I wanted to use the ECP scheme for it's short keys. But I guess that is out the door once hashing comes into play. Unless we use a TrueHASH.
- Ron On 11/29/06, Jeffrey Walton <[EMAIL PROTECTED]> wrote:
Hi Ron, Take a look at RSA's scheme. Wei provides a sample in test.cpp, and one of the validates - validate1.cpp, etc. Jeff On 11/29/06, Ron B <[EMAIL PROTECTED]> wrote: > I'm trying to implement a secure key system for my application based on the > ideas posted here > > http://www.codeproject.com/useritems/ECIESProductKey.asp > > The mechanism there relies on the server for authentication I don't want to > put my users through that so I want to authenticate in the application thus > I would need > some way of decrypting a short message with a public key. The post above > suggests " Signature Scheme with Message Recovery" for my case so I am > trying to use > ECP and SignMessageWithRecovery however my code keeps reporting > signer.MaxRecoverableLength=0 and throws an error: > > Crypto++ Error: PK_MessageEncodingMethod: this signature scheme does not > support message recovery. > > Key parts of my code: > > CryptoPP::ECIES< CryptoPP::ECP >::Decryptor decryptor( PrivateKey ); > CryptoPP::ECDSA< CryptoPP::ECP , CryptoPP::SHA>::Signer signer( decryptor ); > printf("Max Recov. %d\n",signer.MaxRecoverableLength()); > CryptoPP::SecByteBlock signature(signer.MaxSignatureLength(messageLen)); > unsigned int signatureLen = signer.SignMessageWithRecovery(rng, message, > messageLen, NULL, 0, signature); > > Is this a problem in my code, a library limitation or a even elliptic curve > cryptography limitation? > > Thanks, > > Ron >
