//CONVERT #include <string.h>
//CONVERT #include "crypto_sign.h"
//CONVERT #include "crypto_hash_sha512.h"
//CONVERT #include "ge.h"
//CONVERT #include "sc.h"
//CONVERT #include "zeroize.h"
/* NEW: Compare to pristine crypto_sign()
* Uses explicit private key for nonce derivation and as scalar,
* instead of deriving both from a master key.
*/
public static int crypto_sign_modified(
ISha512 sha512provider,
byte[] sm,
byte[] m, long mlen,
byte[] sk, byte[] pk,
byte[] random
)
{
byte[] nonce = new byte[64];
byte[] hram = new byte[64];
Ge_p3 R = new Ge_p3();
int count = 0;
Array.Copy(m, 0, sm, 64, (int)mlen);
Array.Copy(sk, 0, sm, 32, 32);
/* NEW : add prefix to separate hash uses - see .h */
sm[0] = (byte)0xFE;
for (count = 1; count < 32; count++)
{
sm[count] = (byte)0xFF;
}
/* NEW: add suffix of random data */
Array.Copy(random, 0, sm, (int)(mlen + 64), 64);
sha512provider.calculateDigest(nonce, sm, mlen + 128);
Array.Copy(pk, 0, sm, 32, 32);
Sc_reduce.sc_reduce(nonce);
Ge_scalarmult_base.ge_scalarmult_base(R, nonce);
Ge_p3_tobytes.ge_p3_tobytes(sm, R);
sha512provider.calculateDigest(hram, sm, mlen + 64);
Sc_reduce.sc_reduce(hram);
byte[] S = new byte[32];
Sc_muladd.sc_muladd(S, hram, sk, nonce); /* NEW: Use privkey directly */
Array.Copy(S, 0, sm, 32, 32);
/* Erase any traces of private scalar or
* nonce left in the stack from sc_muladd */
//zeroize_stack();
Zeroize.zeroize(nonce, 64);
return(0);
}
public static int uxed25519_sign(ISha512 sha512provider,
byte[] signature_out,
byte[] curve25519_privkey,
byte[] msg, int msg_len,
byte[] random)
{
// just return -1 as this shouldn't be used
return(-1);
byte[] a = new byte[32];
byte[] aneg = new byte[32];
byte[] A = new byte[32];
Ge_p3 Bu = new Ge_p3();
Ge_p3 ed_pubkey_point = new Ge_p3();
byte[] sigbuf = new byte[crypto_additions.MAX_MSG_LEN + 160]; /* working buffer */
byte sign_bit = 0;
if (msg_len > crypto_additions.MAX_MSG_LEN)
{
//memset(signature_out, 0, 96);
return(-1);
}
/* Convert the Curve25519 privkey to an Ed25519 public key */
Ge_scalarmult_base.ge_scalarmult_base(ed_pubkey_point, curve25519_privkey);
Ge_p3_tobytes.ge_p3_tobytes(A, ed_pubkey_point);
/* Force Edwards sign bit to zero */
sign_bit = (byte)((A[31] & 0x80) >> 7);
Array.Copy(curve25519_privkey, 0, a, 0, 32);
Sc_neg.sc_neg(aneg, a);
Sc_cmov.sc_cmov(a, aneg, sign_bit);
A[31] &= 0x7F;
//Elligator.calculate_Bv_and_V(sha512provider, Bu, signature_out, sigbuf, a, msg, msg_len);
/* Perform an Ed25519 signature with explicit private key */
usign_modified.crypto_usign_modified(sha512provider, sigbuf, msg, msg_len, a, A, random, Bu, signature_out /*U*/);
Array.Copy(sigbuf, 0, signature_out, 32, 64);
Zeroize.zeroize(a, 32);
return(0);
}
public static int xed25519_sign(ISha512 sha512provider,
