diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/ec25519.c | 24 |
1 files changed, 20 insertions, 4 deletions
diff --git a/src/ec25519.c b/src/ec25519.c index 25ed1f6..effbfc6 100644 --- a/src/ec25519.c +++ b/src/ec25519.c @@ -25,7 +25,7 @@ */ /* - EC group operations for Twisted Edwards Curve ax^2 + y^2 + 1 + dx^2y^2 with + EC group operations for Twisted Edwards Curve ax^2 + y^2 = 1 + dx^2y^2 with a = 486664 d = 486660 on prime field p = 2^255 - 19. @@ -340,7 +340,7 @@ static void recip(unsigned int out[32], const unsigned int z[32]) { /* 2^255 - 21 */ mult(out, t1, z11); } -void ec_25519_inflate(ec_25519_work *out, const ec_public_key_256 *in) { +void ec_25519_load(ec_25519_work *out, const ec_public_key_256 *in) { int i; unsigned int X2[32], d_X2[32] = {0x04, 0x6d, 0x07} /* 486660 */, a_X2[32] = {0x08, 0x6d, 0x07} /* 486664 */, _1_a_X2[32], d_X2_a_X2[32], Y[32], Yt[32]; @@ -359,10 +359,10 @@ void ec_25519_inflate(ec_25519_work *out, const ec_public_key_256 *in) { square_root(Y, d_X2_a_X2); sub(Yt, zero, Y); - select(out->Y, Y, Yt, in->p[31] >> 7); + select(out->Y, Y, Yt, (in->p[31] >> 7) ^ (Y[0] & 1)); } -void ec_25519_deflate(ec_public_key_256 *out, ec_25519_work *in) { +void ec_25519_store(ec_public_key_256 *out, const ec_25519_work *in) { unsigned int x[32], y[32], z[32]; int i; @@ -454,3 +454,19 @@ void ec_25519_scalarmult(ec_25519_work *out, const ec_secret_key_256 *n, const e out->Z[i] = cur.Z[i]; } } + +static const ec_25519_work default_base = { + {0x51, 0x89, 0xfa, 0x46, 0xa0, 0xc0, 0x8b, 0x3d, + 0x30, 0x60, 0xf1, 0x7d, 0x2a, 0xec, 0xcd, 0xf3, + 0x24, 0x50, 0x96, 0x62, 0x21, 0xfc, 0xe6, 0x18, + 0x14, 0xd6, 0x11, 0xf8, 0x11, 0x91, 0xa1, 0x03}, + {0xf3, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, + 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, + 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, + 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x5f}, + {1} +}; + +void ec_25519_scalarmult_base(ec_25519_work *out, const ec_secret_key_256 *n) { + ec_25519_scalarmult(out, n, &default_base); +} |