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Merge pull request #53 from ebfull/circuit-improvements

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Minor circuit improvements
This commit is contained in:
ebfull
2018-03-15 12:47:26 -06:00
committed by GitHub
parent 3c07a2d9b3 21625d69e0
commit 39f1152e16
8 changed files with 1067 additions and 786 deletions
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15
src/circuit/blake2s.rs
View File

@@ -15,6 +15,8 @@ use super::uint32::{
UInt32 UInt32
}; };
use super::multieq::MultiEq;
/* /*
2.1. Parameters 2.1. Parameters
The following table summarizes various parameters and their ranges: The following table summarizes various parameters and their ranges:
@@ -88,8 +90,8 @@ const SIGMA: [[usize; 16]; 10] = [
END FUNCTION. END FUNCTION.
*/ */
fn mixing_g<E: Engine, CS: ConstraintSystem<E>>( fn mixing_g<E: Engine, CS: ConstraintSystem<E>, M>(
mut cs: CS, mut cs: M,
v: &mut [UInt32], v: &mut [UInt32],
a: usize, a: usize,
b: usize, b: usize,
@@ -98,6 +100,7 @@ fn mixing_g<E: Engine, CS: ConstraintSystem<E>>(
x: &UInt32, x: &UInt32,
y: &UInt32 y: &UInt32
) -> Result<(), SynthesisError> ) -> Result<(), SynthesisError>
where M: ConstraintSystem<E, Root=MultiEq<E, CS>>
{ {
v[a] = UInt32::addmany(cs.namespace(|| "mixing step 1"), &[v[a].clone(), v[b].clone(), x.clone()])?; v[a] = UInt32::addmany(cs.namespace(|| "mixing step 1"), &[v[a].clone(), v[b].clone(), x.clone()])?;
v[d] = v[d].xor(cs.namespace(|| "mixing step 2"), &v[a])?.rotr(R1); v[d] = v[d].xor(cs.namespace(|| "mixing step 2"), &v[a])?.rotr(R1);
@@ -199,6 +202,9 @@ fn blake2s_compression<E: Engine, CS: ConstraintSystem<E>>(
v[14] = v[14].xor(cs.namespace(|| "third xor"), &UInt32::constant(u32::max_value()))?; v[14] = v[14].xor(cs.namespace(|| "third xor"), &UInt32::constant(u32::max_value()))?;
} }
{
let mut cs = MultiEq::new(&mut cs);
for i in 0..10 { for i in 0..10 {
let mut cs = cs.namespace(|| format!("round {}", i)); let mut cs = cs.namespace(|| format!("round {}", i));
@@ -214,6 +220,7 @@ fn blake2s_compression<E: Engine, CS: ConstraintSystem<E>>(
mixing_g(cs.namespace(|| "mixing invocation 7"), &mut v, 2, 7, 8, 13, &m[s[12]], &m[s[13]])?; mixing_g(cs.namespace(|| "mixing invocation 7"), &mut v, 2, 7, 8, 13, &m[s[12]], &m[s[13]])?;
mixing_g(cs.namespace(|| "mixing invocation 8"), &mut v, 3, 4, 9, 14, &m[s[14]], &m[s[15]])?; mixing_g(cs.namespace(|| "mixing invocation 8"), &mut v, 3, 4, 9, 14, &m[s[14]], &m[s[15]])?;
} }
}
for i in 0..8 { for i in 0..8 {
let mut cs = cs.namespace(|| format!("h[{i}] ^ v[{i}] ^ v[{i} + 8]", i=i)); let mut cs = cs.namespace(|| format!("h[{i}] ^ v[{i}] ^ v[{i} + 8]", i=i));
@@ -350,7 +357,7 @@ mod test {
let input_bits: Vec<_> = (0..512).map(|i| AllocatedBit::alloc(cs.namespace(|| format!("input bit {}", i)), Some(true)).unwrap().into()).collect(); let input_bits: Vec<_> = (0..512).map(|i| AllocatedBit::alloc(cs.namespace(|| format!("input bit {}", i)), Some(true)).unwrap().into()).collect();
blake2s(&mut cs, &input_bits, b"12345678").unwrap(); blake2s(&mut cs, &input_bits, b"12345678").unwrap();
assert!(cs.is_satisfied()); assert!(cs.is_satisfied());
assert_eq!(cs.num_constraints(), 21792); assert_eq!(cs.num_constraints(), 21518);
} }
#[test] #[test]
@@ -367,7 +374,7 @@ mod test {
.collect(); .collect();
blake2s(&mut cs, &input_bits, b"12345678").unwrap(); blake2s(&mut cs, &input_bits, b"12345678").unwrap();
assert!(cs.is_satisfied()); assert!(cs.is_satisfied());
assert_eq!(cs.num_constraints(), 21792); assert_eq!(cs.num_constraints(), 21518);
} }
#[test] #[test]

7
src/circuit/boolean.rs
View File

@@ -367,6 +367,13 @@ pub enum Boolean {
} }
impl Boolean { impl Boolean {
pub fn is_constant(&self) -> bool {
match *self {
Boolean::Constant(_) => true,
_ => false
}
}
pub fn enforce_equal<E, CS>( pub fn enforce_equal<E, CS>(
mut cs: CS, mut cs: CS,
a: &Self, a: &Self,

742
src/circuit/mod.rs
View File

@@ -2,35 +2,19 @@
pub mod test; pub mod test;
pub mod boolean; pub mod boolean;
pub mod multieq;
pub mod uint32; pub mod uint32;
pub mod blake2s; pub mod blake2s;
pub mod num; pub mod num;
pub mod lookup; pub mod lookup;
pub mod ecc; pub mod ecc;
pub mod pedersen_hash; pub mod pedersen_hash;
pub mod multipack;
use pairing::{ pub mod sapling;
PrimeField,
PrimeFieldRepr,
};
use bellman::{ use bellman::{
SynthesisError, SynthesisError
ConstraintSystem,
Circuit
};
use jubjub::{
JubjubEngine,
FixedGenerators
};
use constants;
use primitives::{
ValueCommitment,
ProofGenerationKey,
PaymentAddress
}; };
// TODO: This should probably be removed and we // TODO: This should probably be removed and we
@@ -51,721 +35,3 @@ impl<T> Assignment<T> for Option<T> {
} }
} }
} }
/// This is an instance of the `Spend` circuit.
pub struct Spend<'a, E: JubjubEngine> {
pub params: &'a E::Params,
/// Pedersen commitment to the value being spent
pub value_commitment: Option<ValueCommitment<E>>,
/// Key required to construct proofs for spending notes
/// for a particular spending key
pub proof_generation_key: Option<ProofGenerationKey<E>>,
/// The payment address associated with the note
pub payment_address: Option<PaymentAddress<E>>,
/// The randomness of the note commitment
pub commitment_randomness: Option<E::Fs>,
/// The authentication path of the commitment in the tree
pub auth_path: Vec<Option<(E::Fr, bool)>>
}
/// This is an output circuit instance.
pub struct Output<'a, E: JubjubEngine> {
pub params: &'a E::Params,
/// Pedersen commitment to the value being spent
pub value_commitment: Option<ValueCommitment<E>>,
/// The payment address of the recipient
pub payment_address: Option<PaymentAddress<E>>,
/// The randomness used to hide the note commitment data
pub commitment_randomness: Option<E::Fs>,
/// The ephemeral secret key for DH with recipient
pub esk: Option<E::Fs>
}
/// Exposes a Pedersen commitment to the value as an
/// input to the circuit
fn expose_value_commitment<E, CS>(
mut cs: CS,
value_commitment: Option<ValueCommitment<E>>,
params: &E::Params
) -> Result<Vec<boolean::Boolean>, SynthesisError>
where E: JubjubEngine,
CS: ConstraintSystem<E>
{
// Booleanize the value into little-endian bit order
let value_bits = boolean::u64_into_boolean_vec_le(
cs.namespace(|| "value"),
value_commitment.as_ref().map(|c| c.value)
)?;
// Compute the note value in the exponent
let gv = ecc::fixed_base_multiplication(
cs.namespace(|| "compute the value in the exponent"),
FixedGenerators::ValueCommitmentValue,
&value_bits,
params
)?;
// Booleanize the randomness. This does not ensure
// the bit representation is "in the field" because
// it doesn't matter for security.
