ed25519/sign.c
2013-01-11 21:45:11 +01:00

40 lines
854 B
C

#include "ed25519.h"
#include "sha512.h"
#include "ge.h"
#include "sc.h"
int ed25519_sign(unsigned char *signature, const unsigned char *message, unsigned int message_len, const unsigned char *sign_key)
{
unsigned char az[64];
unsigned char r[64];
unsigned char hram[64];
ge_p3 R;
sha512_ctx hash;
sha512(sign_key, 32, az);
az[0] &= 248;
az[31] &= 63;
az[31] |= 64;
sha512_init(&hash);
sha512_update(&hash, az + 32, 32);
sha512_update(&hash, message, message_len);
sha512_final(&hash, r);
sc_reduce(r);
ge_scalarmult_base(&R, r);
ge_p3_tobytes(signature, &R);
sha512_init(&hash);
sha512_update(&hash, signature, 32);
sha512_update(&hash, sign_key + 32, 32);
sha512_update(&hash, message, message_len);
sha512_final(&hash, hram);
sc_reduce(hram);
sc_muladd(signature + 32, hram, az, r);
return 0;
}