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Merge commits 'b314cf28 1f1bb78b 40f50d0f c891c5c2 ea47c82e e7210393 c1b49664 5814d848 07687e81 10e6d29b d3e29db8 e2c9888e 4197d667 5e9a4d7a 77af1da9 1a81df82 1ad5185c efe85c70 79e09451 d373bf6d 74b7c3b5 a9db9f2d 44378867 3bf4d68f e4af41c6 ' into temp-merge-1249

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This commit is contained in:
Tim Ruffing
2024-01-18 10:25:34 +01:00
parent 0ffca6f794 e4af41c61b
commit e626f00d1e
53 changed files with 1550 additions and 1583 deletions
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150
src/scalar_8x32_impl.h
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@@ -61,7 +61,7 @@ SECP256K1_INLINE static void secp256k1_scalar_set_int(secp256k1_scalar *r, unsig
r->d[6] = 0;
r->d[7] = 0;
secp256k1_scalar_verify(r);
SECP256K1_SCALAR_VERIFY(r);
}
SECP256K1_INLINE static void secp256k1_scalar_set_u64(secp256k1_scalar *r, uint64_t v) {
@@ -76,14 +76,14 @@ SECP256K1_INLINE static void secp256k1_scalar_set_u64(secp256k1_scalar *r, uint6
}
SECP256K1_INLINE static unsigned int secp256k1_scalar_get_bits(const secp256k1_scalar *a, unsigned int offset, unsigned int count) {
secp256k1_scalar_verify(a);
SECP256K1_SCALAR_VERIFY(a);
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 *a, unsigned int offset, unsigned int count) {
secp256k1_scalar_verify(a);
SECP256K1_SCALAR_VERIFY(a);
VERIFY_CHECK(count < 32);
VERIFY_CHECK(offset + count <= 256);
@@ -134,15 +134,15 @@ SECP256K1_INLINE static int secp256k1_scalar_reduce(secp256k1_scalar *r, uint32_
t += (uint64_t)r->d[7];
r->d[7] = t & 0xFFFFFFFFUL;
secp256k1_scalar_verify(r);
SECP256K1_SCALAR_VERIFY(r);
return overflow;
}
static int secp256k1_scalar_add(secp256k1_scalar *r, const secp256k1_scalar *a, const secp256k1_scalar *b) {
int overflow;
uint64_t t = (uint64_t)a->d[0] + b->d[0];
secp256k1_scalar_verify(a);
secp256k1_scalar_verify(b);
SECP256K1_SCALAR_VERIFY(a);
SECP256K1_SCALAR_VERIFY(b);
r->d[0] = t & 0xFFFFFFFFULL; t >>= 32;
t += (uint64_t)a->d[1] + b->d[1];
@@ -163,14 +163,14 @@ static int secp256k1_scalar_add(secp256k1_scalar *r, const secp256k1_scalar *a,
VERIFY_CHECK(overflow == 0 || overflow == 1);
secp256k1_scalar_reduce(r, overflow);
secp256k1_scalar_verify(r);
SECP256K1_SCALAR_VERIFY(r);
return overflow;
}
static void secp256k1_scalar_cadd_bit(secp256k1_scalar *r, unsigned int bit, int flag) {
uint64_t t;
volatile int vflag = flag;
secp256k1_scalar_verify(r);
SECP256K1_SCALAR_VERIFY(r);
VERIFY_CHECK(bit < 256);
bit += ((uint32_t) vflag - 1) & 0x100; /* forcing (bit >> 5) > 7 makes this a noop */
@@ -191,10 +191,8 @@ static void secp256k1_scalar_cadd_bit(secp256k1_scalar *r, unsigned int bit, int
t += (uint64_t)r->d[7] + (((uint32_t)((bit >> 5) == 7)) << (bit & 0x1F));
r->d[7] = t & 0xFFFFFFFFULL;
secp256k1_scalar_verify(r);
#ifdef VERIFY
SECP256K1_SCALAR_VERIFY(r);
VERIFY_CHECK((t >> 32) == 0);
#endif
}
static void secp256k1_scalar_set_b32(secp256k1_scalar *r, const unsigned char *b32, int *overflow) {
@@ -212,11 +210,11 @@ static void secp256k1_scalar_set_b32(secp256k1_scalar *r, const unsigned char *b
*overflow = over;
}
secp256k1_scalar_verify(r);