let hr = boolean::field_into_boolean_vec_le(
cs.namespace(|| "hr"),
value_commitment.as_ref().map(|c| c.randomness)
)?;
// Compute the randomness in the exponent
let hr = ecc::fixed_base_multiplication(
cs.namespace(|| "computation of randomization for value commitment"),
FixedGenerators::ValueCommitmentRandomness,
&hr,
params
)?;
// Compute the Pedersen commitment to the value
let gvhr = gv.add(
cs.namespace(|| "computation of value commitment"),
&hr,
params
)?;
// Expose the commitment as an input to the circuit
gvhr.inputize(cs.namespace(|| "commitment point"))?;
Ok(value_bits)
}
impl<'a, E: JubjubEngine> Circuit<E> for Spend<'a, E> {
fn synthesize<CS: ConstraintSystem<E>>(self, cs: &mut CS) -> Result<(), SynthesisError>
{
let value_bits = expose_value_commitment(
cs.namespace(|| "value commitment"),
self.value_commitment,
self.params
)?;
// Compute rk = [rsk] ProvingPublicKey
let rk;
{
// Witness rsk as bits
let rsk = boolean::field_into_boolean_vec_le(
cs.namespace(|| "rsk"),
self.proof_generation_key.as_ref().map(|k| k.rsk.clone())
)?;
// NB: We don't ensure that the bit representation of rsk
// is "in the field" (Fs) because it's not used except to
// demonstrate the prover knows it. If they know a
// congruency then that's equivalent.
// Compute rk = [rsk] ProvingPublicKey
rk = ecc::fixed_base_multiplication(
cs.namespace(|| "computation of rk"),
FixedGenerators::ProofGenerationKey,
&rsk,
self.params
)?;
}
// Prover witnesses ak (ensures that it's on the curve)
let ak = ecc::EdwardsPoint::witness(
cs.namespace(|| "ak"),
self.proof_generation_key.as_ref().map(|k| k.ak.clone()),
self.params
)?;
// There are no sensible attacks on small order points
// of ak (that we're aware of!) but it's a cheap check,
// so we do it.
ak.assert_not_small_order(
cs.namespace(|| "ak not small order"),
self.params
)?;
// Unpack ak and rk for input to BLAKE2s
// This is the "viewing key" preimage for CRH^ivk
let mut vk = vec![];
vk.extend(
ak.repr(cs.namespace(|| "representation of ak"))?
);
// This is the nullifier randomness preimage for PRF^nr
let mut nr_preimage = vec![];
// Extend vk and nr preimages with the representation of
// rk.
{
let repr_rk = rk.repr(
cs.namespace(|| "representation of rk")
)?;
vk.extend(repr_rk.iter().cloned());
nr_preimage.extend(repr_rk);
}
assert_eq!(vk.len(), 512);
assert_eq!(nr_preimage.len(), 256);
// Compute the incoming viewing key ivk
let mut ivk = blake2s::blake2s(
cs.namespace(|| "computation of ivk"),
&vk,
constants::CRH_IVK_PERSONALIZATION
)?;
// Little endian bit order
ivk.reverse();
// drop_5 to ensure it's in the field
ivk.truncate(E::Fs::CAPACITY as usize);
// Witness g_d. Ensures the point is on the
// curve, but not its order. If the prover
// manages to witness a commitment in the
// tree, then the Output circuit would have
// already guaranteed this.
let g_d = {
// This binding is to avoid a weird edge case in Rust's
// ownership/borrowing rules. self is partially moved
// above, but the closure for and_then will have to
// move self (or a reference to self) to reference
// self.params, so we have to copy self.params here.
let params = self.params;
ecc::EdwardsPoint::witness(
cs.namespace(|| "witness g_d"),
self.payment_address.as_ref().and_then(|a| a.g_d(params)),
self.params
)?
};
// Check that g_d is not small order. Technically, this check
// is already done in the Output circuit, and this proof ensures
// g_d is bound to a product of that check, but for defense in
// depth let's check it anyway. It's cheap.
g_d.assert_not_small_order(cs.namespace(|| "g_d not small order"), self.params)?;
// Compute pk_d = g_d^ivk
let pk_d = g_d.mul(
cs.namespace(|| "compute pk_d"),
&ivk,
self.params
)?;
// Compute note contents
// value (in big endian) followed by g_d and pk_d
let mut note_contents = vec![];
note_contents.extend(value_bits.into_iter().rev());
note_contents.extend(
g_d.repr(cs.namespace(|| "representation of g_d"))?
);
note_contents.extend(
pk_d.repr(cs.namespace(|| "representation of pk_d"))?
);
assert_eq!(
note_contents.len(),
64 + // value
256 + // g_d
256 // p_d
);
// Compute the hash of the note contents
let mut cm = pedersen_hash::pedersen_hash(
cs.namespace(|| "note content hash"),
pedersen_hash::Personalization::NoteCommitment,
&note_contents,
self.params
)?;
{
// Booleanize the randomness for the note commitment
let cmr = boolean::field_into_boolean_vec_le(
cs.namespace(|| "cmr"),
self.commitment_randomness
)?;
// Compute the note commitment randomness in the exponent
let cmr = ecc::fixed_base_multiplication(
cs.namespace(|| "computation of commitment randomness"),
FixedGenerators::NoteCommitmentRandomness,
&cmr,
self.params
)?;
// Randomize the note commitment. Pedersen hashes are not
// themselves hiding commitments.
cm = cm.add(
cs.namespace(|| "randomization of note commitment"),
&cmr,
self.params
)?;
}
let tree_depth = self.auth_path.len();
// This will store (least significant bit first)
// the position of the note in the tree, for use
// in nullifier computation.
let mut position_bits = vec![];
// This is an injective encoding, as cur is a
// point in the prime order subgroup.
let mut cur = cm.get_x().clone();
for (i, e) in self.auth_path.into_iter().enumerate() {
let cs = &mut cs.namespace(|| format!("merkle tree hash {}", i));
// Determines if the current subtree is the "right" leaf at this
// depth of the tree.
let cur_is_right = boolean::Boolean::from(boolean::AllocatedBit::alloc(
cs.namespace(|| "position bit"),
e.map(|e| e.1)
)?);
// Push this boolean for nullifier computation later
position_bits.push(cur_is_right.clone());
// Witness the authentication path element adjacent
// at this depth.
let path_element = num::AllocatedNum::alloc(
cs.namespace(|| "path element"),
|| {
Ok(e.get()?.0)
}
)?;
// Swap the two if the current subtree is on the right
let (xl, xr) = num::AllocatedNum::conditionally_reverse(
cs.namespace(|| "conditional reversal of preimage"),
&cur,
&path_element,
&cur_is_right
)?;
// We don't need to be strict, because the function is
// collision-resistant. If the prover witnesses a congruency,
// they will be unable to find an authentication path in the
// tree with high probability.
let mut preimage = vec![];
preimage.extend(xl.into_bits_le(cs.namespace(|| "xl into bits"))?);
preimage.extend(xr.into_bits_le(cs.namespace(|| "xr into bits"))?);
// Compute the new subtree value
cur = pedersen_hash::pedersen_hash(
cs.namespace(|| "computation of pedersen hash"),
pedersen_hash::Personalization::MerkleTree(i),
&preimage,
self.params
)?.get_x().clone(); // Injective encoding
}
assert_eq!(position_bits.len(), tree_depth);
// Expose the anchor
cur.inputize(cs.namespace(|| "anchor"))?;
// Compute the cm + g^position for preventing
// faerie gold attacks
{
// Compute the position in the exponent
let position = ecc::fixed_base_multiplication(
cs.namespace(|| "g^position"),
FixedGenerators::NullifierPosition,
&position_bits,
self.params
)?;
// Add the position to the commitment
cm = cm.add(
cs.namespace(|| "faerie gold prevention"),
&position,
self.params
)?;
}
// Let's compute nr = BLAKE2s(rk || cm + position)
nr_preimage.extend(
cm.repr(cs.namespace(|| "representation of cm"))?
