public static void crypto_sign_keypair(byte[] pk, int pkoffset, byte[] sk, int skoffset, byte[] seed, int seedoffset)
{
GroupElementP3 A;
int i;
Array.Copy(seed, seedoffset, sk, skoffset, 32);
byte[] h = Sha512.Hash(sk, skoffset, 32);//ToDo: Remove alloc
ScalarOperations.sc_clamp(h, 0);
GroupOperations.ge_scalarmult_base(out A, h, 0);
GroupOperations.ge_p3_tobytes(pk, pkoffset, ref A);
for (i = 0; i < 32; ++i)
{
sk[skoffset + 32 + i] = pk[pkoffset + i];
}
CryptoBytes.Wipe(h);
}
// Original crypto_sign_open, for reference only
/*public static int crypto_sign_open(
* byte[] m, out int mlen,
* byte[] sm, int smlen,
* byte[] pk)
* {
* byte[] h = new byte[64];
* byte[] checkr = new byte[32];
* GroupElementP3 A;
* GroupElementP2 R;
* int i;
*
* mlen = -1;
* if (smlen < 64) return -1;
* if ((sm[63] & 224) != 0) return -1;
* if (GroupOperations.ge_frombytes_negate_vartime(out A, pk, 0) != 0) return -1;
*
* for (i = 0; i < smlen; ++i) m[i] = sm[i];
* for (i = 0; i < 32; ++i) m[32 + i] = pk[i];
* Sha512BclWrapper.crypto_hash_sha512(h, m, 0, smlen);
* ScalarOperations.sc_reduce(h);
*
* var sm32 = new byte[32];
* Array.Copy(sm, 32, sm32, 0, 32);
* GroupOperations.ge_double_scalarmult_vartime(out R, h, ref A, sm32);
* GroupOperations.ge_tobytes(checkr, 0, ref R);
* if (Helpers.crypto_verify_32(checkr, sm) != 0)
* {
* for (i = 0; i < smlen; ++i)
* m[i] = 0;
* return -1;
* }
*
* for (i = 0; i < smlen - 64; ++i)
* m[i] = sm[64 + i];
* for (i = smlen - 64; i < smlen; ++i)
* m[i] = 0;
* mlen = smlen - 64;
* return 0;
* }*/
public static bool crypto_sign_verify(
byte[] sig, int sigoffset,
byte[] m, int moffset, int mlen,
byte[] pk, int pkoffset)
{
byte[] h;
byte[] checkr = new byte[32];
GroupElementP3 A;
GroupElementP2 R;
if ((sig[sigoffset + 63] & 224) != 0)
{
return(false);
}
if (GroupOperations.ge_frombytes_negate_vartime(out A, pk, pkoffset) != 0)
{
return(false);
}
var hasher = new Sha512();
hasher.Update(sig, sigoffset, 32);
hasher.Update(pk, pkoffset, 32);
hasher.Update(m, moffset, mlen);
h = hasher.Finalize();
ScalarOperations.sc_reduce(h);
var sm32 = new byte[32];//todo: remove allocation
Array.Copy(sig, sigoffset + 32, sm32, 0, 32);
GroupOperations.ge_double_scalarmult_vartime(out R, h, ref A, sm32);
GroupOperations.ge_tobytes(checkr, 0, ref R);
var result = CryptoBytes.ConstantTimeEquals(checkr, 0, sig, sigoffset, 32);
CryptoBytes.Wipe(h);
CryptoBytes.Wipe(checkr);
return(result);
}
public static void crypto_sign(
byte[] sig, int sigoffset,
byte[] m, int moffset, int mlen,
byte[] sk, int skoffset)
{
byte[] az, r, hram;
GroupElementP3 R;
var hasher = new Sha512();
{
hasher.Update(sk, skoffset, 32);
az = hasher.Finalize();
ScalarOperations.sc_clamp(az, 0);
hasher.Init();
hasher.Update(az, 32, 32);
hasher.Update(m, moffset, mlen);
r = hasher.Finalize();
ScalarOperations.sc_reduce(r);
GroupOperations.ge_scalarmult_base(out R, r, 0);
GroupOperations.ge_p3_tobytes(sig, sigoffset, ref R);
hasher.Init();
hasher.Update(sig, sigoffset, 32);
hasher.Update(sk, skoffset + 32, 32);
hasher.Update(m, moffset, mlen);
hram = hasher.Finalize();
ScalarOperations.sc_reduce(hram);
var s = new byte[32]; //todo: remove allocation
Array.Copy(sig, sigoffset + 32, s, 0, 32);
ScalarOperations.sc_muladd(s, hram, az, r);
Array.Copy(s, 0, sig, sigoffset + 32, 32);
CryptoBytes.Wipe(s);
}
}
internal static void scalarmult(
out FieldElement q,
byte[] n, int noffset,
ref FieldElement p)
{
byte[] e = new byte[32]; //ToDo: remove allocation
FieldElement x1, x2, x3;
FieldElement z2, z3;
FieldElement tmp0, tmp1;
for (int i = 0; i < 32; ++i)
