ed25519/sign.c
Orson Peters 7da894b006 changes
2013-01-10 21:24:49 +01:00

39 lines
761 B
C

#include "ed25519.h"
#include "sha512.h"
#include "ge.h"
#include "sc.h"
int ed25519_sign(
unsigned char *sm,unsigned long long *smlen,
const unsigned char *m,unsigned long long mlen,
const unsigned char *sk
)
{
unsigned char az[64];
unsigned char r[64];
unsigned char hram[64];
ge_p3 R;
unsigned long long i;
sha512(az,sk,32);
az[0] &= 248;
az[31] &= 63;
az[31] |= 64;
*smlen = mlen + 64;
for (i = 0;i < mlen;++i) sm[64 + i] = m[i];
for (i = 0;i < 32;++i) sm[32 + i] = az[32 + i];
sha512(r,sm + 32,mlen + 32);
for (i = 0;i < 32;++i) sm[32 + i] = sk[32 + i];
sc_reduce(r);
ge_scalarmult_base(&R,r);
ge_p3_tobytes(sm,&R);
sha512(hram,sm,mlen + 64);
sc_reduce(hram);
sc_muladd(sm + 32,hram,az,r);
return 0;
}