);
assert_eq!(nr_preimage.len(), 512);
// Compute nr
let mut nr = blake2s::blake2s(
cs.namespace(|| "nr computation"),
&nr_preimage,
constants::PRF_NR_PERSONALIZATION
)?;
// Little endian bit order
nr.reverse();
// We want the randomization in the field to
// simplify outside code.
// TODO: This isn't uniformly random.
nr.truncate(E::Fs::CAPACITY as usize);
// Compute nullifier
let nf = ak.mul(
cs.namespace(|| "computation of nf"),
&nr,
self.params
)?;
// Expose the nullifier publicly
nf.inputize(cs.namespace(|| "nullifier"))?;
Ok(())
}
}
impl<'a, E: JubjubEngine> Circuit<E> for Output<'a, E> {
fn synthesize<CS: ConstraintSystem<E>>(self, cs: &mut CS) -> Result<(), SynthesisError>
{
let value_bits = expose_value_commitment(
cs.namespace(|| "value commitment"),
self.value_commitment,
self.params
)?;
// Let's start to construct our note, which contains
// value (big endian)
let mut note_contents = vec![];
note_contents.extend(value_bits.into_iter().rev());
// Let's deal with g_d
{
let params = self.params;
// Prover witnesses g_d, ensuring it's on the
// curve.
let g_d = ecc::EdwardsPoint::witness(
cs.namespace(|| "witness g_d"),
self.payment_address.as_ref().and_then(|a| a.g_d(params)),
self.params
)?;
// g_d is ensured to be large order. The relationship
// between g_d and pk_d ultimately binds ivk to the
// note. If this were a small order point, it would
// not do this correctly, and the prover could
// double-spend by finding random ivk's that satisfy
// the relationship.
//
// Further, if it were small order, epk would be
// small order too!
g_d.assert_not_small_order(
cs.namespace(|| "g_d not small order"),
self.params
)?;
// Extend our note contents with the representation of
// g_d.
note_contents.extend(
g_d.repr(cs.namespace(|| "representation of g_d"))?
);
// Booleanize our ephemeral secret key
let esk = boolean::field_into_boolean_vec_le(
cs.namespace(|| "esk"),
self.esk
)?;
// Create the ephemeral public key from g_d.
let epk = g_d.mul(
cs.namespace(|| "epk computation"),
&esk,
self.params
)?;
// Expose epk publicly.
epk.inputize(cs.namespace(|| "epk"))?;
}
// Now let's deal with pk_d. We don't do any checks and
// essentially allow the prover to witness any 256 bits
// they would like.
{
// Just grab pk_d from the witness
let pk_d = self.payment_address.as_ref().map(|e| e.pk_d.into_xy());
// Witness the y-coordinate, encoded as little
// endian bits (to match the representation)
let y_contents = boolean::field_into_boolean_vec_le(
cs.namespace(|| "pk_d bits of y"),
pk_d.map(|e| e.1)
)?;
// Witness the sign bit
let sign_bit = boolean::Boolean::from(boolean::AllocatedBit::alloc(
cs.namespace(|| "pk_d bit of x"),
pk_d.map(|e| e.0.into_repr().is_odd())
)?);
// Extend the note with pk_d representation
note_contents.extend(y_contents);
note_contents.push(sign_bit);
}
assert_eq!(
note_contents.len(),
64 + // value
256 + // g_d
256 // p_d
);
// Compute the hash of the note contents
let mut cm = pedersen_hash::pedersen_hash(
cs.namespace(|| "note content hash"),
pedersen_hash::Personalization::NoteCommitment,
&note_contents,
self.params
)?;
{
// Booleanize the randomness
let cmr = boolean::field_into_boolean_vec_le(
cs.namespace(|| "cmr"),
self.commitment_randomness
)?;
// Compute the note commitment randomness in the exponent
let cmr = ecc::fixed_base_multiplication(
cs.namespace(|| "computation of commitment randomness"),
FixedGenerators::NoteCommitmentRandomness,
&cmr,
self.params
)?;
// Randomize our note commitment
cm = cm.add(
cs.namespace(|| "randomization of note commitment"),
&cmr,
self.params
)?;
}
// Only the x-coordinate of the output is revealed,
// since we know it is prime order, and we know that
// the x-coordinate is an injective encoding for
// prime-order elements.
cm.get_x().inputize(cs.namespace(|| "commitment"))?;
Ok(())
}
}
#[test]
fn test_input_circuit_with_bls12_381() {
use pairing::{Field, BitIterator};
use pairing::bls12_381::*;
use rand::{SeedableRng, Rng, XorShiftRng};
use ::circuit::test::*;
use jubjub::{JubjubBls12, fs, edwards};
let params = &JubjubBls12::new();
let rng = &mut XorShiftRng::from_seed([0x3dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
let tree_depth = 32;
let value_commitment = ValueCommitment {
value: rng.gen(),
randomness: rng.gen()
};
let rsk: fs::Fs = rng.gen();
let ak = edwards::Point::rand(rng, params).mul_by_cofactor(params);
let proof_generation_key = ::primitives::ProofGenerationKey {
ak: ak.clone(),
rsk: rsk.clone()
};
let viewing_key = proof_generation_key.into_viewing_key(params);
let payment_address;
loop {
let diversifier = ::primitives::Diversifier(rng.gen());
if let Some(p) = viewing_key.into_payment_address(
diversifier,
params
)
{
payment_address = p;
break;
}
}
let g_d = payment_address.diversifier.g_d(params).unwrap();
let commitment_randomness: fs::Fs = rng.gen();
let auth_path = vec![Some((rng.gen(), rng.gen())); tree_depth];
{
let mut cs = TestConstraintSystem::<Bls12>::new();
let instance = Spend {
params: params,
value_commitment: Some(value_commitment.clone()),
proof_generation_key: Some(proof_generation_key.clone()),
payment_address: Some(payment_address.clone()),
commitment_randomness: Some(commitment_randomness),
auth_path: auth_path.clone()
};
instance.synthesize(&mut cs).unwrap();
assert!(cs.is_satisfied());
assert_eq!(cs.num_constraints(), 101566);
assert_eq!(cs.hash(), "e3d226975c99e17ef30f5a4b7e87d355ef3dbd80eed0c8de43780f3028946d82");
let expected_value_cm = value_commitment.cm(params).into_xy();
assert_eq!(cs.num_inputs(), 6);
assert_eq!(cs.get_input(0, "ONE"), Fr::one());
assert_eq!(cs.get_input(1, "value commitment/commitment point/x/input variable"), expected_value_cm.0);
assert_eq!(cs.get_input(2, "value commitment/commitment point/y/input variable"), expected_value_cm.1);
let note = ::primitives::Note {
value: value_commitment.value,
g_d: g_d.clone(),
pk_d: payment_address.pk_d.clone(),
r: commitment_randomness.clone()
};
let mut position = 0u64;
let mut cur = note.cm(params);
assert_eq!(cs.get("randomization of note commitment/x3/num"), cur);
for (i, val) in auth_path.into_iter().enumerate()
{
let (uncle, b) = val.unwrap();
let mut lhs = cur;
let mut rhs = uncle;
if b {
::std::mem::swap(&mut lhs, &mut rhs);
}
let mut lhs: Vec<bool> = BitIterator::new(lhs.into_repr()).collect();
let mut rhs: Vec<bool> = BitIterator::new(rhs.into_repr()).collect();
