-rw-r--r-- 1930 lib25519-20220426/crypto_dh/x25519/sandy2x/fe_frombytes.c raw
/* This file is basically ref10/fe_frombytes.h. */ #include "fe.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; } void fe_frombytes(fe h,const unsigned char *s) { crypto_uint64 h0 = load_4(s); crypto_uint64 h1 = load_3(s + 4) << 6; crypto_uint64 h2 = load_3(s + 7) << 5; crypto_uint64 h3 = load_3(s + 10) << 3; crypto_uint64 h4 = load_3(s + 13) << 2; crypto_uint64 h5 = load_4(s + 16); crypto_uint64 h6 = load_3(s + 20) << 7; crypto_uint64 h7 = load_3(s + 23) << 5; crypto_uint64 h8 = load_3(s + 26) << 4; crypto_uint64 h9 = load_3(s + 29) << 2; crypto_uint64 carry0; crypto_uint64 carry1; crypto_uint64 carry2; crypto_uint64 carry3; crypto_uint64 carry4; crypto_uint64 carry5; crypto_uint64 carry6; crypto_uint64 carry7; crypto_uint64 carry8; crypto_uint64 carry9; carry9 = h9 >> 25; h0 += carry9 * 19; h9 &= 0x1FFFFFF; carry1 = h1 >> 25; h2 += carry1; h1 &= 0x1FFFFFF; carry3 = h3 >> 25; h4 += carry3; h3 &= 0x1FFFFFF; carry5 = h5 >> 25; h6 += carry5; h5 &= 0x1FFFFFF; carry7 = h7 >> 25; h8 += carry7; h7 &= 0x1FFFFFF; carry0 = h0 >> 26; h1 += carry0; h0 &= 0x3FFFFFF; carry2 = h2 >> 26; h3 += carry2; h2 &= 0x3FFFFFF; carry4 = h4 >> 26; h5 += carry4; h4 &= 0x3FFFFFF; carry6 = h6 >> 26; h7 += carry6; h6 &= 0x3FFFFFF; carry8 = h8 >> 26; h9 += carry8; h8 &= 0x3FFFFFF; h[0] = h0; h[1] = h1; h[2] = h2; h[3] = h3; h[4] = h4; h[5] = h5; h[6] = h6; h[7] = h7; h[8] = h8; h[9] = h9; }