diff options
Diffstat (limited to 'crypto/secp256k1/libsecp256k1/src/field_5x52_impl.h')
-rw-r--r-- | crypto/secp256k1/libsecp256k1/src/field_5x52_impl.h | 451 |
1 files changed, 0 insertions, 451 deletions
diff --git a/crypto/secp256k1/libsecp256k1/src/field_5x52_impl.h b/crypto/secp256k1/libsecp256k1/src/field_5x52_impl.h deleted file mode 100644 index dd88f38c7..000000000 --- a/crypto/secp256k1/libsecp256k1/src/field_5x52_impl.h +++ /dev/null @@ -1,451 +0,0 @@ -/********************************************************************** - * Copyright (c) 2013, 2014 Pieter Wuille * - * Distributed under the MIT software license, see the accompanying * - * file COPYING or http://www.opensource.org/licenses/mit-license.php.* - **********************************************************************/ - -#ifndef _SECP256K1_FIELD_REPR_IMPL_H_ -#define _SECP256K1_FIELD_REPR_IMPL_H_ - -#if defined HAVE_CONFIG_H -#include "libsecp256k1-config.h" -#endif - -#include "util.h" -#include "num.h" -#include "field.h" - -#if defined(USE_ASM_X86_64) -#include "field_5x52_asm_impl.h" -#else -#include "field_5x52_int128_impl.h" -#endif - -/** Implements arithmetic modulo FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFE FFFFFC2F, - * represented as 5 uint64_t's in base 2^52. The values are allowed to contain >52 each. In particular, - * each FieldElem has a 'magnitude' associated with it. Internally, a magnitude M means each element - * is at most M*(2^53-1), except the most significant one, which is limited to M*(2^49-1). All operations - * accept any input with magnitude at most M, and have different rules for propagating magnitude to their - * output. - */ - -#ifdef VERIFY -static void secp256k1_fe_verify(const secp256k1_fe *a) { - const uint64_t *d = a->n; - int m = a->normalized ? 1 : 2 * a->magnitude, r = 1; - /* secp256k1 'p' value defined in "Standards for Efficient Cryptography" (SEC2) 2.7.1. */ - r &= (d[0] <= 0xFFFFFFFFFFFFFULL * m); - r &= (d[1] <= 0xFFFFFFFFFFFFFULL * m); - r &= (d[2] <= 0xFFFFFFFFFFFFFULL * m); - r &= (d[3] <= 0xFFFFFFFFFFFFFULL * m); - r &= (d[4] <= 0x0FFFFFFFFFFFFULL * m); - r &= (a->magnitude >= 0); - r &= (a->magnitude <= 2048); - if (a->normalized) { - r &= (a->magnitude <= 1); - if (r && (d[4] == 0x0FFFFFFFFFFFFULL) && ((d[3] & d[2] & d[1]) == 0xFFFFFFFFFFFFFULL)) { - r &= (d[0] < 0xFFFFEFFFFFC2FULL); - } - } - VERIFY_CHECK(r == 1); -} -#endif - -static void secp256k1_fe_normalize(secp256k1_fe *r) { - uint64_t t0 = r->n[0], t1 = r->n[1], t2 = r->n[2], t3 = r->n[3], t4 = r->n[4]; - - /* Reduce t4 at the start so there will be at most a single carry from the first pass */ - uint64_t m; - uint64_t x = t4 >> 48; t4 &= 0x0FFFFFFFFFFFFULL; - - /* The first pass ensures the magnitude is 1, ... */ - t0 += x * 0x1000003D1ULL; - t1 += (t0 >> 52); t0 &= 0xFFFFFFFFFFFFFULL; - t2 += (t1 >> 52); t1 &= 0xFFFFFFFFFFFFFULL; m = t1; - t3 += (t2 >> 52); t2 &= 0xFFFFFFFFFFFFFULL; m &= t2; - t4 += (t3 >> 52); t3 &= 0xFFFFFFFFFFFFFULL; m &= t3; - - /* ... except for a possible carry at bit 48 of t4 (i.e. bit 256 of the field element) */ - VERIFY_CHECK(t4 >> 49 == 0); - - /* At most a single final reduction is needed; check if the value is >= the field characteristic */ - x = (t4 >> 48) | ((t4 == 0x0FFFFFFFFFFFFULL) & (m == 0xFFFFFFFFFFFFFULL) - & (t0 >= 0xFFFFEFFFFFC2FULL)); - - /* Apply the final reduction (for constant-time behaviour, we do it always) */ - t0 += x * 0x1000003D1ULL; - t1 += (t0 >> 52); t0 &= 0xFFFFFFFFFFFFFULL; - t2 += (t1 >> 52); t1 &= 0xFFFFFFFFFFFFFULL; - t3 += (t2 >> 52); t2 &= 0xFFFFFFFFFFFFFULL; - t4 += (t3 >> 52); t3 &= 0xFFFFFFFFFFFFFULL; - - /* If t4 didn't carry to bit 48 already, then it should have after any final reduction */ - VERIFY_CHECK(t4 >> 48 == x); - - /* Mask off the possible multiple of 2^256 from the final reduction */ - t4 &= 0x0FFFFFFFFFFFFULL; - - r->n[0] = t0; r->n[1] = t1; r->n[2] = t2; r->n[3] = t3; r->n[4] = t4; - -#ifdef VERIFY - r->magnitude = 1; - r->normalized = 1; - secp256k1_fe_verify(r); -#endif -} - -static void secp256k1_fe_normalize_weak(secp256k1_fe *r) { - uint64_t t0 = r->n[0], t1 = r->n[1], t2 = r->n[2], t3 = r->n[3], t4 = r->n[4]; - - /* Reduce t4 at the start so there will be at most a single carry from the first pass */ - uint64_t x = t4 >> 48; t4 &= 0x0FFFFFFFFFFFFULL; - - /* The first pass ensures the magnitude is 1, ... */ - t0 += x * 0x1000003D1ULL; - t1 += (t0 >> 52); t0 &= 0xFFFFFFFFFFFFFULL; - t2 += (t1 >> 52); t1 &= 0xFFFFFFFFFFFFFULL; - t3 += (t2 >> 52); t2 &= 0xFFFFFFFFFFFFFULL; - t4 += (t3 >> 52); t3 &= 0xFFFFFFFFFFFFFULL; - - /* ... except for a possible carry at bit 48 of t4 (i.e. bit 256 of the field element) */ - VERIFY_CHECK(t4 >> 49 == 0); - - r->n[0] = t0; r->n[1] = t1; r->n[2] = t2; r->n[3] = t3; r->n[4] = t4; - -#ifdef VERIFY - r->magnitude = 1; - secp256k1_fe_verify(r); -#endif -} - -static void secp256k1_fe_normalize_var(secp256k1_fe *r) { - uint64_t t0 = r->n[0], t1 = r->n[1], t2 = r->n[2], t3 = r->n[3], t4 = r->n[4]; - - /* Reduce t4 at the start so there will be at most a single carry from the first pass */ - uint64_t m; - uint64_t x = t4 >> 48; t4 &= 0x0FFFFFFFFFFFFULL; - - /* The first pass ensures the magnitude is 1, ... */ - t0 += x * 0x1000003D1ULL; - t1 += (t0 >> 52); t0 &= 0xFFFFFFFFFFFFFULL; - t2 += (t1 >> 52); t1 &= 0xFFFFFFFFFFFFFULL; m = t1; - t3 += (t2 >> 52); t2 &= 0xFFFFFFFFFFFFFULL; m &= t2; - t4 += (t3 >> 52); t3 &= 0xFFFFFFFFFFFFFULL; m &= t3; - - /* ... except for a possible carry at bit 48 of t4 (i.e. bit 256 of the field element) */ - VERIFY_CHECK(t4 >> 49 == 0); - - /* At most a single final reduction is needed; check if the value is >= the field characteristic */ - x = (t4 >> 48) | ((t4 == 0x0FFFFFFFFFFFFULL) & (m == 0xFFFFFFFFFFFFFULL) - & (t0 >= 