lhs.reverse();
rhs.reverse();
cur = ::pedersen_hash::pedersen_hash::<Bls12, _>(
::pedersen_hash::Personalization::MerkleTree(i),
lhs.into_iter()
.take(Fr::NUM_BITS as usize)
.chain(rhs.into_iter().take(Fr::NUM_BITS as usize)),
params
).into_xy().0;
if b {
position |= 1 << i;
}
}
let expected_nf = note.nf(&viewing_key, position, params);
let expected_nf_xy = expected_nf.into_xy();
assert_eq!(cs.get_input(3, "anchor/input variable"), cur);
assert_eq!(cs.get_input(4, "nullifier/x/input variable"), expected_nf_xy.0);
assert_eq!(cs.get_input(5, "nullifier/y/input variable"), expected_nf_xy.1);
}
}
#[test]
fn test_output_circuit_with_bls12_381() {
use pairing::{Field};
use pairing::bls12_381::*;
use rand::{SeedableRng, Rng, XorShiftRng};
use ::circuit::test::*;
use jubjub::{JubjubBls12, fs, edwards};
let params = &JubjubBls12::new();
let rng = &mut XorShiftRng::from_seed([0x3dbe6258, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
let value_commitment = ValueCommitment {
value: rng.gen(),
randomness: rng.gen()
};
let rsk: fs::Fs = rng.gen();
let ak = edwards::Point::rand(rng, params).mul_by_cofactor(params);
let proof_generation_key = ::primitives::ProofGenerationKey {
ak: ak.clone(),
rsk: rsk.clone()
};
let viewing_key = proof_generation_key.into_viewing_key(params);
let payment_address;
loop {
let diversifier = ::primitives::Diversifier(rng.gen());
if let Some(p) = viewing_key.into_payment_address(
diversifier,
params
)
{
payment_address = p;
break;
}
}
let commitment_randomness: fs::Fs = rng.gen();
let esk: fs::Fs = rng.gen();
{
let mut cs = TestConstraintSystem::<Bls12>::new();
let instance = Output {
params: params,
value_commitment: Some(value_commitment.clone()),
payment_address: Some(payment_address.clone()),
commitment_randomness: Some(commitment_randomness),
esk: Some(esk.clone())
};
instance.synthesize(&mut cs).unwrap();
assert!(cs.is_satisfied());
assert_eq!(cs.num_constraints(), 7827);
assert_eq!(cs.hash(), "2896f259ad7a50c83604976ee9362358396d547b70f2feaf91d82d287e4ffc1d");
let expected_cm = payment_address.create_note(
value_commitment.value,
commitment_randomness,
params
).expect("should be valid").cm(params);
let expected_value_cm = value_commitment.cm(params).into_xy();
let expected_epk = payment_address.g_d(params).expect("should be valid").mul(esk, params);
let expected_epk_xy = expected_epk.into_xy();
assert_eq!(cs.num_inputs(), 6);
assert_eq!(cs.get_input(0, "ONE"), Fr::one());
assert_eq!(cs.get_input(1, "value commitment/commitment point/x/input variable"), expected_value_cm.0);
assert_eq!(cs.get_input(2, "value commitment/commitment point/y/input variable"), expected_value_cm.1);
assert_eq!(cs.get_input(3, "epk/x/input variable"), expected_epk_xy.0);
assert_eq!(cs.get_input(4, "epk/y/input variable"), expected_epk_xy.1);
assert_eq!(cs.get_input(5, "commitment/input variable"), expected_cm);
}
}

137
src/circuit/multieq.rs Normal file
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use pairing::{
Engine,
Field,
PrimeField
};
use bellman::{
SynthesisError,
ConstraintSystem,
LinearCombination,
Variable
};
pub struct MultiEq<E: Engine, CS: ConstraintSystem<E>>{
cs: CS,
ops: usize,
bits_used: usize,
lhs: LinearCombination<E>,
rhs: LinearCombination<E>,
}
impl<E: Engine, CS: ConstraintSystem<E>> MultiEq<E, CS> {
pub fn new(cs: CS) -> Self {
MultiEq {
cs: cs,
ops: 0,
bits_used: 0,
lhs: LinearCombination::zero(),
rhs: LinearCombination::zero()
}
}
fn accumulate(&mut self)
{
let ops = self.ops;
let lhs = self.lhs.clone();
let rhs = self.rhs.clone();
self.cs.enforce(
|| format!("multieq {}", ops),
|_| lhs,
|lc| lc + CS::one(),
|_| rhs
);
self.lhs = LinearCombination::zero();
self.rhs = LinearCombination::zero();
self.bits_used = 0;
self.ops += 1;
}
pub fn enforce_equal(
&mut self,
num_bits: usize,
lhs: &LinearCombination<E>,
rhs: &LinearCombination<E>
)
{
// Check if we will exceed the capacity
if (E::Fr::CAPACITY as usize) <= (self.bits_used + num_bits) {
self.accumulate();
}
assert!((E::Fr::CAPACITY as usize) > (self.bits_used + num_bits));
let coeff = E::Fr::from_str("2").unwrap().pow(&[self.bits_used as u64]);
self.lhs = self.lhs.clone() + (coeff, lhs);
self.rhs = self.rhs.clone() + (coeff, rhs);
self.bits_used += num_bits;
}
}
impl<E: Engine, CS: ConstraintSystem<E>> Drop for MultiEq<E, CS> {
fn drop(&mut self) {
if self.bits_used > 0 {
self.accumulate();
}
}
}
impl<E: Engine, CS: ConstraintSystem<E>> ConstraintSystem<E> for MultiEq<E, CS>
{
type Root = Self;
fn one() -> Variable {
CS::one()
}
fn alloc<F, A, AR>(
&mut self,
annotation: A,
f: F
) -> Result<Variable, SynthesisError>
where F: FnOnce() -> Result<E::Fr, SynthesisError>, A: FnOnce() -> AR, AR: Into<String>
{
self.cs.alloc(annotation, f)
}
fn alloc_input<F, A, AR>(
&mut self,
annotation: A,
f: F
) -> Result<Variable, SynthesisError>
where F: FnOnce() -> Result<E::Fr, SynthesisError>, A: FnOnce() -> AR, AR: Into<String>
{
self.cs.alloc_input(annotation, f)
}
fn enforce<A, AR, LA, LB, LC>(
&mut self,
annotation: A,
a: LA,
b: LB,
c: LC
)
where A: FnOnce() -> AR, AR: Into<String>,
LA: FnOnce(LinearCombination<E>) -> LinearCombination<E>,
LB: FnOnce(LinearCombination<E>) -> LinearCombination<E>,
LC: FnOnce(LinearCombination<E>) -> LinearCombination<E>
{
self.cs.enforce(annotation, a, b, c)
}
fn push_namespace<NR, N>(&mut self, name_fn: N)
where NR: Into<String>, N: FnOnce() -> NR
{
self.cs.get_root().push_namespace(name_fn)
}
fn pop_namespace(&mut self)
{
self.cs.get_root().pop_namespace()
}
fn get_root(&mut self) -> &mut Self::Root
{
self
}
}

106
src/circuit/multipack.rs Normal file
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use pairing::{Engine, Field, PrimeField};
use bellman::{ConstraintSystem, SynthesisError};
use super::boolean::{Boolean};
use super::num::Num;
use super::Assignment;
/// Takes a sequence of booleans and exposes them as compact
/// public inputs
pub fn pack_into_inputs<E, CS>(
mut cs: CS,
bits: &[Boolean]
) -> Result<(), SynthesisError>
where E: Engine, CS: ConstraintSystem<E>
{
for (i, bits) in bits.chunks(E::Fr::CAPACITY as usize).enumerate()
{
let mut num = Num::<E>::zero();
let mut coeff = E::Fr::one();
for bit in bits {
num = num.add_bool_with_coeff(CS::one(), bit, coeff);
coeff.double();
}
let input = cs.alloc_input(|| format!("input {}", i), || {
Ok(*num.get_value().get()?)
