/// <summary>
/// Get compressed and compact signature (possible in not canonical form)
/// </summary>
/// <param name="data">Hashed data</param>
/// <param name="seckey">Private key (32 bytes)</param>
/// <returns> 65 bytes compressed / compact</returns>
public static byte[] SignCompressedCompact(byte[] data, byte[] seckey)
{
if (data == null)
{
throw new ArgumentNullException(nameof(data));
}
if (data.Length == 0)
{
throw new ArgumentOutOfRangeException(nameof(data));
}
if (seckey == null)
{
throw new ArgumentNullException(nameof(seckey));
}
if (seckey.Length != 32)
{
throw new ArgumentOutOfRangeException(nameof(seckey));
}
byte recoveryId = 0;
secp256k1_ecdsa_recoverable_signature sig = new secp256k1_ecdsa_recoverable_signature();
byte loop = 0;
int index = 0;
bool rec;
byte[] extra = null;
Random r = new Random();
do
{
if (loop == 0xff)
{
index = index + 1; loop = 0;
}
if (loop > 0)
{
extra = new byte[32];
r.NextBytes(extra);
}
loop++;
rec = secp256k1_ecdsa_sign_recoverable(Ctx, sig, data, seckey, null, extra);
} while (!(rec && is_canonical(sig.data)));
var output65 = new byte[65];
secp256k1_ecdsa_recoverable_signature_serialize_compact(Ctx, output65, 1, out recoveryId, sig);
//4 - compressed | 27 - compact
output65[0] = (byte)(recoveryId + 4 + 27);
return(output65);
}
private static void secp256k1_ecdsa_recoverable_signature_save(secp256k1_ecdsa_recoverable_signature sig, secp256k1_scalar r, secp256k1_scalar s, byte recid)
{
if (secp256k1_scalar.Size == 32)
{
Util.Memcpy(r.d, 0, sig.data, 0, 32); // memcpy(&sig.data[0], r, 32);
Util.Memcpy(s.d, 0, sig.data, 32, 32); // memcpy(&sig->data[32], s, 32);
}
else
{
Scalar.secp256k1_scalar_get_b32(sig.data, 0, r);
Scalar.secp256k1_scalar_get_b32(sig.data, 32, s);
}
sig.data[64] = recid;
}
/// <summary>Signs a data and returns the signature in compact form. Returns null on failure.</summary>
/// <param name="dataage">The data to sign. This data is not hashed. For use with bitcoins, you probably want to double-SHA256 hash this before calling this method.</param>
/// <param name="seckeyeKey">The private key to use to sign the data.</param>
/// <param name="recoveryId">This will contain the recovery ID needed to retrieve the key from the compact signature using the RecoverKeyFromCompact method.</param>
public static byte[] SignCompact(byte[] data, byte[] seckey, out int recoveryId)
{
if (data == null)
{
throw new ArgumentNullException(nameof(data));
}
if (data.Length == 0)
{
throw new ArgumentOutOfRangeException(nameof(data));
}
if (seckey == null)
{
throw new ArgumentNullException(nameof(seckey));
}
if (seckey.Length != 32)
{
throw new ArgumentOutOfRangeException(nameof(seckey));
}
recoveryId = 0;
secp256k1_ecdsa_recoverable_signature sig = new secp256k1_ecdsa_recoverable_signature();
{
if (!secp256k1_ecdsa_sign_recoverable(Ctx, sig, data, seckey, null, null))
{
return(null);
}
}
var sigbytes = new byte[64];
byte recid;
{
if (!secp256k1_ecdsa_recoverable_signature_serialize_compact(Ctx, sigbytes, out recid, sig))
{
return(null);
}
}
recoveryId = recid;
return(sigbytes);
}
private static byte[] sign_compact(byte[] data, byte[] seckey, out byte recoveryId)
{
secp256k1_ecdsa_recoverable_signature sig = new secp256k1_ecdsa_recoverable_signature();
byte loop = 0;
int index = 0;
bool rec;
var extra = new byte[32];
do
{
extra[index] = loop++;
if (loop == 0xff)
{
index = index + 1; loop = 0;
}
rec = secp256k1_ecdsa_sign_recoverable(Ctx, sig, data, seckey, null, extra);
} while (!rec);
var output64 = new byte[64];
secp256k1_ecdsa_recoverable_signature_serialize_compact(Ctx, output64, out recoveryId, sig);
return(output64);
}
private static int sign_compact(secp256k1_context ctx, byte[] msg32, byte[] seckey, byte[] output64, out byte recid)
{
secp256k1_ecdsa_recoverable_signature sig = new secp256k1_ecdsa_recoverable_signature();
byte loop = 0;
int index = 0;
bool rec = false;
var extra = new byte[32];
do
{
extra[index] = loop;
loop++;
if (extra[index] == 0xff)
{
index = index + 1;
}
rec = secp256k1_ecdsa_sign_recoverable(ctx, sig, msg32, seckey, null, extra);
} while (!rec);
secp256k1_ecdsa_recoverable_signature_serialize_compact(ctx, output64, out recid, sig);
return(loop);
}
private static void secp256k1_ecdsa_recoverable_signature_load(secp256k1_context ctx, secp256k1_scalar r, secp256k1_scalar s, out byte recid, secp256k1_ecdsa_recoverable_signature sig)
{
//(void)ctx;
if (secp256k1_scalar.Size == 32)
{
/* When the secp256k1_scalar type is exactly 32 byte, use its
* representation inside secp256k1_ecdsa_signature, as conversion is very fast.
