Hi Colin,
> StringSource SignatureFile(aSignature, true, new HexDecoder);
Was the signature run through a hex encoder?
I would also check the result of Signer::SignMessage() with the length
being passed into the verifier. I use code such as follows:
///////////////////////////////////////
// Signature
RSASS< PKCS1v15, SHA >::Signer signer( keys );
...
// Sign...
size_t length = signer.SignMessage( rng, (const byte*) message.c_str(),
message.length(), signature );
///////////////////////////////////////
// Verification
RSASS< PKCS1v15, SHA >::Verifier verifier( signer );
bool result = verifier.VerifyMessage( (const byte*)message.c_str(),
message.length(), signature, length );
Jeff
Sorry about not moving this to DSA for you. The stuff I have hanging
around used RSA.
On 1/21/08, Colin Bell <[EMAIL PROTECTED]> wrote:
>
> I have the following function (see below post) I wrote to verify
> signatures.
>
> The line
>
> StringSource SignatureFile(aSignature, true, new HexDecoder);
>
> fails to verify the signature
>
> but.. if I add the signature instead of passing it, it works!
>
> ie: StringSource
> SignatureFile("64237E8311F63386863CCE2BC6BB69E6216B0D569259AE3A10633FDECEAB445BF77569D2BEF0068B",
> true, new HexDecoder);
>
> Can anyone help?
>
> Many thanks
>
> Colin
>
> bool LicenseManager::validate(License license, string publicKey,
> string aSignature){
> StringSource pubFile(publicKey, true, new HexDecoder);
> StringSource SignatureFile(aSignature, true, new HexDecoder);
>
> // Verifier Object
> DSA::Verifier pub(pubFile);
>
> if (SignatureFile.MaxRetrievable() != pub.SignatureLength()){
> cerr << "Problem with the signature\n";
> return false;
> }
>
> SecByteBlock signature(pub.SignatureLength());
> SignatureFile.Get(signature, signature.size());
>
> // Setup
> VerifierFilter *verifierFilter = new VerifierFilter(pub);
> verifierFilter->Put(signature, pub.SignatureLength());
>
> // Invoke Verifier
> string message = license.getFingerprint();
> cout << "Fingerprint to verify is: \""<< message << "\"\n";
> StringSource(message, true, verifierFilter);
>
> if(verifierFilter->GetLastResult()){
> return true;
> }
> else{
> return false;
> }
> }
>
[ SNIP ]
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