{
e[i] = n[noffset + i];
}
ScalarOperations.sc_clamp(e, 0);
x1 = p;
FieldOperations.fe_1(out x2);
FieldOperations.fe_0(out z2);
x3 = x1;
FieldOperations.fe_1(out z3);
uint swap = 0;
for (int pos = 254; pos >= 0; --pos)
{
uint b = (uint)(e[pos / 8] >> (pos & 7));
b &= 1;
swap ^= b;
FieldOperations.fe_cswap(ref x2, ref x3, swap);
FieldOperations.fe_cswap(ref z2, ref z3, swap);
swap = b;
/* qhasm: enter ladder */
/* qhasm: D = X3-Z3 */
/* asm 1: fe_sub(>D=fe#5,<X3=fe#3,<Z3=fe#4); */
/* asm 2: fe_sub(>D=tmp0,<X3=x3,<Z3=z3); */
FieldOperations.fe_sub(out tmp0, ref x3, ref z3);
/* qhasm: B = X2-Z2 */
/* asm 1: fe_sub(>B=fe#6,<X2=fe#1,<Z2=fe#2); */
/* asm 2: fe_sub(>B=tmp1,<X2=x2,<Z2=z2); */
FieldOperations.fe_sub(out tmp1, ref x2, ref z2);
/* qhasm: A = X2+Z2 */
/* asm 1: fe_add(>A=fe#1,<X2=fe#1,<Z2=fe#2); */
/* asm 2: fe_add(>A=x2,<X2=x2,<Z2=z2); */
FieldOperations.fe_add(out x2, ref x2, ref z2);
/* qhasm: C = X3+Z3 */
/* asm 1: fe_add(>C=fe#2,<X3=fe#3,<Z3=fe#4); */
/* asm 2: fe_add(>C=z2,<X3=x3,<Z3=z3); */
FieldOperations.fe_add(out z2, ref x3, ref z3);
/* qhasm: DA = D*A */
/* asm 1: fe_mul(>DA=fe#4,<D=fe#5,<A=fe#1); */
/* asm 2: fe_mul(>DA=z3,<D=tmp0,<A=x2); */
FieldOperations.fe_mul(out z3, ref tmp0, ref x2);
/* qhasm: CB = C*B */
/* asm 1: fe_mul(>CB=fe#2,<C=fe#2,<B=fe#6); */
/* asm 2: fe_mul(>CB=z2,<C=z2,<B=tmp1); */
FieldOperations.fe_mul(out z2, ref z2, ref tmp1);
/* qhasm: BB = B^2 */
/* asm 1: fe_sq(>BB=fe#5,<B=fe#6); */
/* asm 2: fe_sq(>BB=tmp0,<B=tmp1); */
FieldOperations.fe_sq(out tmp0, ref tmp1);
/* qhasm: AA = A^2 */
/* asm 1: fe_sq(>AA=fe#6,<A=fe#1); */
/* asm 2: fe_sq(>AA=tmp1,<A=x2); */
FieldOperations.fe_sq(out tmp1, ref x2);
/* qhasm: t0 = DA+CB */
/* asm 1: fe_add(>t0=fe#3,<DA=fe#4,<CB=fe#2); */
/* asm 2: fe_add(>t0=x3,<DA=z3,<CB=z2); */
FieldOperations.fe_add(out x3, ref z3, ref z2);
/* qhasm: assign x3 to t0 */
/* qhasm: t1 = DA-CB */
/* asm 1: fe_sub(>t1=fe#2,<DA=fe#4,<CB=fe#2); */
/* asm 2: fe_sub(>t1=z2,<DA=z3,<CB=z2); */
FieldOperations.fe_sub(out z2, ref z3, ref z2);
/* qhasm: X4 = AA*BB */
/* asm 1: fe_mul(>X4=fe#1,<AA=fe#6,<BB=fe#5); */
/* asm 2: fe_mul(>X4=x2,<AA=tmp1,<BB=tmp0); */
FieldOperations.fe_mul(out x2, ref tmp1, ref tmp0);
/* qhasm: E = AA-BB */
/* asm 1: fe_sub(>E=fe#6,<AA=fe#6,<BB=fe#5); */
/* asm 2: fe_sub(>E=tmp1,<AA=tmp1,<BB=tmp0); */
FieldOperations.fe_sub(out tmp1, ref tmp1, ref tmp0);
/* qhasm: t2 = t1^2 */
/* asm 1: fe_sq(>t2=fe#2,<t1=fe#2); */
/* asm 2: fe_sq(>t2=z2,<t1=z2); */
FieldOperations.fe_sq(out z2, ref z2);
/* qhasm: t3 = a24*E */
/* asm 1: fe_mul121666(>t3=fe#4,<E=fe#6); */
/* asm 2: fe_mul121666(>t3=z3,<E=tmp1); */
FieldOperations.fe_mul121666(out z3, ref tmp1);
/* qhasm: X5 = t0^2 */
/* asm 1: fe_sq(>X5=fe#3,<t0=fe#3); */
/* asm 2: fe_sq(>X5=x3,<t0=x3); */
FieldOperations.fe_sq(out x3, ref x3);
/* qhasm: t4 = BB+t3 */
/* asm 1: fe_add(>t4=fe#5,<BB=fe#5,<t3=fe#4); */
/* asm 2: fe_add(>t4=tmp0,<BB=tmp0,<t3=z3); */
FieldOperations.fe_add(out tmp0, ref tmp0, ref z3);
/* qhasm: Z5 = X1*t2 */
/* asm 1: fe_mul(>Z5=fe#4,x1,<t2=fe#2); */
/* asm 2: fe_mul(>Z5=z3,x1,<t2=z2); */
FieldOperations.fe_mul(out z3, ref x1, ref z2);
/* qhasm: Z4 = E*t4 */
/* asm 1: fe_mul(>Z4=fe#2,<E=fe#6,<t4=fe#5); */
/* asm 2: fe_mul(>Z4=z2,<E=tmp1,<t4=tmp0); */
FieldOperations.fe_mul(out z2, ref tmp1, ref tmp0);
/* qhasm: return */
}
FieldOperations.fe_cswap(ref x2, ref x3, swap);
FieldOperations.fe_cswap(ref z2, ref z3, swap);
FieldOperations.fe_invert(out z2, ref z2);
FieldOperations.fe_mul(out x2, ref x2, ref z2);
q = x2;
CryptoBytes.Wipe(e);
}