* Note that secp256k1_ecdsa_signature_save must use the same representation. */
Util.Memcpy(sig.data, 0, r.d, 0, 32); //memcpy(r, &sig->data[0], 32);
Util.Memcpy(sig.data, 32, s.d, 0, 32); //memcpy(s, &sig->data[32], 32);
}
else
{
Scalar.secp256k1_scalar_set_b32(r, sig.data, 0);
Scalar.secp256k1_scalar_set_b32(s, sig.data, 32);
}
recid = sig.data[64];
}
private static bool secp256k1_ecdsa_recoverable_signature_serialize_compact(secp256k1_context ctx, byte[] outputxx, int skip, out byte recid, secp256k1_ecdsa_recoverable_signature sig)
{
secp256k1_scalar r = new secp256k1_scalar();
secp256k1_scalar s = new secp256k1_scalar();
recid = 0;
if (outputxx == null)
{
ctx.illegal_callback?.Invoke(null, new secp256k1_callback("(outputxx != null)"));
return(false);
}
//___________________________________________________________________________________________________________________________________
if (sig == null)
{
ctx.illegal_callback?.Invoke(null, new secp256k1_callback("(sig != null)"));
return(false);
}
//___________________________________________________________________________________________________________________________________
secp256k1_ecdsa_recoverable_signature_load(ctx, r, s, out recid, sig);
Scalar.secp256k1_scalar_get_b32(outputxx, skip + 0, r);
Scalar.secp256k1_scalar_get_b32(outputxx, skip + 32, s);
return(true);
}
private static bool secp256k1_ecdsa_recoverable_signature_serialize_compact(secp256k1_context ctx, byte[] output64, out byte recid, secp256k1_ecdsa_recoverable_signature sig)
{
return(secp256k1_ecdsa_recoverable_signature_serialize_compact(ctx, output64, 0, out recid, sig));
}
private static bool secp256k1_ecdsa_sign_recoverable(secp256k1_context ctx, secp256k1_ecdsa_recoverable_signature signature,
byte[] msg32, byte[] seckey, secp256k1_nonce_function noncefp, byte[] noncedata)
{
if (ctx == null || msg32 == null || signature == null || seckey == null)
{
throw new NullReferenceException();
}
if (!ECMultGen.secp256k1_ecmult_gen_context_is_built(ctx.ecmult_gen_ctx))
{
throw new ArithmeticException();
}
if (noncefp == null)
{
noncefp = Secp256k1.secp256k1_nonce_function_default;
}
secp256k1_scalar r, s;
secp256k1_scalar sec, non, msg;
byte recid = 1;
bool ret = false;
var overflow = false;
sec = new secp256k1_scalar();
Scalar.secp256k1_scalar_set_b32(sec, seckey, ref overflow);
r = new secp256k1_scalar();
s = new secp256k1_scalar();
/* Fail if the secret key is invalid. */
if (!overflow && !Scalar.secp256k1_scalar_is_zero(sec))
{
var nonce32 = new byte[32];
uint count = 0;
msg = new secp256k1_scalar();
Scalar.secp256k1_scalar_set_b32(msg, msg32);
non = new secp256k1_scalar();
while (true)
{
ret = noncefp(nonce32, msg32, seckey, null, noncedata, count);
if (!ret)
{
break;
}
Scalar.secp256k1_scalar_set_b32(non, nonce32, ref overflow);
if (!Scalar.secp256k1_scalar_is_zero(non) && !overflow)
{
if (secp256k1_ecdsa_sig_sign(ctx.ecmult_gen_ctx, r, s, sec, msg, non, out recid))
{
break;
}
}
count++;
}
Util.MemSet(nonce32, 0, 32); //memset(nonce32, 0, 32);
Scalar.secp256k1_scalar_clear(msg);
Scalar.secp256k1_scalar_clear(non);
Scalar.secp256k1_scalar_clear(sec);
}
if (ret)
{
secp256k1_ecdsa_recoverable_signature_save(signature, r, s, recid);
}
else
{
Util.MemSet(signature.data, 0, secp256k1_ecdsa_recoverable_signature.Size); //memset(signature, 0, sizeof(* signature));
}
return(ret);
}