Squashed 'src/secp256k1/' changes from ad2028f..b0210a9

b0210a9 Merge pull request #135
ee3eb4b Fix a memory leak and add a number of small tests.
4d879a3 Merge pull request #134
d5e8362 Merge pull request #127
7b92cf6 Merge pull request #132
0bf70a5 Merge pull request #133
29ae131 Make scalar_add_bit test's overflow detection exact
9048def Avoid undefined shift behaviour
efb7d4b Use constant-time conditional moves instead of byte slicing
d220062 Merge pull request #131
82f9254 Fix typo
601ca04 Merge pull request #129
35399e0 Bugfix: b is restricted, not r
c35ff1e Convert lambda splitter to pure scalar code.
cc604e9 Avoid division when decomposing scalars
ff8746d Add secp256k1_scalar_mul_shift_var
bd313f7 Merge pull request #119
276f987 Merge pull request #124
25d125e Merge pull request #126
24b3c65 Add a test case for ECDSA recomputing infinity
32600e5 Add a test for r >= order signature handling
4d4eeea Make secp256k1_fe_mul_inner use the r != property
be82e92 Require that r and b are different for field multiplication.
597128d Make num optional
659b554 Make constant initializers independent from num
0af5b47 Merge pull request #120
e2e8a36 Merge pull request #117
c76be9e Remove unused num functions
4285a98 Move lambda-splitting code to scalar.
f24041d Switch all EC/ECDSA logic from num to scalar
6794be6 Add scalar splitting functions
d1502eb Add secp256k1_scalar_inverse_var which delegates to GMP
b5c9ee7 Make test_point_times_order test meaningful again
0b73059 Switch wnaf splitting from num-based to scalar-based
1e6c77c Generalize secp256k1_scalar_get_bits
5213207 Add secp256k1_scalar_add_bit
3c0ae43 Merge pull request #122
6e05287 Do signature recovery/verification with 4 possible recid case
e3d692f Explain why no y=0 check is necessary for doubling
f7dc1c6 Optimize doubling: secp256k1 has no y=0 point
666d3b5 Merge pull request #121
2a54f9b Correct typo in comment
9d64145 Merge pull request #114
99f0728 Fix secp256k1_num_set_bin handling of 0
d907ebc Add bounds checking to field element setters
bb2cd94 Merge pull request #116
665775b Don't split the g factor when not using endomorphism
9431d6b Merge pull request #115
e2274c5 build: osx: attempt to work with homebrew keg-only packages

git-subtree-dir: src/secp256k1
git-subtree-split: b0210a95da433e048a11d298efbcc14eb423c95f
This commit is contained in:
Pieter Wuille
2014-12-04 19:17:07 +01:00
parent d48555b36a
commit 87bddb7a3a
30 changed files with 1255 additions and 787 deletions

View File

@@ -45,9 +45,31 @@ SECP256K1_INLINE static void secp256k1_scalar_clear(secp256k1_scalar_t *r) {
r->d[7] = 0;
}
SECP256K1_INLINE static int secp256k1_scalar_get_bits(const secp256k1_scalar_t *a, int offset, int count) {
VERIFY_CHECK((offset + count - 1) / 32 == offset / 32);
return (a->d[offset / 32] >> (offset % 32)) & ((1 << count) - 1);
SECP256K1_INLINE static void secp256k1_scalar_set_int(secp256k1_scalar_t *r, unsigned int v) {
r->d[0] = v;
r->d[1] = 0;
r->d[2] = 0;
r->d[3] = 0;
r->d[4] = 0;
r->d[5] = 0;
r->d[6] = 0;
r->d[7] = 0;
}
SECP256K1_INLINE static unsigned int secp256k1_scalar_get_bits(const secp256k1_scalar_t *a, unsigned int offset, unsigned int count) {
VERIFY_CHECK((offset + count - 1) >> 5 == offset >> 5);
return (a->d[offset >> 5] >> (offset & 0x1F)) & ((1 << count) - 1);
}