SECP256K1_SCALAR_VERIFY(r);
}
static void secp256k1_scalar_get_b32(unsigned char *bin, const secp256k1_scalar* a) {
secp256k1_scalar_verify(a);
SECP256K1_SCALAR_VERIFY(a);
secp256k1_write_be32(&bin[0], a->d[7]);
secp256k1_write_be32(&bin[4], a->d[6]);
@@ -229,7 +227,7 @@ static void secp256k1_scalar_get_b32(unsigned char *bin, const secp256k1_scalar*
}
SECP256K1_INLINE static int secp256k1_scalar_is_zero(const secp256k1_scalar *a) {
secp256k1_scalar_verify(a);
SECP256K1_SCALAR_VERIFY(a);
return (a->d[0] | a->d[1] | a->d[2] | a->d[3] | a->d[4] | a->d[5] | a->d[6] | a->d[7]) == 0;
}
@@ -237,7 +235,7 @@ SECP256K1_INLINE static int secp256k1_scalar_is_zero(const secp256k1_scalar *a)
static void secp256k1_scalar_negate(secp256k1_scalar *r, const secp256k1_scalar *a) {
uint32_t nonzero = 0xFFFFFFFFUL * (secp256k1_scalar_is_zero(a) == 0);
uint64_t t = (uint64_t)(~a->d[0]) + SECP256K1_N_0 + 1;
secp256k1_scalar_verify(a);
SECP256K1_SCALAR_VERIFY(a);
r->d[0] = t & nonzero; t >>= 32;
t += (uint64_t)(~a->d[1]) + SECP256K1_N_1;
@@ -255,11 +253,59 @@ static void secp256k1_scalar_negate(secp256k1_scalar *r, const secp256k1_scalar
t += (uint64_t)(~a->d[7]) + SECP256K1_N_7;
r->d[7] = t & nonzero;
secp256k1_scalar_verify(r);
SECP256K1_SCALAR_VERIFY(r);
}
static void secp256k1_scalar_half(secp256k1_scalar *r, const secp256k1_scalar *a) {
/* Writing `/` for field division and `//` for integer division, we compute
*
* a/2 = (a - (a&1))/2 + (a&1)/2
* = (a >> 1) + (a&1 ? 1/2 : 0)
* = (a >> 1) + (a&1 ? n//2+1 : 0),
*
* where n is the group order and in the last equality we have used 1/2 = n//2+1 (mod n).
* For n//2, we have the constants SECP256K1_N_H_0, ...
*
* This sum does not overflow. The most extreme case is a = -2, the largest odd scalar. Here:
* - the left summand is: a >> 1 = (a - a&1)/2 = (n-2-1)//2 = (n-3)//2
* - the right summand is: a&1 ? n//2+1 : 0 = n//2+1 = (n-1)//2 + 2//2 = (n+1)//2
* Together they sum to (n-3)//2 + (n+1)//2 = (2n-2)//2 = n - 1, which is less than n.
*/
uint32_t mask = -(uint32_t)(a->d[0] & 1U);
uint64_t t = (uint32_t)((a->d[0] >> 1) | (a->d[1] << 31));
SECP256K1_SCALAR_VERIFY(a);
t += (SECP256K1_N_H_0 + 1U) & mask;
r->d[0] = t; t >>= 32;
t += (uint32_t)((a->d[1] >> 1) | (a->d[2] << 31));
t += SECP256K1_N_H_1 & mask;
r->d[1] = t; t >>= 32;
t += (uint32_t)((a->d[2] >> 1) | (a->d[3] << 31));
t += SECP256K1_N_H_2 & mask;
r->d[2] = t; t >>= 32;
t += (uint32_t)((a->d[3] >> 1) | (a->d[4] << 31));
t += SECP256K1_N_H_3 & mask;
r->d[3] = t; t >>= 32;
t += (uint32_t)((a->d[4] >> 1) | (a->d[5] << 31));
t += SECP256K1_N_H_4 & mask;
r->d[4] = t; t >>= 32;
t += (uint32_t)((a->d[5] >> 1) | (a->d[6] << 31));
t += SECP256K1_N_H_5 & mask;
r->d[5] = t; t >>= 32;
t += (uint32_t)((a->d[6] >> 1) | (a->d[7] << 31));
t += SECP256K1_N_H_6 & mask;
r->d[6] = t; t >>= 32;
r->d[7] = (uint32_t)t + (uint32_t)(a->d[7] >> 1) + (SECP256K1_N_H_7 & mask);
/* The line above only computed the bottom 32 bits of r->d[7]. Redo the computation
* in full 64 bits to make sure the top 32 bits are indeed zero. */
VERIFY_CHECK((t + (a->d[7] >> 1) + (SECP256K1_N_H_7 & mask)) >> 32 == 0);
SECP256K1_SCALAR_VERIFY(r);
}