})?;
// num * 1 = input
cs.enforce(
|| format!("packing constraint {}", i),
|_| num.lc(E::Fr::one()),
|lc| lc + CS::one(),
|lc| lc + input
);
}
Ok(())
}
pub fn bytes_to_bits(bytes: &[u8]) -> Vec<bool>
{
bytes.iter()
.flat_map(|&v| (0..8).rev().map(move |i| (v >> i) & 1 == 1))
.collect()
}
pub fn compute_multipacking<E: Engine>(
bits: &[bool]
) -> Vec<E::Fr>
{
let mut result = vec![];
for bits in bits.chunks(E::Fr::CAPACITY as usize)
{
let mut cur = E::Fr::zero();
let mut coeff = E::Fr::one();
for bit in bits {
if *bit {
cur.add_assign(&coeff);
}
coeff.double();
}
result.push(cur);
}
result
}
#[test]
fn test_multipacking() {
use rand::{SeedableRng, Rng, XorShiftRng};
use bellman::{ConstraintSystem};
use pairing::bls12_381::{Bls12};
use ::circuit::test::*;
use super::boolean::{AllocatedBit, Boolean};
let mut rng = XorShiftRng::from_seed([0x3dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
for num_bits in 0..1500 {
let mut cs = TestConstraintSystem::<Bls12>::new();
let bits: Vec<bool> = (0..num_bits).map(|_| rng.gen()).collect();
let circuit_bits = bits.iter().enumerate()
.map(|(i, &b)| {
Boolean::from(
AllocatedBit::alloc(
cs.namespace(|| format!("bit {}", i)),
Some(b)
).unwrap()
)
})
.collect::<Vec<_>>();
let expected_inputs = compute_multipacking::<Bls12>(&bits);
pack_into_inputs(cs.namespace(|| "pack"), &circuit_bits).unwrap();
assert!(cs.is_satisfied());
assert!(cs.verify(&expected_inputs));
}
}

748
src/circuit/sapling/mod.rs Normal file
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use pairing::{
PrimeField,
PrimeFieldRepr,
};
use bellman::{
SynthesisError,
ConstraintSystem,
Circuit
};
use jubjub::{
JubjubEngine,
FixedGenerators
};
use constants;
use primitives::{
ValueCommitment,
ProofGenerationKey,
PaymentAddress
};
use super::Assignment;
use super::boolean;
use super::ecc;
use super::pedersen_hash;
use super::blake2s;
use super::num;
/// This is an instance of the `Spend` circuit.
pub struct Spend<'a, E: JubjubEngine> {
pub params: &'a E::Params,
/// Pedersen commitment to the value being spent
pub value_commitment: Option<ValueCommitment<E>>,
/// Key required to construct proofs for spending notes
/// for a particular spending key
pub proof_generation_key: Option<ProofGenerationKey<E>>,
/// The payment address associated with the note
pub payment_address: Option<PaymentAddress<E>>,
/// The randomness of the note commitment
pub commitment_randomness: Option<E::Fs>,
/// The authentication path of the commitment in the tree
pub auth_path: Vec<Option<(E::Fr, bool)>>
}
/// This is an output circuit instance.
pub struct Output<'a, E: JubjubEngine> {
pub params: &'a E::Params,
/// Pedersen commitment to the value being spent
pub value_commitment: Option<ValueCommitment<E>>,
/// The payment address of the recipient
pub payment_address: Option<PaymentAddress<E>>,
/// The randomness used to hide the note commitment data
pub commitment_randomness: Option<E::Fs>,
/// The ephemeral secret key for DH with recipient
pub esk: Option<E::Fs>
}
/// Exposes a Pedersen commitment to the value as an
/// input to the circuit
fn expose_value_commitment<E, CS>(
mut cs: CS,
value_commitment: Option<ValueCommitment<E>>,
params: &E::Params
) -> Result<Vec<boolean::Boolean>, SynthesisError>
where E: JubjubEngine,
CS: ConstraintSystem<E>
{
// Booleanize the value into little-endian bit order
let value_bits = boolean::u64_into_boolean_vec_le(
cs.namespace(|| "value"),
value_commitment.as_ref().map(|c| c.value)
)?;
// Compute the note value in the exponent
let gv = ecc::fixed_base_multiplication(
cs.namespace(|| "compute the value in the exponent"),
FixedGenerators::ValueCommitmentValue,
&value_bits,
params
)?;
// Booleanize the randomness. This does not ensure
// the bit representation is "in the field" because
// it doesn't matter for security.
let hr = boolean::field_into_boolean_vec_le(
cs.namespace(|| "hr"),
value_commitment.as_ref().map(|c| c.randomness)
)?;
// Compute the randomness in the exponent
let hr = ecc::fixed_base_multiplication(
cs.namespace(|| "computation of randomization for value commitment"),
FixedGenerators::ValueCommitmentRandomness,
&hr,
params
)?;
// Compute the Pedersen commitment to the value
let gvhr = gv.add(
cs.namespace(|| "computation of value commitment"),
&hr,
params
)?;
// Expose the commitment as an input to the circuit
gvhr.inputize(cs.namespace(|| "commitment point"))?;
Ok(value_bits)
}
impl<'a, E: JubjubEngine> Circuit<E> for Spend<'a, E> {
fn synthesize<CS: ConstraintSystem<E>>(self, cs: &mut CS) -> Result<(), SynthesisError>
{
let value_bits = expose_value_commitment(
cs.namespace(|| "value commitment"),
self.value_commitment,
self.params
)?;
// Compute rk = [rsk] ProvingPublicKey
let rk;
{
// Witness rsk as bits
let rsk = boolean::field_into_boolean_vec_le(
cs.namespace(|| "rsk"),
self.proof_generation_key.as_ref().map(|k| k.rsk.clone())
)?;
// NB: We don't ensure that the bit representation of rsk
// is "in the field" (Fs) because it's not used except to
// demonstrate the prover knows it. If they know a
// congruency then that's equivalent.
// Compute rk = [rsk] ProvingPublicKey
rk = ecc::fixed_base_multiplication(
cs.namespace(|| "computation of rk"),
FixedGenerators::ProofGenerationKey,
&rsk,
self.params
)?;
}
// Prover witnesses ak (ensures that it's on the curve)
let ak = ecc::EdwardsPoint::witness(
cs.namespace(|| "ak"),
self.proof_generation_key.as_ref().map(|k| k.ak.clone()),
self.params
)?;
// There are no sensible attacks on small order points
// of ak (that we're aware of!) but it's a cheap check,
// so we do it.
ak.assert_not_small_order(
cs.namespace(|| "ak not small order"),
self.params
)?;
// Unpack ak and rk for input to BLAKE2s
// This is the "viewing key" preimage for CRH^ivk
let mut vk = vec![];
vk.extend(
ak.repr(cs.namespace(|| "representation of ak"))?
