.add_assign(&F::one());
}
}
pub fn random_field_tests<F: Field>() {
let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
random_multiplication_tests::<F, _>(&mut rng);
random_addition_tests::<F, _>(&mut rng);
random_subtraction_tests::<F, _>(&mut rng);
random_negation_tests::<F, _>(&mut rng);
random_doubling_tests::<F, _>(&mut rng);
random_squaring_tests::<F, _>(&mut rng);
random_inversion_tests::<F, _>(&mut rng);
random_expansion_tests::<F, _>(&mut rng);
assert!(F::zero().is_zero());
{
let mut z = F::zero();
z.negate();
assert!(z.is_zero());
}
assert!(F::zero().inverse().is_none());
// Multiplication by zero
{
let mut a = F::rand(&mut rng);
a.mul_assign(&F::zero());
assert!(a.is_zero());
}
// Addition by zero
{
let mut a = F::rand(&mut rng);
let copy = a;
a.add_assign(&F::zero());
assert_eq!(a, copy);
}
}
pub fn from_str_tests<F: PrimeField>() {
{
let a = "84395729384759238745923745892374598234705297301958723458712394587103249587213984572934750213947582345792304758273458972349582734958273495872304598234";
let b = "38495729084572938457298347502349857029384609283450692834058293405982304598230458230495820394850293845098234059823049582309485203948502938452093482039";
let c = "3248875134290623212325429203829831876024364170316860259933542844758450336418538569901990710701240661702808867062612075657861768196242274635305077449545396068598317421057721935408562373834079015873933065667961469731886739181625866970316226171512545167081793907058686908697431878454091011239990119126";
let mut a = F::from_str(a).unwrap();
let b = F::from_str(b).unwrap();
let c = F::from_str(c).unwrap();
a.mul_assign(&b);
assert_eq!(a, c);
}
{
let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
for _ in 0..1000 {
let n: u64 = rng.gen();
let a = F::from_str(&format!("{}", n)).unwrap();
let b = F::from_repr(n.into()).unwrap();
assert_eq!(a, b);
}
}
assert!(F::from_str("").is_none());
assert!(F::from_str("0").unwrap().is_zero());
assert!(F::from_str("00").is_none());
assert!(F::from_str("00000000000").is_none());
}
fn random_multiplication_tests<F: Field, R: Rng>(rng: &mut R) {
for _ in 0..10000 {
let a = F::rand(rng);
let b = F::rand(rng);
let c = F::rand(rng);
let mut t0 = a; // (a * b) * c
t0.mul_assign(&b);
t0.mul_assign(&c);
let mut t1 = a; // (a * c) * b
t1.mul_assign(&c);
t1.mul_assign(&b);
let mut t2 = b; // (b * c) * a
t2.mul_assign(&c);
t2.mul_assign(&a);
assert_eq!(t0, t1);
assert_eq!(t1, t2);
}
}
fn random_addition_tests<F: Field, R: Rng>(rng: &mut R) {
for _ in 0..10000 {
let a = F::rand(rng);
let b = F::rand(rng);
let c = F::rand(rng);
let mut t0 = a; // (a + b) + c
t0.add_assign(&b);
t0.add_assign(&c);
let mut t1 = a; // (a + c) + b
t1.add_assign(&c);
t1.add_assign(&b);
let mut t2 = b; // (b + c) + a
t2.add_assign(&c);
t2.add_assign(&a);
assert_eq!(t0, t1);
assert_eq!(t1, t2);
}
}
fn random_subtraction_tests<F: Field, R: Rng>(rng: &mut R) {
for _ in 0..10000 {
let a = F::rand(rng);
let b = F::rand(rng);
let mut t0 = a; // (a - b)
t0.sub_assign(&b);
let mut t1 = b; // (b - a)
t1.sub_assign(&a);
let mut t2 = t0; // (a - b) + (b - a) = 0
t2.add_assign(&t1);
assert!(t2.is_zero());
}
}
fn random_negation_tests<F: Field, R: Rng>(rng: &mut R) {
for _ in 0..10000 {
let a = F::rand(rng);
let mut b = a;
b.negate();
b.add_assign(&a);
assert!(b.is_zero());
}
}
fn random_doubling_tests<F: Field, R: Rng>(rng: &mut R) {
for _ in 0..10000 {
let mut a = F::rand(rng);
let mut b = a;
a.add_assign(&b);
b.double();
assert_eq!(a, b);
}
}
fn random_squaring_tests<F: Field, R: Rng>(rng: &mut R) {
for _ in 0..10000 {
let mut a = F::rand(rng);
let mut b = a;
a.mul_assign(&b);
b.square();
assert_eq!(a, b);
}
}
fn random_inversion_tests<F: Field, R: Rng>(rng: &mut R) {
assert!(F::zero().inverse().is_none());
