diff options
Diffstat (limited to 'src/ext/ed25519/ref10/fe_frombytes.c')
-rw-r--r-- | src/ext/ed25519/ref10/fe_frombytes.c | 73 |
1 files changed, 73 insertions, 0 deletions
diff --git a/src/ext/ed25519/ref10/fe_frombytes.c b/src/ext/ed25519/ref10/fe_frombytes.c new file mode 100644 index 0000000000..98b8e5f7c1 --- /dev/null +++ b/src/ext/ed25519/ref10/fe_frombytes.c @@ -0,0 +1,73 @@ +#include "fe.h" +#include "crypto_int64.h" +#include "crypto_uint64.h" + +static crypto_uint64 load_3(const unsigned char *in) +{ + crypto_uint64 result; + result = (crypto_uint64) in[0]; + result |= ((crypto_uint64) in[1]) << 8; + result |= ((crypto_uint64) in[2]) << 16; + return result; +} + +static crypto_uint64 load_4(const unsigned char *in) +{ + crypto_uint64 result; + result = (crypto_uint64) in[0]; + result |= ((crypto_uint64) in[1]) << 8; + result |= ((crypto_uint64) in[2]) << 16; + result |= ((crypto_uint64) in[3]) << 24; + return result; +} + +/* +Ignores top bit of h. +*/ + +void fe_frombytes(fe h,const unsigned char *s) +{ + crypto_int64 h0 = load_4(s); + crypto_int64 h1 = load_3(s + 4) << 6; + crypto_int64 h2 = load_3(s + 7) << 5; + crypto_int64 h3 = load_3(s + 10) << 3; + crypto_int64 h4 = load_3(s + 13) << 2; + crypto_int64 h5 = load_4(s + 16); + crypto_int64 h6 = load_3(s + 20) << 7; + crypto_int64 h7 = load_3(s + 23) << 5; + crypto_int64 h8 = load_3(s + 26) << 4; + crypto_int64 h9 = (load_3(s + 29) & 8388607) << 2; + crypto_int64 carry0; + crypto_int64 carry1; + crypto_int64 carry2; + crypto_int64 carry3; + crypto_int64 carry4; + crypto_int64 carry5; + crypto_int64 carry6; + crypto_int64 carry7; + crypto_int64 carry8; + crypto_int64 carry9; + + carry9 = (h9 + (crypto_int64) (1<<24)) >> 25; h0 += carry9 * 19; h9 -= SHL64(carry9,25); + carry1 = (h1 + (crypto_int64) (1<<24)) >> 25; h2 += carry1; h1 -= SHL64(carry1,25); + carry3 = (h3 + (crypto_int64) (1<<24)) >> 25; h4 += carry3; h3 -= SHL64(carry3,25); + carry5 = (h5 + (crypto_int64) (1<<24)) >> 25; h6 += carry5; h5 -= SHL64(carry5,25); + carry7 = (h7 + (crypto_int64) (1<<24)) >> 25; h8 += carry7; h7 -= SHL64(carry7,25); + + carry0 = (h0 + (crypto_int64) (1<<25)) >> 26; h1 += carry0; h0 -= SHL64(carry0,26); + carry2 = (h2 + (crypto_int64) (1<<25)) >> 26; h3 += carry2; h2 -= SHL64(carry2,26); + carry4 = (h4 + (crypto_int64) (1<<25)) >> 26; h5 += carry4; h4 -= SHL64(carry4,26); + carry6 = (h6 + (crypto_int64) (1<<25)) >> 26; h7 += carry6; h6 -= SHL64(carry6,26); + carry8 = (h8 + (crypto_int64) (1<<25)) >> 26; h9 += carry8; h8 -= SHL64(carry8,26); + + h[0] = (crypto_int32) h0; + h[1] = (crypto_int32) h1; + h[2] = (crypto_int32) h2; + h[3] = (crypto_int32) h3; + h[4] = (crypto_int32) h4; + h[5] = (crypto_int32) h5; + h[6] = (crypto_int32) h6; + h[7] = (crypto_int32) h7; + h[8] = (crypto_int32) h8; + h[9] = (crypto_int32) h9; +} |