);
// This is the nullifier randomness preimage for PRF^nr
let mut nr_preimage = vec![];
// Extend vk and nr preimages with the representation of
// rk.
{
let repr_rk = rk.repr(
cs.namespace(|| "representation of rk")
)?;
vk.extend(repr_rk.iter().cloned());
nr_preimage.extend(repr_rk);
}
assert_eq!(vk.len(), 512);
assert_eq!(nr_preimage.len(), 256);
// Compute the incoming viewing key ivk
let mut ivk = blake2s::blake2s(
cs.namespace(|| "computation of ivk"),
&vk,
constants::CRH_IVK_PERSONALIZATION
)?;
// Little endian bit order
ivk.reverse();
// drop_5 to ensure it's in the field
ivk.truncate(E::Fs::CAPACITY as usize);
// Witness g_d. Ensures the point is on the
// curve, but not its order. If the prover
// manages to witness a commitment in the
// tree, then the Output circuit would have
// already guaranteed this.
let g_d = {
// This binding is to avoid a weird edge case in Rust's
// ownership/borrowing rules. self is partially moved
// above, but the closure for and_then will have to
// move self (or a reference to self) to reference
// self.params, so we have to copy self.params here.
let params = self.params;
ecc::EdwardsPoint::witness(
cs.namespace(|| "witness g_d"),
self.payment_address.as_ref().and_then(|a| a.g_d(params)),
self.params
)?
};
// Check that g_d is not small order. Technically, this check
// is already done in the Output circuit, and this proof ensures
// g_d is bound to a product of that check, but for defense in
// depth let's check it anyway. It's cheap.
g_d.assert_not_small_order(cs.namespace(|| "g_d not small order"), self.params)?;
// Compute pk_d = g_d^ivk
let pk_d = g_d.mul(
cs.namespace(|| "compute pk_d"),
&ivk,
self.params
)?;
// Compute note contents
// value (in big endian) followed by g_d and pk_d
let mut note_contents = vec![];
note_contents.extend(value_bits.into_iter().rev());
note_contents.extend(
g_d.repr(cs.namespace(|| "representation of g_d"))?
);
note_contents.extend(
pk_d.repr(cs.namespace(|| "representation of pk_d"))?
);
assert_eq!(
note_contents.len(),
64 + // value
256 + // g_d
256 // p_d
);
// Compute the hash of the note contents
let mut cm = pedersen_hash::pedersen_hash(
cs.namespace(|| "note content hash"),
pedersen_hash::Personalization::NoteCommitment,
&note_contents,
self.params
)?;
{
// Booleanize the randomness for the note commitment
let cmr = boolean::field_into_boolean_vec_le(
cs.namespace(|| "cmr"),
self.commitment_randomness
)?;
// Compute the note commitment randomness in the exponent
let cmr = ecc::fixed_base_multiplication(
cs.namespace(|| "computation of commitment randomness"),
FixedGenerators::NoteCommitmentRandomness,
&cmr,
self.params
)?;
// Randomize the note commitment. Pedersen hashes are not
// themselves hiding commitments.
cm = cm.add(
cs.namespace(|| "randomization of note commitment"),
&cmr,
self.params
)?;
}
let tree_depth = self.auth_path.len();
// This will store (least significant bit first)
// the position of the note in the tree, for use
// in nullifier computation.
let mut position_bits = vec![];
// This is an injective encoding, as cur is a
// point in the prime order subgroup.
let mut cur = cm.get_x().clone();
for (i, e) in self.auth_path.into_iter().enumerate() {
let cs = &mut cs.namespace(|| format!("merkle tree hash {}", i));
// Determines if the current subtree is the "right" leaf at this
// depth of the tree.
let cur_is_right = boolean::Boolean::from(boolean::AllocatedBit::alloc(
cs.namespace(|| "position bit"),
e.map(|e| e.1)
)?);
// Push this boolean for nullifier computation later
position_bits.push(cur_is_right.clone());
// Witness the authentication path element adjacent
// at this depth.
let path_element = num::AllocatedNum::alloc(
cs.namespace(|| "path element"),
|| {
Ok(e.get()?.0)
}
)?;
// Swap the two if the current subtree is on the right
let (xl, xr) = num::AllocatedNum::conditionally_reverse(
cs.namespace(|| "conditional reversal of preimage"),
&cur,
&path_element,
&cur_is_right
)?;
// We don't need to be strict, because the function is
// collision-resistant. If the prover witnesses a congruency,
// they will be unable to find an authentication path in the
// tree with high probability.
let mut preimage = vec![];
preimage.extend(xl.into_bits_le(cs.namespace(|| "xl into bits"))?);
preimage.extend(xr.into_bits_le(cs.namespace(|| "xr into bits"))?);
// Compute the new subtree value
cur = pedersen_hash::pedersen_hash(
cs.namespace(|| "computation of pedersen hash"),
pedersen_hash::Personalization::MerkleTree(i),
&preimage,
self.params
)?.get_x().clone(); // Injective encoding
}
assert_eq!(position_bits.len(), tree_depth);
// Expose the anchor
cur.inputize(cs.namespace(|| "anchor"))?;
// Compute the cm + g^position for preventing
// faerie gold attacks
{
// Compute the position in the exponent
let position = ecc::fixed_base_multiplication(
cs.namespace(|| "g^position"),
FixedGenerators::NullifierPosition,
&position_bits,
self.params
)?;
// Add the position to the commitment
cm = cm.add(
cs.namespace(|| "faerie gold prevention"),
&position,
self.params
)?;
}
// Let's compute nr = BLAKE2s(rk || cm + position)
nr_preimage.extend(
cm.repr(cs.namespace(|| "representation of cm"))?
);
assert_eq!(nr_preimage.len(), 512);
// Compute nr
let mut nr = blake2s::blake2s(
cs.namespace(|| "nr computation"),
&nr_preimage,
constants::PRF_NR_PERSONALIZATION
)?;
// Little endian bit order
nr.reverse();
// We want the randomization in the field to
// simplify outside code.
// TODO: This isn't uniformly random.
nr.truncate(E::Fs::CAPACITY as usize);
// Compute nullifier
let nf = ak.mul(
cs.namespace(|| "computation of nf"),
&nr,
self.params
)?;
// Expose the nullifier publicly
nf.inputize(cs.namespace(|| "nullifier"))?;
Ok(())
}
}
impl<'a, E: JubjubEngine> Circuit<E> for Output<'a, E> {
fn synthesize<CS: ConstraintSystem<E>>(self, cs: &mut CS) -> Result<(), SynthesisError>
{
let value_bits = expose_value_commitment(
cs.namespace(|| "value commitment"),
self.value_commitment,
self.params
)?;
// Let's start to construct our note, which contains
// value (big endian)
let mut note_contents = vec![];
note_contents.extend(value_bits.into_iter().rev());
// Let's deal with g_d
{
let params = self.params;
// Prover witnesses g_d, ensuring it's on the
// curve.
let g_d = ecc::EdwardsPoint::witness(
cs.namespace(|| "witness g_d"),
self.payment_address.as_ref().and_then(|a| a.g_d(params)),
self.params
)?;
// g_d is ensured to be large order. The relationship
// between g_d and pk_d ultimately binds ivk to the
// note. If this were a small order point, it would
// not do this correctly, and the prover could
// double-spend by finding random ivk's that satisfy
// the relationship.
