Hi, everyone.
In Openssl 0.9.8i, I'm trying to take an RSA public exponent and public
modulus, assemble them into an RSA key, and use that to verify a
signature for a message. However, EVP_VerifyFinal() always fails,
apparently because of the wrong use of padding.
My code:
RSA * RsaKeyPtr = RSA_new();
EVP_PKEY * EvpKeyPtr = EVP_PKEY_new();
RsaKeyPtr->n = BN_bin2bn(ModulusPtr, ModulusLength, NULL); // Public
modulus n
RsaKeyPtr->e = BN_bin2bn(Exponent, sizeof(Exponent), NULL); // Public
key exponent e
EvpKeyPtr->type = EVP_PKEY_RSA;
if(EVP_PKEY_assign_RSA(EvpKeyPtr, RsaKeyPtr))
{
EVP_MD_CTX_init(&MDContext);
if(EVP_VerifyInit_ex(&MDContext, EvpMdPtr, NULL))
{
if(EVP_VerifyUpdate(&MDContext, MessagePtr, MessageLength))
{
if(EVP_VerifyFinal(&MDContext, SignaturePtr,
SignatureLength, EvpKeyPtr))
{
...
The call stack looks like:
RSA_public_decrypt((int)siglen,sigbuf,s,rsa,RSA_PKCS1_PADDING);
...
RSA_eay_public_decrypt()
RSA_padding_check_PKCS1_type_1()
and that last function fails.
Am I assembling the RSA key incorrectly?
The modulus and exponent are each 1024 bits long and the message and
signature are each 128 bytes long
Thanks very much,
Paul
___________________________________
Paul A. Suhler | Firmware Engineer | Quantum Corporation | Office:
949.856.7748 | paul.suh...@quantum.com
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