SECP256K1_INLINE static int secp256k1_scalar_is_one(const secp256k1_scalar *a) {
secp256k1_scalar_verify(a);
SECP256K1_SCALAR_VERIFY(a);
return ((a->d[0] ^ 1) | a->d[1] | a->d[2] | a->d[3] | a->d[4] | a->d[5] | a->d[6] | a->d[7]) == 0;
}
@@ -267,7 +313,7 @@ SECP256K1_INLINE static int secp256k1_scalar_is_one(const secp256k1_scalar *a) {
static int secp256k1_scalar_is_high(const secp256k1_scalar *a) {
int yes = 0;
int no = 0;
secp256k1_scalar_verify(a);
SECP256K1_SCALAR_VERIFY(a);
no |= (a->d[7] < SECP256K1_N_H_7);
yes |= (a->d[7] > SECP256K1_N_H_7) & ~no;
@@ -291,7 +337,7 @@ static int secp256k1_scalar_cond_negate(secp256k1_scalar *r, int flag) {
uint32_t mask = -vflag;
uint32_t nonzero = 0xFFFFFFFFUL * (secp256k1_scalar_is_zero(r) == 0);
uint64_t t = (uint64_t)(r->d[0] ^ mask) + ((SECP256K1_N_0 + 1) & mask);
secp256k1_scalar_verify(r);
SECP256K1_SCALAR_VERIFY(r);
r->d[0] = t & nonzero; t >>= 32;
t += (uint64_t)(r->d[1] ^ mask) + (SECP256K1_N_1 & mask);
@@ -309,7 +355,7 @@ static int secp256k1_scalar_cond_negate(secp256k1_scalar *r, int flag) {
t += (uint64_t)(r->d[7] ^ mask) + (SECP256K1_N_7 & mask);
r->d[7] = t & nonzero;
secp256k1_scalar_verify(r);
SECP256K1_SCALAR_VERIFY(r);
return 2 * (mask == 0) - 1;
}
@@ -700,33 +746,13 @@ static void secp256k1_scalar_sqr_512(uint32_t *l, const secp256k1_scalar *a) {
static void secp256k1_scalar_mul(secp256k1_scalar *r, const secp256k1_scalar *a, const secp256k1_scalar *b) {
uint32_t l[16];
secp256k1_scalar_verify(a);
secp256k1_scalar_verify(b);
SECP256K1_SCALAR_VERIFY(a);
SECP256K1_SCALAR_VERIFY(b);
secp256k1_scalar_mul_512(l, a, b);
secp256k1_scalar_reduce_512(r, l);
secp256k1_scalar_verify(r);
}
static int secp256k1_scalar_shr_int(secp256k1_scalar *r, int n) {
int ret;
secp256k1_scalar_verify(r);
VERIFY_CHECK(n > 0);
VERIFY_CHECK(n < 16);
ret = r->d[0] & ((1 << n) - 1);
r->d[0] = (r->d[0] >> n) + (r->d[1] << (32 - n));
r->d[1] = (r->d[1] >> n) + (r->d[2] << (32 - n));
r->d[2] = (r->d[2] >> n) + (r->d[3] << (32 - n));
r->d[3] = (r->d[3] >> n) + (r->d[4] << (32 - n));
r->d[4] = (r->d[4] >> n) + (r->d[5] << (32 - n));
r->d[5] = (r->d[5] >> n) + (r->d[6] << (32 - n));
r->d[6] = (r->d[6] >> n) + (r->d[7] << (32 - n));
r->d[7] = (r->d[7] >> n);
secp256k1_scalar_verify(r);
return ret;
SECP256K1_SCALAR_VERIFY(r);
}
static void secp256k1_scalar_sqr(secp256k1_scalar *r, const secp256k1_scalar *a) {
@@ -736,7 +762,7 @@ static void secp256k1_scalar_sqr(secp256k1_scalar *r, const secp256k1_scalar *a)
}
static void secp256k1_scalar_split_128(secp256k1_scalar *r1, secp256k1_scalar *r2, const secp256k1_scalar *k) {
secp256k1_scalar_verify(k);
SECP256K1_SCALAR_VERIFY(k);
r1->d[0] = k->d[0];
r1->d[1] = k->d[1];
@@ -755,13 +781,13 @@ static void secp256k1_scalar_split_128(secp256k1_scalar *r1, secp256k1_scalar *r
r2->d[6] = 0;
r2->d[7] = 0;
secp256k1_scalar_verify(r1);
secp256k1_scalar_verify(r2);
SECP256K1_SCALAR_VERIFY(r1);
SECP256K1_SCALAR_VERIFY(r2);
}
SECP256K1_INLINE static int secp256k1_scalar_eq(const secp256k1_scalar *a, const secp256k1_scalar *b) {
secp256k1_scalar_verify(a);
secp256k1_scalar_verify(b);
SECP256K1_SCALAR_VERIFY(a);
SECP256K1_SCALAR_VERIFY(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;
