diff options
Diffstat (limited to 'src/ec25519_secret.c')
| -rw-r--r-- | src/ec25519_secret.c | 28 |
1 files changed, 25 insertions, 3 deletions
diff --git a/src/ec25519_secret.c b/src/ec25519_secret.c index 0a58629..b79b46c 100644 --- a/src/ec25519_secret.c +++ b/src/ec25519_secret.c @@ -56,7 +56,20 @@ static void select(unsigned char out[32], const unsigned char r[32], const unsig } } -void ecc_25519_add_secret(ecc_secret_key_256 *out, const ecc_secret_key_256 *in1, const ecc_secret_key_256 *in2) { +int ecc_25519_secret_is_zero(const ecc_secret_key_256 *in) { + int i; + ecc_secret_key_256 r; + unsigned int bits; + + ecc_25519_secret_reduce(&r, in); + + for (i = 0; i < 32; i++) + bits |= r.s[i]; + + return (((bits-1)>>8) & 1); +} + +void ecc_25519_secret_add(ecc_secret_key_256 *out, const ecc_secret_key_256 *in1, const ecc_secret_key_256 *in2) { unsigned int j; int u1, u2, u3; unsigned char out1[32], out2[32], out3[32]; @@ -81,7 +94,7 @@ void ecc_25519_add_secret(ecc_secret_key_256 *out, const ecc_secret_key_256 *in1 select(out->s, out->s, out3, ((u1 >> 8) & (u2 >> 8)) & 1); } -void ecc_25519_sub_secret(ecc_secret_key_256 *out, const ecc_secret_key_256 *in1, const ecc_secret_key_256 *in2) { +void ecc_25519_secret_sub(ecc_secret_key_256 *out, const ecc_secret_key_256 *in1, const ecc_secret_key_256 *in2) { unsigned int j; int u1, u2, u3; unsigned char out1[32], out2[32], out3[32]; @@ -128,6 +141,15 @@ static void reduce(unsigned char a[32]) { select(a, out1, out2, IS_NEGATIVE(u1)); } +void ecc_25519_secret_reduce(ecc_secret_key_256 *out, const ecc_secret_key_256 *in) { + int i; + + for (i = 0; i < 32; i++) + out->s[i] = in->s[i]; + + reduce(out->s); +} + /* Montgomery modular multiplication algorithm */ static void montgomery(unsigned char out[32], const unsigned char a[32], const unsigned char b[32]) { unsigned int a_i; @@ -157,7 +179,7 @@ static void montgomery(unsigned char out[32], const unsigned char a[32], const u } -void ecc_25519_mult_secret(ecc_secret_key_256 *out, const ecc_secret_key_256 *in1, const ecc_secret_key_256 *in2) { +void ecc_25519_secret_mult(ecc_secret_key_256 *out, const ecc_secret_key_256 *in1, const ecc_secret_key_256 *in2) { /* 2^512 mod p */ static const unsigned char C[32] = { 0x01, 0x0f, 0x9c, 0x44, 0xe3, 0x11, 0x06, 0xa4, |