- 1 year ago
Getting BCrypt_Key_Handle from RSA 2048 public key in PEM format
To obtain a BCrypt_Key_Handle
from an RSA 2048 public key in PEM format using the Windows Cryptographic API (CNG), you can follow these steps in C++:
Load the RSA public key from the PEM file:
- Use a library like OpenSSL or a custom implementation to read the RSA public key from the PEM file and obtain the raw key data.
Import the RSA public key using the CryptImportPublicKeyInfo function:
- Create a
CRYPT_PUBLIC_KEY_INFO
structure from the raw key data. - Use the
CryptImportPublicKeyInfo
function to import the public key and obtain aBCrypt_Key_Handle
.
- Create a
Here's an example code snippet that demonstrates the process:
cpp#include <windows.h>
#include <bcrypt.h>
#include <wincrypt.h>
#include <stdio.h>
int main()
{
// Load the RSA public key from the PEM file and obtain raw key data
// (Code to read the PEM file and extract the raw key data)
// Create a CRYPT_PUBLIC_KEY_INFO structure
CRYPT_PUBLIC_KEY_INFO publicKeyInfo;
publicKeyInfo.Algorithm.pszObjId = szOID_RSA_RSA;
publicKeyInfo.Algorithm.Parameters.cbData = 0;
publicKeyInfo.Algorithm.Parameters.pbData = NULL;
publicKeyInfo.PublicKey.cbData = /* Set the size of the raw key data */;
publicKeyInfo.PublicKey.pbData = /* Set the raw key data */;
// Import the RSA public key
HCRYPTPROV hProv = NULL;
BCryptOpenAlgorithmProvider(&hProv, BCRYPT_RSA_ALGORITHM, NULL, 0);
BCRYPT_KEY_HANDLE hKey = NULL;
CryptImportPublicKeyInfo(hProv, X509_ASN_ENCODING | PKCS_7_ASN_ENCODING, &publicKeyInfo, &hKey);
// Use the hKey BCrypt_Key_Handle for further operations with the RSA public key
// (e.g., encryption or verification)
// Clean up
CryptDestroyKey(hKey);
BCryptCloseAlgorithmProvider(hProv, 0);
return 0;
}
In the above code, replace the sections marked with comments (/* ... */
) with the actual implementation to load the RSA public key from the PEM file and extract the raw key data.
Ensure that you have included the necessary header files (windows.h
, bcrypt.h
, wincrypt.h
) and link against the Bcrypt.lib
library. Also, make sure to handle errors and perform necessary cleanup operations.
Please note that the code provided is a basic example and may require additional error handling, input validation, and adjustments based on your specific requirements and environment.