}
@@ -771,8 +797,8 @@ SECP256K1_INLINE static void secp256k1_scalar_mul_shift_var(secp256k1_scalar *r,
unsigned int shiftlimbs;
unsigned int shiftlow;
unsigned int shifthigh;
secp256k1_scalar_verify(a);
secp256k1_scalar_verify(b);
SECP256K1_SCALAR_VERIFY(a);
SECP256K1_SCALAR_VERIFY(b);
VERIFY_CHECK(shift >= 256);
secp256k1_scalar_mul_512(l, a, b);
@@ -789,13 +815,13 @@ SECP256K1_INLINE static void secp256k1_scalar_mul_shift_var(secp256k1_scalar *r,
r->d[7] = shift < 288 ? (l[7 + shiftlimbs] >> shiftlow) : 0;
secp256k1_scalar_cadd_bit(r, 0, (l[(shift - 1) >> 5] >> ((shift - 1) & 0x1f)) & 1);
secp256k1_scalar_verify(r);
SECP256K1_SCALAR_VERIFY(r);
}
static SECP256K1_INLINE void secp256k1_scalar_cmov(secp256k1_scalar *r, const secp256k1_scalar *a, int flag) {
uint32_t mask0, mask1;
volatile int vflag = flag;
secp256k1_scalar_verify(a);
SECP256K1_SCALAR_VERIFY(a);
SECP256K1_CHECKMEM_CHECK_VERIFY(r->d, sizeof(r->d));
mask0 = vflag + ~((uint32_t)0);
@@ -809,7 +835,7 @@ static SECP256K1_INLINE void secp256k1_scalar_cmov(secp256k1_scalar *r, const se
r->d[6] = (r->d[6] & mask0) | (a->d[6] & mask1);
r->d[7] = (r->d[7] & mask0) | (a->d[7] & mask1);
secp256k1_scalar_verify(r);
SECP256K1_SCALAR_VERIFY(r);
}
static void secp256k1_scalar_from_signed30(secp256k1_scalar *r, const secp256k1_modinv32_signed30 *a) {
@@ -838,14 +864,14 @@ static void secp256k1_scalar_from_signed30(secp256k1_scalar *r, const secp256k1_
r->d[6] = a6 >> 12 | a7 << 18;
r->d[7] = a7 >> 14 | a8 << 16;
secp256k1_scalar_verify(r);
SECP256K1_SCALAR_VERIFY(r);
}
static void secp256k1_scalar_to_signed30(secp256k1_modinv32_signed30 *r, const secp256k1_scalar *a) {
const uint32_t M30 = UINT32_MAX >> 2;
const uint32_t a0 = a->d[0], a1 = a->d[1], a2 = a->d[2], a3 = a->d[3],
a4 = a->d[4], a5 = a->d[5], a6 = a->d[6], a7 = a->d[7];
secp256k1_scalar_verify(a);
SECP256K1_SCALAR_VERIFY(a);
r->v[0] = a0 & M30;
r->v[1] = (a0 >> 30 | a1 << 2) & M30;
@@ -868,16 +894,14 @@ static void secp256k1_scalar_inverse(secp256k1_scalar *r, const secp256k1_scalar
#ifdef VERIFY
int zero_in = secp256k1_scalar_is_zero(x);
#endif
secp256k1_scalar_verify(x);
SECP256K1_SCALAR_VERIFY(x);
secp256k1_scalar_to_signed30(&s, x);
secp256k1_modinv32(&s, &secp256k1_const_modinfo_scalar);
secp256k1_scalar_from_signed30(r, &s);
secp256k1_scalar_verify(r);
#ifdef VERIFY
SECP256K1_SCALAR_VERIFY(r);
VERIFY_CHECK(secp256k1_scalar_is_zero(r) == zero_in);
#endif
}
static void secp256k1_scalar_inverse_var(secp256k1_scalar *r, const secp256k1_scalar *x) {
@@ -885,20 +909,18 @@ static void secp256k1_scalar_inverse_var(secp256k1_scalar *r, const secp256k1_sc
#ifdef VERIFY
int zero_in = secp256k1_scalar_is_zero(x);
#endif
secp256k1_scalar_verify(x);
SECP256K1_SCALAR_VERIFY(x);
secp256k1_scalar_to_signed30(&s, x);
secp256k1_modinv32_var(&s, &secp256k1_const_modinfo_scalar);
secp256k1_scalar_from_signed30(r, &s);
secp256k1_scalar_verify(r);
#ifdef VERIFY
SECP256K1_SCALAR_VERIFY(r);
VERIFY_CHECK(secp256k1_scalar_is_zero(r) == zero_in);
#endif
}
SECP256K1_INLINE static int secp256k1_scalar_is_even(const secp256k1_scalar *a) {
secp256k1_scalar_verify(a);
SECP256K1_SCALAR_VERIFY(a);
return !(a->d[0] & 1);
}