SECP256K1_INLINE static unsigned int secp256k1_scalar_get_bits_var(const secp256k1_scalar_t *a, unsigned int offset, unsigned int count) {
VERIFY_CHECK(count < 32);
VERIFY_CHECK(offset + count <= 256);
if ((offset + count - 1) >> 5 == offset >> 5) {
return secp256k1_scalar_get_bits(a, offset, count);
} else {
VERIFY_CHECK((offset >> 5) + 1 < 8);
return ((a->d[offset >> 5] >> (offset & 0x1F)) | (a->d[(offset >> 5) + 1] << (32 - (offset & 0x1F)))) & ((((uint32_t)1) << count) - 1);
}
}
SECP256K1_INLINE static int secp256k1_scalar_check_overflow(const secp256k1_scalar_t *a) {
@@ -89,7 +111,7 @@ SECP256K1_INLINE static int secp256k1_scalar_reduce(secp256k1_scalar_t *r, uint3
return overflow;
}
static void secp256k1_scalar_add(secp256k1_scalar_t *r, const secp256k1_scalar_t *a, const secp256k1_scalar_t *b) {
static int secp256k1_scalar_add(secp256k1_scalar_t *r, const secp256k1_scalar_t *a, const secp256k1_scalar_t *b) {
uint64_t t = (uint64_t)a->d[0] + b->d[0];
r->d[0] = t & 0xFFFFFFFFULL; t >>= 32;
t += (uint64_t)a->d[1] + b->d[1];
@@ -106,7 +128,34 @@ static void secp256k1_scalar_add(secp256k1_scalar_t *r, const secp256k1_scalar_t
r->d[6] = t & 0xFFFFFFFFULL; t >>= 32;
t += (uint64_t)a->d[7] + b->d[7];
r->d[7] = t & 0xFFFFFFFFULL; t >>= 32;
secp256k1_scalar_reduce(r, t + secp256k1_scalar_check_overflow(r));
int overflow = t + secp256k1_scalar_check_overflow(r);
VERIFY_CHECK(overflow == 0 || overflow == 1);
secp256k1_scalar_reduce(r, overflow);
return overflow;
}
static void secp256k1_scalar_add_bit(secp256k1_scalar_t *r, unsigned int bit) {
VERIFY_CHECK(bit < 256);
uint64_t t = (uint64_t)r->d[0] + (((uint32_t)((bit >> 5) == 0)) << (bit & 0x1F));
r->d[0] = t & 0xFFFFFFFFULL; t >>= 32;
t += (uint64_t)r->d[1] + (((uint32_t)((bit >> 5) == 1)) << (bit & 0x1F));
r->d[1] = t & 0xFFFFFFFFULL; t >>= 32;
t += (uint64_t)r->d[2] + (((uint32_t)((bit >> 5) == 2)) << (bit & 0x1F));
r->d[2] = t & 0xFFFFFFFFULL; t >>= 32;
t += (uint64_t)r->d[3] + (((uint32_t)((bit >> 5) == 3)) << (bit & 0x1F));
r->d[3] = t & 0xFFFFFFFFULL; t >>= 32;
t += (uint64_t)r->d[4] + (((uint32_t)((bit >> 5) == 4)) << (bit & 0x1F));
r->d[4] = t & 0xFFFFFFFFULL; t >>= 32;
t += (uint64_t)r->d[5] + (((uint32_t)((bit >> 5) == 5)) << (bit & 0x1F));
r->d[5] = t & 0xFFFFFFFFULL; t >>= 32;
t += (uint64_t)r->d[6] + (((uint32_t)((bit >> 5) == 6)) << (bit & 0x1F));
r->d[6] = t & 0xFFFFFFFFULL; t >>= 32;
t += (uint64_t)r->d[7] + (((uint32_t)((bit >> 5) == 7)) << (bit & 0x1F));
r->d[7] = t & 0xFFFFFFFFULL;
#ifdef VERIFY
VERIFY_CHECK((t >> 32) == 0);
VERIFY_CHECK(secp256k1_scalar_check_overflow(r) == 0);
#endif
}
static void secp256k1_scalar_set_b32(secp256k1_scalar_t *r, const unsigned char *b32, int *overflow) {
@@ -405,12 +454,10 @@ static void secp256k1_scalar_reduce_512(secp256k1_scalar_t *r, const uint32_t *l
secp256k1_scalar_reduce(r, c + secp256k1_scalar_check_overflow(r));
}
static void secp256k1_scalar_mul(secp256k1_scalar_t *r, const secp256k1_scalar_t *a, const secp256k1_scalar_t *b) {
static void secp256k1_scalar_mul_512(uint32_t l[16], const secp256k1_scalar_t *a, const secp256k1_scalar_t *b) {
/* 96 bit accumulator. */
uint32_t c0 = 0, c1 = 0, c2 = 0;
uint32_t l[16];
/* l[0..15] = a[0..7] * b[0..7]. */
muladd_fast(a->d[0], b->d[0]);
extract_fast(l[0]);