//
// Further, if it were small order, epk would be
// small order too!
g_d.assert_not_small_order(
cs.namespace(|| "g_d not small order"),
self.params
)?;
// Extend our note contents with the representation of
// g_d.
note_contents.extend(
g_d.repr(cs.namespace(|| "representation of g_d"))?
);
// Booleanize our ephemeral secret key
let esk = boolean::field_into_boolean_vec_le(
cs.namespace(|| "esk"),
self.esk
)?;
// Create the ephemeral public key from g_d.
let epk = g_d.mul(
cs.namespace(|| "epk computation"),
&esk,
self.params
)?;
// Expose epk publicly.
epk.inputize(cs.namespace(|| "epk"))?;
}
// Now let's deal with pk_d. We don't do any checks and
// essentially allow the prover to witness any 256 bits
// they would like.
{
// Just grab pk_d from the witness
let pk_d = self.payment_address.as_ref().map(|e| e.pk_d.into_xy());
// Witness the y-coordinate, encoded as little
// endian bits (to match the representation)
let y_contents = boolean::field_into_boolean_vec_le(
cs.namespace(|| "pk_d bits of y"),
pk_d.map(|e| e.1)
)?;
// Witness the sign bit
let sign_bit = boolean::Boolean::from(boolean::AllocatedBit::alloc(
cs.namespace(|| "pk_d bit of x"),
pk_d.map(|e| e.0.into_repr().is_odd())
)?);
// Extend the note with pk_d representation
note_contents.extend(y_contents);
note_contents.push(sign_bit);
}
assert_eq!(
note_contents.len(),
64 + // value
256 + // g_d
256 // p_d
);
// Compute the hash of the note contents
let mut cm = pedersen_hash::pedersen_hash(
cs.namespace(|| "note content hash"),
pedersen_hash::Personalization::NoteCommitment,
&note_contents,
self.params
)?;
{
// Booleanize the randomness
let cmr = boolean::field_into_boolean_vec_le(
cs.namespace(|| "cmr"),
self.commitment_randomness
)?;
// Compute the note commitment randomness in the exponent
let cmr = ecc::fixed_base_multiplication(
cs.namespace(|| "computation of commitment randomness"),
FixedGenerators::NoteCommitmentRandomness,
&cmr,
self.params
)?;
// Randomize our note commitment
cm = cm.add(
cs.namespace(|| "randomization of note commitment"),
&cmr,
self.params
)?;
}
// Only the x-coordinate of the output is revealed,
// since we know it is prime order, and we know that
// the x-coordinate is an injective encoding for
// prime-order elements.
cm.get_x().inputize(cs.namespace(|| "commitment"))?;
Ok(())
}
}
#[test]
fn test_input_circuit_with_bls12_381() {
use pairing::{Field, BitIterator};
use pairing::bls12_381::*;
use rand::{SeedableRng, Rng, XorShiftRng};
use ::circuit::test::*;
use jubjub::{JubjubBls12, fs, edwards};
let params = &JubjubBls12::new();
let rng = &mut XorShiftRng::from_seed([0x3dbe6259, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
let tree_depth = 32;
let value_commitment = ValueCommitment {
value: rng.gen(),
randomness: rng.gen()
};
let rsk: fs::Fs = rng.gen();
let ak = edwards::Point::rand(rng, params).mul_by_cofactor(params);
let proof_generation_key = ::primitives::ProofGenerationKey {
ak: ak.clone(),
rsk: rsk.clone()
};
let viewing_key = proof_generation_key.into_viewing_key(params);
let payment_address;
loop {
let diversifier = ::primitives::Diversifier(rng.gen());
if let Some(p) = viewing_key.into_payment_address(
diversifier,
params
)
{
payment_address = p;
break;
}
}
let g_d = payment_address.diversifier.g_d(params).unwrap();
let commitment_randomness: fs::Fs = rng.gen();
let auth_path = vec![Some((rng.gen(), rng.gen())); tree_depth];
{
let mut cs = TestConstraintSystem::<Bls12>::new();
let instance = Spend {
params: params,
value_commitment: Some(value_commitment.clone()),
proof_generation_key: Some(proof_generation_key.clone()),
payment_address: Some(payment_address.clone()),
commitment_randomness: Some(commitment_randomness),
auth_path: auth_path.clone()
};
instance.synthesize(&mut cs).unwrap();
assert!(cs.is_satisfied());
assert_eq!(cs.num_constraints(), 101018);
assert_eq!(cs.hash(), "eedcef5fd638e0168ae4d53ac58df66f0acdabea46749cc5f4b39459c8377804");
let expected_value_cm = value_commitment.cm(params).into_xy();
assert_eq!(cs.num_inputs(), 6);
assert_eq!(cs.get_input(0, "ONE"), Fr::one());
assert_eq!(cs.get_input(1, "value commitment/commitment point/x/input variable"), expected_value_cm.0);
assert_eq!(cs.get_input(2, "value commitment/commitment point/y/input variable"), expected_value_cm.1);
let note = ::primitives::Note {
value: value_commitment.value,
g_d: g_d.clone(),
pk_d: payment_address.pk_d.clone(),
r: commitment_randomness.clone()
};
let mut position = 0u64;
let mut cur = note.cm(params);
assert_eq!(cs.get("randomization of note commitment/x3/num"), cur);
for (i, val) in auth_path.into_iter().enumerate()
{
let (uncle, b) = val.unwrap();
let mut lhs = cur;
let mut rhs = uncle;
if b {
::std::mem::swap(&mut lhs, &mut rhs);
}
let mut lhs: Vec<bool> = BitIterator::new(lhs.into_repr()).collect();
let mut rhs: Vec<bool> = BitIterator::new(rhs.into_repr()).collect();
lhs.reverse();
rhs.reverse();
cur = ::pedersen_hash::pedersen_hash::<Bls12, _>(
::pedersen_hash::Personalization::MerkleTree(i),
lhs.into_iter()
.take(Fr::NUM_BITS as usize)
.chain(rhs.into_iter().take(Fr::NUM_BITS as usize)),
params
).into_xy().0;
if b {
position |= 1 << i;
}
}
let expected_nf = note.nf(&viewing_key, position, params);
let expected_nf_xy = expected_nf.into_xy();
assert_eq!(cs.get_input(3, "anchor/input variable"), cur);
assert_eq!(cs.get_input(4, "nullifier/x/input variable"), expected_nf_xy.0);
assert_eq!(cs.get_input(5, "nullifier/y/input variable"), expected_nf_xy.1);
}
}
#[test]
fn test_output_circuit_with_bls12_381() {
use pairing::{Field};
use pairing::bls12_381::*;
use rand::{SeedableRng, Rng, XorShiftRng};
use ::circuit::test::*;
use jubjub::{JubjubBls12, fs, edwards};
let params = &JubjubBls12::new();
let rng = &mut XorShiftRng::from_seed([0x3dbe6258, 0x8d313d76, 0x3237db17, 0xe5bc0654]);
let value_commitment = ValueCommitment {
value: rng.gen(),
randomness: rng.gen()
};
let rsk: fs::Fs = rng.gen();
let ak = edwards::Point::rand(rng, params).mul_by_cofactor(params);
let proof_generation_key = ::primitives::ProofGenerationKey {
ak: ak.clone(),
rsk: rsk.clone()
};
let viewing_key = proof_generation_key.into_viewing_key(params);
let payment_address;
loop {
let diversifier = ::primitives::Diversifier(rng.gen());
if let Some(p) = viewing_key.into_payment_address(
diversifier,
params
)
{
payment_address = p;
break;
}
}
let commitment_randomness: fs::Fs = rng.gen();
let esk: fs::Fs = rng.gen();
{