0xFFFFEFFFFFC2FULL)); - - if (x) { - t0 += 0x1000003D1ULL; - t1 += (t0 >> 52); t0 &= 0xFFFFFFFFFFFFFULL; - t2 += (t1 >> 52); t1 &= 0xFFFFFFFFFFFFFULL; - t3 += (t2 >> 52); t2 &= 0xFFFFFFFFFFFFFULL; - t4 += (t3 >> 52); t3 &= 0xFFFFFFFFFFFFFULL; - - /* If t4 didn't carry to bit 48 already, then it should have after any final reduction */ - VERIFY_CHECK(t4 >> 48 == x); - - /* Mask off the possible multiple of 2^256 from the final reduction */ - t4 &= 0x0FFFFFFFFFFFFULL; - } - - r->n[0] = t0; r->n[1] = t1; r->n[2] = t2; r->n[3] = t3; r->n[4] = t4; - -#ifdef VERIFY - r->magnitude = 1; - r->normalized = 1; - secp256k1_fe_verify(r); -#endif -} - -static int secp256k1_fe_normalizes_to_zero(secp256k1_fe *r) { - uint64_t t0 = r->n[0], t1 = r->n[1], t2 = r->n[2], t3 = r->n[3], t4 = r->n[4]; - - /* z0 tracks a possible raw value of 0, z1 tracks a possible raw value of P */ - uint64_t z0, z1; - - /* Reduce t4 at the start so there will be at most a single carry from the first pass */ - uint64_t x = t4 >> 48; t4 &= 0x0FFFFFFFFFFFFULL; - - /* The first pass ensures the magnitude is 1, ... */ - t0 += x * 0x1000003D1ULL; - t1 += (t0 >> 52); t0 &= 0xFFFFFFFFFFFFFULL; z0 = t0; z1 = t0 ^ 0x1000003D0ULL; - t2 += (t1 >> 52); t1 &= 0xFFFFFFFFFFFFFULL; z0 |= t1; z1 &= t1; - t3 += (t2 >> 52); t2 &= 0xFFFFFFFFFFFFFULL; z0 |= t2; z1 &= t2; - t4 += (t3 >> 52); t3 &= 0xFFFFFFFFFFFFFULL; z0 |= t3; z1 &= t3; - z0 |= t4; z1 &= t4 ^ 0xF000000000000ULL; - - /* ... except for a possible carry at bit 48 of t4 (i.e. bit 256 of the field element) */ - VERIFY_CHECK(t4 >> 49 == 0); - - return (z0 == 0) | (z1 == 0xFFFFFFFFFFFFFULL); -} - -static int secp256k1_fe_normalizes_to_zero_var(secp256k1_fe *r) { - uint64_t t0, t1, t2, t3, t4; - uint64_t z0, z1; - uint64_t x; - - t0 = r->n[0]; - t4 = r->n[4]; - - /* Reduce t4 at the start so there will be at most a single carry from the first pass */ - x = t4 >> 48; - - /* The first pass ensures the magnitude is 1, ... */ - t0 += x * 0x1000003D1ULL; - - /* z0 tracks a possible raw value of 0, z1 tracks a possible raw value of P */ - z0 = t0 & 0xFFFFFFFFFFFFFULL; - z1 = z0 ^ 0x1000003D0ULL; - - /* Fast return path should catch the majority of cases */ - if ((z0 != 0ULL) & (z1 != 0xFFFFFFFFFFFFFULL)) { - return 0; - } - - t1 = r->n[1]; - t2 = r->n[2]; - t3 = r->n[3]; - - t4 &= 0x0FFFFFFFFFFFFULL; - - t1 += (t0 >> 52); - t2 += (t1 >> 52); t1 &= 0xFFFFFFFFFFFFFULL; z0 |= t1; z1 &= t1; - t3 += (t2 >> 52); t2 &= 0xFFFFFFFFFFFFFULL; z0 |= t2; z1 &= t2; - t4 += (t3 >> 52); t3 &= 0xFFFFFFFFFFFFFULL; z0 |= t3; z1 &= t3; - z0 |= t4; z1 &= t4 ^ 0xF000000000000ULL; - - /* ... except for a possible carry at bit 48 of t4 (i.e. bit 256 of the field element) */ - VERIFY_CHECK(t4 >> 49 == 0); - - return (z0 == 0) | (z1 == 0xFFFFFFFFFFFFFULL); -} - -SECP256K1_INLINE static void secp256k1_fe_set_int(secp256k1_fe *r, int a) { - r->n[0] = a; - r->n[1] = r->n[2] = r->n[3] = r->n[4] = 