byte[] signature_out,
byte[] curve25519_privkey,
byte[] msg, int msg_len,
byte[] random)
{
byte[] a = new byte[32];
byte[] A = new byte[32];
byte[] aneg = new byte[32];
Ge_p3 ed_pubkey_point = new Ge_p3();
// see link below
byte[] sigbuf = new byte[msg_len + 128]; /* working buffer */
byte sign_bit = 0;
// this should be different but whatever
// https://github.com/WhisperSystems/curve25519-java/commit/2f388f601afdac6a78a19ced2f0629da1ff9800f#diff-6e488e4e28814b3fa524b6781fcaf912R19
//if (msg_len > crypto_additions.MAX_MSG_LEN)
//{
// //memset(signature_out, 0, 64);
// return -1;
//}
/* Convert the Curve25519 privkey to an Ed25519 public key */
Ge_scalarmult_base.ge_scalarmult_base(ed_pubkey_point, curve25519_privkey);
Ge_p3_tobytes.ge_p3_tobytes(A, ed_pubkey_point);
/* Force Edwards sign bit to zero */
sign_bit = (byte)((A[31] & 0x80) >> 7);
Array.Copy(curve25519_privkey, 0, a, 0, 32);
Sc_neg.sc_neg(aneg, a);
Sc_cmov.sc_cmov(a, aneg, sign_bit);
A[31] &= 0x7F;
/* Perform an Ed25519 signature with explicit private key */
sign_modified.crypto_sign_modified(sha512provider, sigbuf, msg, msg_len, a, A, random);
Array.Copy(sigbuf, 0, signature_out, 0, 64);
Zeroize.zeroize(a, 32);
Zeroize.zeroize(aneg, 32);
return(0);
}
public static int crypto_vsign_modified(ISha512 sha512provider,
byte[] sm,
byte[] M, int Mlen,
byte[] a,
byte[] A,
byte[] random,
Ge_p3 Bv,
byte[] V)
{
byte[] r = new byte[64];
byte[] h = new byte[64];
Ge_p3 R = new Ge_p3();
Ge_p3 Rv = new Ge_p3();
int count = 0;
/* r = SHA512(label(3) || a || V || random(64)) */
sm[0] = 0xFC;
for (count = 1; count < 32; count++)
{
sm[count] = 0xFF;
}
Array.Copy(a, 0, sm, 32, 32); /* Use privkey directly for nonce derivation */
Array.Copy(V, 0, sm, 64, 32);
Array.Copy(random, 0, sm, 96, 64); /* Add suffix of random data */
sha512provider.calculateDigest(r, sm, 160);
Sc_reduce.sc_reduce(r);
Ge_scalarmult_base.ge_scalarmult_base(R, r);
Ge_scalarmult.ge_scalarmult(Rv, r, Bv);
/* h = SHA512(label(4) || A || V || R || Rv || M) */
sm[0] = 0xFB;
Array.Copy(A, 0, sm, 32, 32);
Array.Copy(V, 0, sm, 64, 32);
byte[] R1 = new byte[32];
Array.Copy(sm, 96, R1, 0, 32);
Ge_p3_tobytes.ge_p3_tobytes(R1, R);
Array.Copy(R1, 0, sm, 96, 32);
byte[] R2 = new byte[32];
Array.Copy(sm, 128, R2, 0, 32);
Ge_p3_tobytes.ge_p3_tobytes(R2, Rv);
Array.Copy(R2, 0, sm, 128, 32);
Array.Copy(M, 0, sm, 160, Mlen);
sha512provider.calculateDigest(h, sm, Mlen + 160);
Sc_reduce.sc_reduce(h);
Array.Copy(h, 0, sm, 0, 32);
byte[] S = new byte[32];
Array.Copy(sm, 32, S, 0, 32);
Sc_muladd.sc_muladd(S, h, a, r);
Array.Copy(S, 0, sm, 32, 32);
/* Erase any traces of private scalar or
* nonce left in stack from sc_muladd. */
//zeroize_stack();
Zeroize.zeroize(r, 64);
return(0);
}