@@ -493,16 +540,12 @@ static void secp256k1_scalar_mul(secp256k1_scalar_t *r, const secp256k1_scalar_t
extract_fast(l[14]);
VERIFY_CHECK(c1 == 0);
l[15] = c0;
secp256k1_scalar_reduce_512(r, l);
}
static void secp256k1_scalar_sqr(secp256k1_scalar_t *r, const secp256k1_scalar_t *a) {
static void secp256k1_scalar_sqr_512(uint32_t l[16], const secp256k1_scalar_t *a) {
/* 96 bit accumulator. */
uint32_t c0 = 0, c1 = 0, c2 = 0;
uint32_t l[16];
/* l[0..15] = a[0..7]^2. */
muladd_fast(a->d[0], a->d[0]);
extract_fast(l[0]);
@@ -557,8 +600,6 @@ static void secp256k1_scalar_sqr(secp256k1_scalar_t *r, const secp256k1_scalar_t
extract_fast(l[14]);
VERIFY_CHECK(c1 == 0);
l[15] = c0;
secp256k1_scalar_reduce_512(r, l);
}
#undef sumadd
@@ -569,4 +610,59 @@ static void secp256k1_scalar_sqr(secp256k1_scalar_t *r, const secp256k1_scalar_t
#undef extract
#undef extract_fast
static void secp256k1_scalar_mul(secp256k1_scalar_t *r, const secp256k1_scalar_t *a, const secp256k1_scalar_t *b) {
uint32_t l[16];
secp256k1_scalar_mul_512(l, a, b);
secp256k1_scalar_reduce_512(r, l);
}
static void secp256k1_scalar_sqr(secp256k1_scalar_t *r, const secp256k1_scalar_t *a) {
uint32_t l[16];
secp256k1_scalar_sqr_512(l, a);
secp256k1_scalar_reduce_512(r, l);
}
static void secp256k1_scalar_split_128(secp256k1_scalar_t *r1, secp256k1_scalar_t *r2, const secp256k1_scalar_t *a) {
r1->d[0] = a->d[0];
r1->d[1] = a->d[1];
r1->d[2] = a->d[2];
r1->d[3] = a->d[3];
r1->d[4] = 0;
r1->d[5] = 0;
r1->d[6] = 0;
r1->d[7] = 0;
r2->d[0] = a->d[4];
r2->d[1] = a->d[5];
r2->d[2] = a->d[6];
r2->d[3] = a->d[7];
r2->d[4] = 0;
r2->d[5] = 0;
r2->d[6] = 0;
r2->d[7] = 0;
}
SECP256K1_INLINE static int secp256k1_scalar_eq(const secp256k1_scalar_t *a, const secp256k1_scalar_t *b) {
return ((a->d[0] ^ b->d[0]) | (a->d[1] ^ b->d[1]) | (a->d[2] ^ b->d[2]) | (a->d[3] ^ b->d[3]) | (a->d[4] ^ b->d[4]) | (a->d[5] ^ b->d[5]) | (a->d[6] ^ b->d[6]) | (a->d[7] ^ b->d[7])) == 0;
}
SECP256K1_INLINE static void secp256k1_scalar_mul_shift_var(secp256k1_scalar_t *r, const secp256k1_scalar_t *a, const secp256k1_scalar_t *b, unsigned int shift) {
VERIFY_CHECK(shift >= 256);
uint32_t l[16];
secp256k1_scalar_mul_512(l, a, b);
unsigned int shiftlimbs = shift >> 5;
unsigned int shiftlow = shift & 0x1F;
unsigned int shifthigh = 32 - shiftlow;
r->d[0] = shift < 512 ? (l[0 + shiftlimbs] >> shiftlow | (shift < 480 && shiftlow ? (l[1 + shiftlimbs] << shifthigh) : 0)) : 0;
r->d[1] = shift < 480 ? (l[1 + shiftlimbs] >> shiftlow | (shift < 448 && shiftlow ? (l[2 + shiftlimbs] << shifthigh) : 0)) : 0;
r->d[2] = shift < 448 ? (l[2 + shiftlimbs] >> shiftlow | (shift < 416 && shiftlow ? (l[3 + shiftlimbs] << shifthigh) : 0)) : 0;
r->d[3] = shift < 416 ? (l[3 + shiftlimbs] >> shiftlow | (shift < 384 && shiftlow ? (l[4 + shiftlimbs] << shifthigh) : 0)) : 0;
r->d[4] = shift < 384 ? (l[4 + shiftlimbs] >> shiftlow | (shift < 352 && shiftlow ? (l[5 + shiftlimbs] << shifthigh) : 0)) : 0;
r->d[5] = shift < 352 ? (l[5 + shiftlimbs] >> shiftlow | (shift < 320 && shiftlow ? (l[6 + shiftlimbs] << shifthigh) : 0)) : 0;
r->d[6] = shift < 320 ? (l[6 + shiftlimbs] >> shiftlow | (shift < 288 && shiftlow ? (l[7 + shiftlimbs] << shifthigh) : 0)) : 0;
r->d[7] = shift < 288 ? (l[7 + shiftlimbs] >> shiftlow) : 0;
if ((l[(shift - 1) >> 5] >> ((shift - 1) & 0x1f)) & 1) {
secp256k1_scalar_add_bit(r, 0);
}
}
#endif