0; -#ifdef VERIFY - r->magnitude = 1; - r->normalized = 1; - secp256k1_fe_verify(r); -#endif -} - -SECP256K1_INLINE static int secp256k1_fe_is_zero(const secp256k1_fe *a) { - const uint64_t *t = a->n; -#ifdef VERIFY - VERIFY_CHECK(a->normalized); - secp256k1_fe_verify(a); -#endif - return (t[0] | t[1] | t[2] | t[3] | t[4]) == 0; -} - -SECP256K1_INLINE static int secp256k1_fe_is_odd(const secp256k1_fe *a) { -#ifdef VERIFY - VERIFY_CHECK(a->normalized); - secp256k1_fe_verify(a); -#endif - return a->n[0] & 1; -} - -SECP256K1_INLINE static void secp256k1_fe_clear(secp256k1_fe *a) { - int i; -#ifdef VERIFY - a->magnitude = 0; - a->normalized = 1; -#endif - for (i=0; i<5; i++) { - a->n[i] = 0; - } -} - -static int secp256k1_fe_cmp_var(const secp256k1_fe *a, const secp256k1_fe *b) { - int i; -#ifdef VERIFY - VERIFY_CHECK(a->normalized); - VERIFY_CHECK(b->normalized); - secp256k1_fe_verify(a); - secp256k1_fe_verify(b); -#endif - for (i = 4; i >= 0; i--) { - if (a->n[i] > b->n[i]) { - return 1; - } - if (a->n[i] < b->n[i]) { - return -1; - } - } - return 0; -} - -static int secp256k1_fe_set_b32(secp256k1_fe *r, const unsigned char *a) { - int i; - r->n[0] = r->n[1] = r->n[2] = r->n[3] = r->n[4] = 0; - for (i=0; i<32; i++) { - int j; - for (j=0; j<2; j++) { - int limb = (8*i+4*j)/52; - int shift = (8*i+4*j)%52; - r->n[limb] |= (uint64_t)((a[31-i] >> (4*j)) & 0xF) << shift; - } - } - if (r->n[4] == 0x0FFFFFFFFFFFFULL && (r->n[3] & r->n[2] & r->n[1]) == 0xFFFFFFFFFFFFFULL && r->n[0] >= 0xFFFFEFFFFFC2FULL) { - return 0; - } -#ifdef VERIFY - r->magnitude = 1; - r->normalized = 1; - secp256k1_fe_verify(r); -#endif - return 1; -} - -/** Convert a field element to a 32-byte big endian value. Requires the input to be normalized */ -static void secp256k1_fe_get_b32(unsigned char *r, const secp256k1_fe *a) { - int i; -#ifdef VERIFY - VERIFY_CHECK(a->normalized); - secp256k1_fe_verify(a); -#endif - for (i=0; i<32; i++) { - int j; - int c = 0; - for (j=0; j<2; j++) { - int limb = (8*i+4*j)/52; - int shift = (8*i+4*j)%52; - c |= ((a->n[limb] >> shift) & 0xF) << (4 * j); - } - r[31-i] = c; - } -} - -SECP256K1_INLINE static void secp256k1_fe_negate(secp256k1_fe *r, const secp256k1_fe *a, int m) { -#ifdef VERIFY - VERIFY_CHECK(a->magnitude <= m); - secp256k1_fe_verify(a); -#endif - r->n[0] = 0xFFFFEFFFFFC2FULL * 2 * (m + 1) - a->n[0]; - r->n[1] = 0xFFFFFFFFFFFFFULL * 2 * (m + 1) - a->n[1]; - r->n[2] = 0xFFFFFFFFFFFFFULL * 2 * (m + 1) - a->n[2]; - r->n[3] = 0xFFFFFFFFFFFFFULL * 2 * (m + 1) - a->n[3]; - r->n[4] = 0x0FFFFFFFFFFFFULL * 2 * (m + 1) - a->n[4]; -#ifdef VERIFY - r->magnitude = m + 1; - r->normalized = 0; - secp256k1_fe_verify(r); -#endif -} - -SECP256K1_INLINE static void secp256k1_fe_mul_int(secp256k1_fe *r, int a) { - r->n[0] *= a; - r->n[1] *= a; - r->n[2] *= a; - r->n[3] *= a; - r->n[4] *= a; -#ifdef VERIFY - r->magnitude *= a; - r->normalized = 0; - secp256k1_fe_verify(r); -#endif -} - -SECP256K1_INLINE static void secp256k1_fe_add(secp256k1_fe *r, const secp256k1_fe *a) { -#ifdef VERIFY - secp256k1_fe_verify(a); -#endif - r->n[0] += a->n[0]; - r->n[1] += a->n[1]; - r->n[2] += a->n[2]; - r->n[3] += a->n[3]; - r->n[4] += a->n[4]; -#ifdef VERIFY - r->magnitude += a->magnitude; - r->normalized = 0; - secp256k1_fe_verify(r); -#endif -} - -static void secp256k1_fe_mul(secp256k1_fe *r, const secp256k1_fe *a, const secp256k1_fe * SECP256K1_RESTRICT b) { -#ifdef VERIFY - VERIFY_CHECK(a->magnitude <= 8); - VERIFY_CHECK(b->magnitude <= 8); - secp256k1_fe_verify(a); - secp256k1_fe_verify(b); - VERIFY_CHECK(r != b); -#endif - secp256k1_fe_mul_inner(r->n, a->n, b->n); -#ifdef VERIFY - r->magnitude = 1; - r->normalized = 0; - secp256k1_fe_verify(r); -#endif -} - -static void secp256k1_fe_sqr(secp256k1_fe *r, const secp256k1_fe *a) { -#ifdef VERIFY - VERIFY_CHECK(a->magnitude <= 8); - secp256k1_fe_verify(a); -#endif - secp256k1_fe_sqr_inner(r->n, a->n); -#ifdef VERIFY - r->magnitude = 1; - r->normalized = 0; - secp256k1_fe_verify(r); -#endif -} - -static SECP256K1_INLINE void secp256k1_fe_cmov(secp256k1_fe *r, const secp256k1_fe *a, int flag) { - uint64_t mask0, mask1; - mask0 = flag + ~((uint64_t)0); - mask1 = ~mask0; - r->n[0] = (r->n[0] & mask0) | (a->n[0] & mask1); - r->n[1] = (r->n[1] & mask0) | (a->n[1] & mask1); - r->n[2] = (r->n[2] & mask0) | (a->n[2] & mask1); - r->n[3] = (r->n[3] & mask0) | (a->n[3] & mask1); - r->n[4] = (r->n[4] & mask0) | (a->n[4] & mask1); -#ifdef VERIFY - if (a->magnitude > r->magnitude) { - r->magnitude = a->magnitude; - } - r->normalized &= a->normalized; -#endif -} - -static SECP256K1_INLINE void secp256k1_fe_storage_cmov(secp256k1_fe_storage *r, const secp256k1_fe_storage *a, int flag) { - uint64_t mask0, mask1; - mask0 = flag + ~((uint64_t)0); - mask1 = ~mask0; - r->n[0] = (r->n[0] & mask0) | (a->n[0] & mask1); - r->n[1] = (r->n[1] & mask0) | (a->n[1] & mask1); - r->n[2] = (r->n[2] & mask0) | (a->n[2] & mask1); - r->n[3] = (r->n[3] & mask0) | (a->n[3] & mask1); -} - -static void secp256k1_fe_to_storage(secp256k1_fe_storage *r, const secp256k1_fe *a) { -#ifdef VERIFY - VERIFY_CHECK(a->normalized); -#endif - r->n[0] = a->n[0] | a->n[1] << 52; - r->n[1] = a->n[1] >> 12 | a->n[2] << 40; - r->n[2] = a->n[2] >> 24 | a->n[3] << 28; - r->n[3] = a->n[3] >> 36 | a->n[4] << 16; -} - -static SECP256K1_INLINE void secp256k1_fe_from_storage(secp256k1_fe *r, const secp256k1_fe_storage *a) { - r->n[0] = a->n[0] & 0xFFFFFFFFFFFFFULL; - r->n[1] = a->n[0] >> 52 | ((a->n[1] << 12) & 0xFFFFFFFFFFFFFULL); - r->n[2] = a->n[1] >> 40 | ((a->n[2] << 24) & 0xFFFFFFFFFFFFFULL); - r->n[3] = a->n[2] >> 28 | ((a->n[3] << 36) & 0xFFFFFFFFFFFFFULL); - r->n[4] = a->n[3] >> 16; -#ifdef VERIFY - r->magnitude = 1; - r->normalized = 1; -#endif -} - -#endif |