i2pd/core/crypto/ed25519/open.cpp
2015-08-29 23:21:32 +02:00

40 lines
835 B
C++

#include <string.h>
#include "crypto_sign.h"
#include "crypto_hash_sha512.h"
#include "crypto_verify_32.h"
#include "ge.h"
#include "sc.h"
int crypto_sign_open(
const unsigned char* sig,
const unsigned char* m, unsigned long long mlen,
const unsigned char* pk
)
{
unsigned char pkcopy[32];
unsigned char rcopy[32];
unsigned char scopy[32];
unsigned char h[64];
unsigned char rcheck[32];
ge_p3 A;
ge_p2 R;
if (sig[63] & 224) goto badsig;
if (ge_frombytes_negate_vartime(&A,pk) != 0) goto badsig;
memmove(pkcopy,pk,32);
memmove(rcopy, sig, 32);
memmove(scopy, sig + 32,32);
crypto_hash_sha512_3(h, rcopy, 32, pkcopy, 32, m, mlen);
sc_reduce(h);
ge_double_scalarmult_vartime(&R,h,&A,scopy);
ge_tobytes(rcheck,&R);
if (crypto_verify_32(rcheck,rcopy) == 0)
return 0;
badsig:
return -1;
}