for _ in 0..10000 {
let mut a = F::rand(rng);
let b = a.inverse().unwrap(); // probablistically nonzero
a.mul_assign(&b);
assert_eq!(a, F::one());
}
}
fn random_expansion_tests<F: Field, R: Rng>(rng: &mut R) {
for _ in 0..10000 {
// Compare (a + b)(c + d) and (a*c + b*c + a*d + b*d)
let a = F::rand(rng);
let b = F::rand(rng);
let c = F::rand(rng);
let d = F::rand(rng);
let mut t0 = a;
t0.add_assign(&b);
let mut t1 = c;
t1.add_assign(&d);
t0.mul_assign(&t1);
let mut t2 = a;
t2.mul_assign(&c);
let mut t3 = b;
t3.mul_assign(&c);
let mut t4 = a;
t4.mul_assign(&d);
let mut t5 = b;
t5.mul_assign(&d);
t2.add_assign(&t3);
t2.add_assign(&t4);
t2.add_assign(&t5);
assert_eq!(t0, t2);
}
}

4
pairing/src/tests/mod.rs Normal file
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pub mod curve;
pub mod engine;
pub mod field;
pub mod repr;

98
pairing/src/tests/repr.rs Normal file
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use rand::{SeedableRng, XorShiftRng};
use PrimeFieldRepr;
pub fn random_repr_tests<R: PrimeFieldRepr>() {
random_encoding_tests::<R>();
random_shl_tests::<R>();
random_shr_tests::<R>();
}
fn random_encoding_tests<R: PrimeFieldRepr>() {
let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
for _ in 0..1000 {
let r = R::rand(&mut rng);
// Big endian
{
let mut rdecoded = R::default();
let mut v: Vec<u8> = vec![];
r.write_be(&mut v).unwrap();
rdecoded.read_be(&v[0..]).unwrap();
assert_eq!(r, rdecoded);
}
// Little endian
{
let mut rdecoded = R::default();
let mut v: Vec<u8> = vec![];
r.write_le(&mut v).unwrap();
rdecoded.read_le(&v[0..]).unwrap();
assert_eq!(r, rdecoded);
}
{
let mut rdecoded_le = R::default();
let mut rdecoded_be_flip = R::default();
let mut v: Vec<u8> = vec![];
r.write_le(&mut v).unwrap();
// This reads in little-endian, so we are done.
rdecoded_le.read_le(&v[..]).unwrap();
// This reads in big-endian, so we perform a swap of the
// bytes beforehand.
let v: Vec<u8> = v.into_iter().rev().collect();
rdecoded_be_flip.read_be(&v[..]).unwrap();
assert_eq!(rdecoded_le, rdecoded_be_flip);
}
}
}
fn random_shl_tests<R: PrimeFieldRepr>() {
let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
for _ in 0..100 {
let r = R::rand(&mut rng);
for shift in 0..(r.num_bits() + 1) {
let mut r1 = r;
let mut r2 = r;
for _ in 0..shift {
r1.mul2();
}
r2.shl(shift);
assert_eq!(r1, r2);
}
}
}
fn random_shr_tests<R: PrimeFieldRepr>() {
let mut rng = XorShiftRng::from_seed([0x5dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
for _ in 0..100 {
let r = R::rand(&mut rng);
for shift in 0..(r.num_bits() + 1) {
let mut r1 = r;
let mut r2 = r;
for _ in 0..shift {
r1.div2();
}
r2.shr(shift);
assert_eq!(r1, r2);
}
}
}

179
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use super::{CurveProjective, PrimeField, PrimeFieldRepr};
/// Replaces the contents of `table` with a w-NAF window table for the given window size.
pub(crate) fn wnaf_table<G: CurveProjective>(table: &mut Vec<G>, mut base: G, window: usize) {
table.truncate(0);
table.reserve(1 << (window - 1));
let mut dbl = base;
dbl.double();
for _ in 0..(1 << (window - 1)) {
table.push(base);
base.add_assign(&dbl);
}
}
/// Replaces the contents of `wnaf` with the w-NAF representation of a scalar.
pub(crate) fn wnaf_form<S: PrimeFieldRepr>(wnaf: &mut Vec<i64>, mut c: S, window: usize) {
wnaf.truncate(0);
while !c.is_zero() {
let mut u;
if c.is_odd() {
u = (c.as_ref()[0] % (1 << (window + 1))) as i64;
if u > (1 << window) {
u -= 1 << (window + 1);
}
if u > 0 {
c.sub_noborrow(&S::from(u as u64));
} else {
c.add_nocarry(&S::from((-u) as u64));
}
} else {
u = 0;
}
wnaf.push(u);
c.div2();
}
}
/// Performs w-NAF exponentiation with the provided window table and w-NAF form scalar.
