On Wed, Feb 6, 2019 at 6:24 AM <[email protected]> wrote:
>
> I called the method SetPublicElement and I performed trials with both "02"
> and "03", but the verification stil return error.
>
> Code is:
> int main () {
> using namespace CryptoPP;
> AutoSeededRandomPool rnd;
>
> ECDSA<ECP, SHA256>::PublicKey pubKey;
> HexDecoder decoder;
> string compactPoint;
> string message =
> "4003805520500000003101001400ba749705a41d251799c60000000000000000000000000000000007d1000001029705"
>
> "a41d99c6405d693a403ad274803ffffffc23b7743e40e11fdffffe3fe9ed073753085fffa0000000004001240000006d251a3fe2";
> string signature =
> "26413d411d233adc8baf8d4401036ffd511ed996d862ce4e106275d9851339d7";
> compactPoint = "02"
> "937120662418500f3ad7c892b1db7e7c2d85ec48c74e99d64dcb7083082bb4f3";
> //compactPoint = "03"
> "937120662418500f3ad7c892b1db7e7c2d85ec48c74e99d64dcb7083082bb4f3";
>
> pubKey.AccessGroupParameters().Initialize(ASN1::secp256r1());
> StringSource ss (compactPoint, true, new CryptoPP::HexDecoder);
> ECP::Point point;
>
> pubKey.GetGroupParameters().GetCurve().DecodePoint (point, ss,
> ss.MaxRetrievable());
>
> std::cout << "Result after decompression X: " << std::hex << point.x <<
> std::endl;
> std::cout << "Result after decompression Y: " << std::hex << point.y <<
> std::endl;
>
> pubKey.SetPublicElement (point);
>
> cout << "Is valid? " << pubKey.Validate (rnd, 3) << std::endl;
>
> cout <<
> "\n\n==================================================\n==================================================\n";
>
> ECDSA<ECP,SHA256>::Verifier verifier(pubKey);
> bool result;
> StringSource ss1( signature+message, true, new
> SignatureVerificationFilter (verifier,new ArraySink( (byte*)&result,
> sizeof(result))));
>
> // Verification failure?
> if (!result)
> cout << "Error on verify: " << result << endl << endl;
> else
> cout << "Success on verify: " << result << endl << endl;
>
> return 0;
> }
You need to HexDecode the signature and message Something like:
std::string m, s;
StringSource(message, true, new HexDecoder(new StringSink(m)));
StringSource(signature, true, new HexDecoder(new StringSink(s)));
Then use something like:
StringSource ss( s+m, true, new SignatureVerificationFilter (...));
But the signature length looks wrong to me. secp256 and SHA256 should
be producing 64-byte signatures, not 32-byte signatures:
$ echo -n 26413d411d233adc8baf8d4401036ffd511ed996d862ce4e106275d9851339d7
| wc -c
64
Because it is hex encoded, 64/2 = 32 bytes.
You need to get the specs from the folks who are providing the keys,
message and signature.
Jeff
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