RE: How to use szOID_PKCS_1 ID to encrypt?
- From: lelteto <lelteto@xxxxxxxxxxxxxxxxxxxxxxxxx>
- Date: Thu, 17 Apr 2008 08:54:00 -0700
Even with only four bytes you don't encrypt data directly with PKCS#1. What
you do is
1. pick a good SYMMETRIC crypto algo (AES is preferred, but for first
testing you can stick with RC4)
2. generate a RANDOM secret key (called session key)
3. encrypt your data using the key from 2 with ango 1
4. encrypt (wrap) the key 2 with an RSA public key
Send the recipien both 3 (encrypted data) and 4 (encrypted key)
Now the recipient will first decrypt the secret key using the RSA private
key then decrypt the data using that key.
Laszlo Elteto
SafeNet, Inc.
"Raj" wrote:
Hi,.
I have to encrypt a 4 byte value with PKCS#1 algorithm.
I am using CryptEncryptMessage API with szOID_PKCS_1 as Object ID in
CRYPT_ALGORITHM_IDENTIFIER sturcture. API is returing following error code.
0x80091002 :: Unknown cryptographic algorithm.
This is really my first attempt to use Crypto API and new to RSA algorithms.
Please let me know how to use Crypto API to encrypt with szOID_PKCS_1.
Here I am posting the code what I used. I found the code in MSDN and just
changed algorithm ID. When I try with szOID_RSA_RC4, API is encrypting.
pCertContext = CertCreateCertificateContext(X509_ASN_ENCODING,
pDecodedCert, iDecodedCertSize);
free(pDecodedCert);
if(pCertContext == NULL)
{
//*ErrorCode = GetLastError();
return NULL;
}
///Prepare for encryption
PCCERT_CONTEXT RecipientCertArray[1];
CRYPT_ENCRYPT_MESSAGE_PARA EncryptParams={0};
CRYPT_ALGORITHM_IDENTIFIER EncryptAlgorithm={0};
DWORD
EncryptAlgSize=sizeof(EncryptAlgorithm),EncryptParamsSize=sizeof(EncryptParams),cbEncryptedBlob=0;
BYTE* pbEncryptedBlob = NULL;
// Create a RecipientCertArray.
RecipientCertArray[0] = pCertContext;
// Initialize the algorithm identifier structure.
EncryptAlgorithm.pszObjId = szOID_PKCS_1;
// Initialize the CRYPT_ENCRYPT_MESSAGE_PARA structure.
EncryptParams.cbSize = EncryptParamsSize;
EncryptParams.dwMsgEncodingType = PKCS_7_ASN_ENCODING | X509_ASN_ENCODING ;
EncryptParams.hCryptProv = NULL;
EncryptParams.ContentEncryptionAlgorithm = EncryptAlgorithm;
if(CryptEncryptMessage(&EncryptParams,1,RecipientCertArray,(const
PBYTE)&m_IssueSeed,sizeof(m_IssueSeed),NULL,&cbEncryptedBlob))
{
pbEncryptedBlob = (PBYTE)malloc(cbEncryptedBlob);
if(CryptEncryptMessage(&EncryptParams,1,RecipientCertArray,(const
PBYTE)&m_IssueSeed,sizeof(m_IssueSeed),pbEncryptedBlob,&cbEncryptedBlob))
{
//success.
}
else
{
//*ErrorCode = GetLastError();
}
}
else
{
//*ErrorCode = GetLastError();
}
- References:
- How to use szOID_PKCS_1 ID to encrypt?
- From: Raj
- How to use szOID_PKCS_1 ID to encrypt?
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