///
/// This function must be provided a `table` and `wnaf` that were constructed with
/// the same window size; otherwise, it may panic or produce invalid results.
pub(crate) fn wnaf_exp<G: CurveProjective>(table: &[G], wnaf: &[i64]) -> G {
let mut result = G::zero();
let mut found_one = false;
for n in wnaf.iter().rev() {
if found_one {
result.double();
}
if *n != 0 {
found_one = true;
if *n > 0 {
result.add_assign(&table[(n / 2) as usize]);
} else {
result.sub_assign(&table[((-n) / 2) as usize]);
}
}
}
result
}
/// A "w-ary non-adjacent form" exponentiation context.
#[derive(Debug)]
pub struct Wnaf<W, B, S> {
base: B,
scalar: S,
window_size: W,
}
impl<G: CurveProjective> Wnaf<(), Vec<G>, Vec<i64>> {
/// Construct a new wNAF context without allocating.
pub fn new() -> Self {
Wnaf {
base: vec![],
scalar: vec![],
window_size: (),
}
}
/// Given a base and a number of scalars, compute a window table and return a `Wnaf` object that
/// can perform exponentiations with `.scalar(..)`.
pub fn base(&mut self, base: G, num_scalars: usize) -> Wnaf<usize, &[G], &mut Vec<i64>> {
// Compute the appropriate window size based on the number of scalars.
let window_size = G::recommended_wnaf_for_num_scalars(num_scalars);
// Compute a wNAF table for the provided base and window size.
wnaf_table(&mut self.base, base, window_size);
// Return a Wnaf object that immutably borrows the computed base storage location,
// but mutably borrows the scalar storage location.
Wnaf {
base: &self.base[..],
scalar: &mut self.scalar,
window_size,
}
}
/// Given a scalar, compute its wNAF representation and return a `Wnaf` object that can perform
/// exponentiations with `.base(..)`.
pub fn scalar(
&mut self,
scalar: <<G as CurveProjective>::Scalar as PrimeField>::Repr,
) -> Wnaf<usize, &mut Vec<G>, &[i64]> {
// Compute the appropriate window size for the scalar.
let window_size = G::recommended_wnaf_for_scalar(scalar);
// Compute the wNAF form of the scalar.
wnaf_form(&mut self.scalar, scalar, window_size);
// Return a Wnaf object that mutably borrows the base storage location, but
// immutably borrows the computed wNAF form scalar location.
Wnaf {
base: &mut self.base,
scalar: &self.scalar[..],
window_size,
}
}
}
impl<'a, G: CurveProjective> Wnaf<usize, &'a [G], &'a mut Vec<i64>> {
/// Constructs new space for the scalar representation while borrowing
/// the computed window table, for sending the window table across threads.
pub fn shared(&self) -> Wnaf<usize, &'a [G], Vec<i64>> {
Wnaf {
base: self.base,
scalar: vec![],
window_size: self.window_size,
}
}
}
impl<'a, G: CurveProjective> Wnaf<usize, &'a mut Vec<G>, &'a [i64]> {
/// Constructs new space for the window table while borrowing
/// the computed scalar representation, for sending the scalar representation
/// across threads.
pub fn shared(&self) -> Wnaf<usize, Vec<G>, &'a [i64]> {
Wnaf {
base: vec![],
scalar: self.scalar,
window_size: self.window_size,
}
}
}
impl<B, S: AsRef<[i64]>> Wnaf<usize, B, S> {
/// Performs exponentiation given a base.
pub fn base<G: CurveProjective>(&mut self, base: G) -> G
where
B: AsMut<Vec<G>>,
{
wnaf_table(self.base.as_mut(), base, self.window_size);
wnaf_exp(self.base.as_mut(), self.scalar.as_ref())
}
}
impl<B, S: AsMut<Vec<i64>>> Wnaf<usize, B, S> {
/// Performs exponentiation given a scalar.
pub fn scalar<G: CurveProjective>(
&mut self,
scalar: <<G as CurveProjective>::Scalar as PrimeField>::Repr,
) -> G
where
B: AsRef<[G]>,
{
wnaf_form(self.scalar.as_mut(), scalar, self.window_size);
wnaf_exp(self.base.as_ref(), self.scalar.as_mut())
}
}