Very Strange Question on RSA Decrypt.

David Mon, 26 May 2003 12:53:19 -0400 (EDT)

Hi, there,

I am trying to use RSA to encypt and decrypt something,

here, I got very strange problem(crypto++library is 4.2),

after encryption, I try to decrypt, here is the code,

                char* privStr = new char[2*privateLength+1];
                HexEncoder hexEncoder;
                hexEncoder.Put((byte *)privateKeyStr, privateLength);
                hexEncoder.MessageEnd();
                hexEncoder.Get((byte *)privStr, 2*privateLength);
                privStr[2*privateLength] = 0;

StringSource privRSAKey(privStr, true, new HexDecoder);
RSAES_PKCS1v15_Decryptor privatekey(privRSAKey);

I always got a exception here,

BERGeneralDecoder::BERGeneralDecoder(BufferedTransformation &inQueue, byte asnTag)
: m_inQueue(inQueue), m_finished(false)
{
byte b;
if (!m_inQueue.Get(b) || b != asnTag)
BERDecodeError(); <----------------------------------the exception I always got here.

m_definiteLength = BERLengthDecode(m_inQueue, m_length);
}

But if change the original code like this way, directly define a private key,

there is no any problem, can get the result decypted text.

char* privStr = new char[2*privateLength+1];

privStr="30820152020100300D06092A864886F70D01010105000482013C27B46E92C878558F7C819");

StringSource privRSAKey(privStr, true, new HexDecoder);
RSAES_PKCS1v15_Decryptor privatekey(privRSAKey);

BTW, I do the encryption and decryption separately.

when I encrypt, use the codes like the decrypt, not any problem

                char* pubstr = new char[2*publicLength+1];
                HexEncoder hexEncoder;
                hexEncoder.Put((byte *)publicKeyStr, publicLength);
                hexEncoder.MessageEnd();
                hexEncoder.Get((byte *)pubstr, 2*publicLength);
                pubstr[2*publicLength] = 0;

StringSource* pubRSAKey = new StringSource(pubstr ,true,new HexDecoder);
RSAES_PKCS1v15_Encryptor* pubkey = new RSAES_PKCS1v15_Encryptor(*pubRSAKey);

I got confused and do not why?

anyone can help me figure it out.

thanks

David

Very Strange Question on RSA Decrypt.

Reply via email to