session-android/libaxolotl/jni/ed25519/sign.c
Moxie Marlinspike 2ed8d333d9 Add ed25519
2014-10-20 12:14:18 -07:00

42 lines
817 B
C

#include <string.h>
#include "crypto_sign.h"
#include "crypto_hash_sha512.h"
#include "ge.h"
#include "sc.h"
int crypto_sign(
unsigned char *sm,unsigned long long *smlen,
const unsigned char *m,unsigned long long mlen,
const unsigned char *sk
)
{
unsigned char pk[32];
unsigned char az[64];
unsigned char nonce[64];
unsigned char hram[64];
ge_p3 R;
memmove(pk,sk + 32,32);
crypto_hash_sha512(az,sk,32);
az[0] &= 248;
az[31] &= 63;
az[31] |= 64;
*smlen = mlen + 64;
memmove(sm + 64,m,mlen);
memmove(sm + 32,az + 32,32);
crypto_hash_sha512(nonce,sm + 32,mlen + 32);
memmove(sm + 32,pk,32);
sc_reduce(nonce);
ge_scalarmult_base(&R,nonce);
ge_p3_tobytes(sm,&R);
crypto_hash_sha512(hram,sm,mlen + 64);
sc_reduce(hram);
sc_muladd(sm + 32,hram,az,nonce);
return 0;
}