let mut cs = TestConstraintSystem::<Bls12>::new();
let instance = Output {
params: params,
value_commitment: Some(value_commitment.clone()),
payment_address: Some(payment_address.clone()),
commitment_randomness: Some(commitment_randomness),
esk: Some(esk.clone())
};
instance.synthesize(&mut cs).unwrap();
assert!(cs.is_satisfied());
assert_eq!(cs.num_constraints(), 7827);
assert_eq!(cs.hash(), "2896f259ad7a50c83604976ee9362358396d547b70f2feaf91d82d287e4ffc1d");
let expected_cm = payment_address.create_note(
value_commitment.value,
commitment_randomness,
params
).expect("should be valid").cm(params);
let expected_value_cm = value_commitment.cm(params).into_xy();
let expected_epk = payment_address.g_d(params).expect("should be valid").mul(esk, params);
let expected_epk_xy = expected_epk.into_xy();
assert_eq!(cs.num_inputs(), 6);
assert_eq!(cs.get_input(0, "ONE"), Fr::one());
assert_eq!(cs.get_input(1, "value commitment/commitment point/x/input variable"), expected_value_cm.0);
assert_eq!(cs.get_input(2, "value commitment/commitment point/y/input variable"), expected_value_cm.1);
assert_eq!(cs.get_input(3, "epk/x/input variable"), expected_epk_xy.0);
assert_eq!(cs.get_input(4, "epk/y/input variable"), expected_epk_xy.1);
assert_eq!(cs.get_input(5, "commitment/input variable"), expected_cm);
}
}

14
src/circuit/test/mod.rs
View File

@@ -294,6 +294,20 @@ impl<E: Engine> TestConstraintSystem<E> {
} }
} }
pub fn verify(&self, expected: &[E::Fr]) -> bool
{
assert_eq!(expected.len() + 1, self.inputs.len());
for (a, b) in self.inputs.iter().skip(1).zip(expected.iter())
{
if &a.0 != b {
return false
}
}
return true;
}
pub fn num_inputs(&self) -> usize { pub fn num_inputs(&self) -> usize {
self.inputs.len() self.inputs.len()
} }

58
src/circuit/uint32.rs
View File

@@ -15,6 +15,8 @@ use super::boolean::{
AllocatedBit AllocatedBit
}; };
use super::multieq::MultiEq;
/// Represents an interpretation of 32 `Boolean` objects as an /// Represents an interpretation of 32 `Boolean` objects as an
/// unsigned integer. /// unsigned integer.
#[derive(Clone)] #[derive(Clone)]
@@ -188,12 +190,13 @@ impl UInt32 {
} }
/// Perform modular addition of several `UInt32` objects. /// Perform modular addition of several `UInt32` objects.
pub fn addmany<E, CS>( pub fn addmany<E, CS, M>(
mut cs: CS, mut cs: M,
operands: &[Self] operands: &[Self]
) -> Result<Self, SynthesisError> ) -> Result<Self, SynthesisError>
where E: Engine, where E: Engine,
CS: ConstraintSystem<E> CS: ConstraintSystem<E>,
M: ConstraintSystem<E, Root=MultiEq<E, CS>>
{ {
// Make some arbitrary bounds for ourselves to avoid overflows // Make some arbitrary bounds for ourselves to avoid overflows
// in the scalar field // in the scalar field
@@ -208,7 +211,8 @@ impl UInt32 {
// Keep track of the resulting value // Keep track of the resulting value
let mut result_value = Some(0u64); let mut result_value = Some(0u64);
// This is a linear combination that we will enforce to be "zero" // This is a linear combination that we will enforce to equal the
// output
let mut lc = LinearCombination::zero(); let mut lc = LinearCombination::zero();
let mut all_constants = true; let mut all_constants = true;
@@ -231,25 +235,9 @@ impl UInt32 {
// the linear combination // the linear combination
let mut coeff = E::Fr::one(); let mut coeff = E::Fr::one();
for bit in &op.bits { for bit in &op.bits {
match bit { lc = lc + &bit.lc(CS::one(), coeff);
&Boolean::Is(ref bit) => {
all_constants = false;
// Add coeff * bit all_constants &= bit.is_constant();
lc = lc + (coeff, bit.get_variable());
},
&Boolean::Not(ref bit) => {
all_constants = false;
// Add coeff * (1 - bit) = coeff * ONE - coeff * bit
lc = lc + (coeff, CS::one()) - (coeff, bit.get_variable());
},
&Boolean::Constant(bit) => {
if bit {
lc = lc + (coeff, CS::one());
}
}
}
coeff.double(); coeff.double();
} }
@@ -268,6 +256,10 @@ impl UInt32 {
// Storage area for the resulting bits // Storage area for the resulting bits
let mut result_bits = vec![]; let mut result_bits = vec![];
// Linear combination representing the output,
// for comparison with the sum of the operands
let mut result_lc = LinearCombination::zero();
// Allocate each bit of the result // Allocate each bit of the result
let mut coeff = E::Fr::one(); let mut coeff = E::Fr::one();
let mut i = 0; let mut i = 0;
@@ -278,8 +270,8 @@ impl UInt32 {
result_value.map(|v| (v >> i) & 1 == 1) result_value.map(|v| (v >> i) & 1 == 1)
)?; )?;
// Subtract this bit from the linear combination to ensure the sums balance out // Add this bit to the result combination
lc = lc - (coeff, b.get_variable()); result_lc = result_lc + (coeff, b.get_variable());
result_bits.push(b.into()); result_bits.push(b.into());
@@ -288,13 +280,8 @@ impl UInt32 {
coeff.double(); coeff.double();
} }
// Enforce that the linear combination equals zero // Enforce equality between the sum and result
cs.enforce( cs.get_root().enforce_equal(i, &lc, &result_lc);
|| "modular addition",
|lc| lc,
|lc| lc,
|_| lc
);
// Discard carry bits that we don't care about // Discard carry bits that we don't care about
result_bits.truncate(32); result_bits.truncate(32);
@@ -315,6 +302,7 @@ mod test {
use pairing::{Field}; use pairing::{Field};
use ::circuit::test::*; use ::circuit::test::*;
use bellman::{ConstraintSystem}; use bellman::{ConstraintSystem};
use circuit::multieq::MultiEq;
#[test] #[test]
fn test_uint32_from_bits() { fn test_uint32_from_bits() {
@@ -406,7 +394,11 @@ mod test {
let mut expected = a.wrapping_add(b).wrapping_add(c); let mut expected = a.wrapping_add(b).wrapping_add(c);
let r = {
let mut cs = MultiEq::new(&mut cs);
let r = UInt32::addmany(cs.namespace(|| "addition"), &[a_bit, b_bit, c_bit]).unwrap(); let r = UInt32::addmany(cs.namespace(|| "addition"), &[a_bit, b_bit, c_bit]).unwrap();
r
};
assert!(r.value == Some(expected)); assert!(r.value == Some(expected));
@@ -444,7 +436,11 @@ mod test {
let d_bit = UInt32::alloc(cs.namespace(|| "d_bit"), Some(d)).unwrap(); let d_bit = UInt32::alloc(cs.namespace(|| "d_bit"), Some(d)).unwrap();
let r = a_bit.xor(cs.namespace(|| "xor"), &b_bit).unwrap(); let r = a_bit.xor(cs.namespace(|| "xor"), &b_bit).unwrap();
let r = {
let mut cs = MultiEq::new(&mut cs);
let r = UInt32::addmany(cs.namespace(|| "addition"), &[r, c_bit, d_bit]).unwrap(); let r = UInt32::addmany(cs.namespace(|| "addition"), &[r, c_bit, d_bit]).unwrap();
r
};
assert!(cs.is_satisfied()); assert!(cs.is_satisfied());