- 1 year ago
How to create a AES persistent key with Crypto API Next Generation on Windows 7
Creating a persistent AES key using Crypto API Next Generation (CNG) on Windows 7 involves several steps. CNG is a modern cryptographic framework that provides enhanced security features compared to the older Crypto API. Here's how you can create a persistent AES key using CNG:
Include Necessary Headers:
Include the necessary headers in your C/C++ code:c#include <windows.h>
#include <bcrypt.h>
Initialize CNG Provider:
Before using CNG functions, you need to initialize the provider. You can use the BCryptOpenAlgorithmProvider function for this purpose:cBCRYPT_ALG_HANDLE hAlgorithm;
if (BCryptOpenAlgorithmProvider(&hAlgorithm, BCRYPT_AES_ALGORITHM, NULL, 0) != STATUS_SUCCESS) {
// Handle error
}
Generate AES Key Pair:
Use the BCryptGenerateSymmetricKey function to generate an AES key pair. TheBCRYPT_KEY_HANDLE
represents the key:cBCRYPT_KEY_HANDLE hKey;
if (BCryptGenerateSymmetricKey(hAlgorithm, &hKey, NULL, 0, (PUCHAR)keyData, keyDataSize, 0) != STATUS_SUCCESS) {
// Handle error
}
Make the Key Persistent:
To make the key persistent, you can use the NCryptPersistKey function. This requires obtaining anNCRYPT_KEY_HANDLE
from theBCRYPT_KEY_HANDLE
:cNCRYPT_KEY_HANDLE hNcryptKey;
if (NCryptImportKey(hAlgorithm, NULL, BCRYPT_AES_KEY_OBJECT, NULL, &hNcryptKey, (PUCHAR)keyData, keyDataSize, 0) != STATUS_SUCCESS) {
// Handle error
}
Close Handles:
After you're done with the key, make sure to close the handles:cBCryptDestroyKey(hKey);
NCryptFreeObject(hNcryptKey);
BCryptCloseAlgorithmProvider(hAlgorithm, 0);
Error Handling:
Be sure to add appropriate error handling and check return values for each function call.
Remember that CNG is a complex API, and this is just a basic example of how to create a persistent AES key. You need to handle various error cases, memory management, and additional options based on your specific requirements.
Lastly, while using CNG provides enhanced security, you should consider using a higher-level cryptographic library like OpenSSL or libraries provided by programming languages (like Python's cryptography
module) for easier and more standardized cryptographic operations.