I am new to CNG. I am playing with the basic program from msdn site. I have modified the input plain string and testing the output using other websites that provides the aes cbc encrypted output. Unfortunately only first half matches and the next half is not matching. It would be great if someone can point me where the mistake lies,
original code from msdn is here.
Here is the output generated from my code (below). Please note that there is no difference in my code apart from modifying the input plain string.
Here is the output from the online website (http://aes.online-domain-tools.com/ and anothersite)
The first half ends at "B0 C4 29 18".. after that the 2nd half doesn't match.
Here is the code snippet
#include <windows.h>
#include <stdio.h>
#include <bcrypt.h>
#pragma comment(lib, "bcrypt.lib")
#ifndef STATUS_UNSUCCESSFUL
#define STATUS_UNSUCCESSFUL ((NTSTATUS)0xC0000001L)
#endif // !STATUS_UNSUCCESSFUL
#ifndef NT_SUCCESS
#define NT_SUCCESS(Status) ((NTSTATUS)(Status) >= 0)
#endif
void
print_inhex(char *buf, int len) {
for (int i = 0; i < len; i++)
printf(" %02x", buf[i]);
printf("\n");
}
const BYTE rgbPlaintext[] =
{
0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f
};
static const BYTE rgbIV[] =
{
0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f
};
static const BYTE rgbAES128Key[] =
{
0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f
};
void
CNG_aes_cbc()
{
BCRYPT_ALG_HANDLE hAesAlg = NULL;
BCRYPT_KEY_HANDLE hKey = NULL;
NTSTATUS status = STATUS_UNSUCCESSFUL;
DWORD cbCipherText = 0,
cbPlainText = 0,
cbData = 0,
cbKeyObject = 0,
cbBlockLen = 0,
cbBlob = 0;
PBYTE pbCipherText = NULL,
pbPlainText = NULL,
pbKeyObject = NULL,
pbIV = NULL,
pbBlob = NULL;
// Open an algorithm handle.
if (!NT_SUCCESS(status = BCryptOpenAlgorithmProvider(&hAesAlg, BCRYPT_AES_ALGORITHM, NULL, 0))) {
wprintf(L"**** Error 0x%x returned by BCryptOpenAlgorithmProvider\n", status);
goto Cleanup;
}
// Calculate the size of the buffer to hold the KeyObject.
if (!NT_SUCCESS(status = BCryptGetProperty(hAesAlg, BCRYPT_OBJECT_LENGTH, (PBYTE)&cbKeyObject, sizeof(DWORD), &cbData, 0))) {
wprintf(L"**** Error 0x%x returned by BCryptGetProperty\n", status);
goto Cleanup;
}
// Allocate the key object on the heap.
pbKeyObject = (PBYTE)HeapAlloc(GetProcessHeap(), 0, cbKeyObject);
if (NULL == pbKeyObject) {
wprintf(L"**** memory allocation failed\n");
goto Cleanup;
}
// Calculate the block length for the IV.
if (!NT_SUCCESS(status = BCryptGetProperty(hAesAlg, BCRYPT_BLOCK_LENGTH, (PBYTE)&cbBlockLen, sizeof(DWORD), &cbData, 0))) {
wprintf(L"**** Error 0x%x returned by BCryptGetProperty\n", status);
goto Cleanup;
}
// Determine whether the cbBlockLen is not longer than the IV length.
if (cbBlockLen > sizeof(rgbIV)) {
wprintf(L"**** block length is longer than the provided IV length\n");
goto Cleanup;
}
// Allocate a buffer for the IV. The buffer is consumed during the
// encrypt/decrypt process.
pbIV = (PBYTE)HeapAlloc(GetProcessHeap(), 0, cbBlockLen);
if (NULL == pbIV) {
wprintf(L"**** memory allocation failed\n");
goto Cleanup;
}
memcpy(pbIV, rgbIV, cbBlockLen);
if (!NT_SUCCESS(status = BCryptSetProperty(hAesAlg, BCRYPT_CHAINING_MODE, (PBYTE)BCRYPT_CHAIN_MODE_CBC, sizeof(BCRYPT_CHAIN_MODE_CBC), 0))) {
wprintf(L"**** Error 0x%x returned by BCryptSetProperty\n", status);
goto Cleanup;
}
// Generate the key from supplied input key bytes.
if (!NT_SUCCESS(status = BCryptGenerateSymmetricKey(hAesAlg, &hKey, pbKeyObject, cbKeyObject, (PBYTE)rgbAES128Key, sizeof(rgbAES128Key), 0))) {
wprintf(L"**** Error 0x%x returned by BCryptGenerateSymmetricKey\n", status);
goto Cleanup;
}
// Save another copy of the key for later.
if (!NT_SUCCESS(status = BCryptExportKey(hKey, NULL, BCRYPT_KEY_DATA_BLOB, NULL, 0, &cbBlob, 0))) {
wprintf(L"**** Error 0x%x returned by BCryptExportKey\n", status);
goto Cleanup;
}
// Allocate the buffer to hold the BLOB.
PUCHAR pbBlob_1 = (PUCHAR)malloc(sizeof(PUCHAR) * cbBlob);
//pbBlob = (PBYTE)HeapAlloc(GetProcessHeap(), 0, cbBlob);
if (NULL == pbBlob_1) {
wprintf(L"**** memory allocation failed\n");
goto Cleanup;
}
if (!NT_SUCCESS(status = BCryptExportKey(hKey, NULL, BCRYPT_KEY_DATA_BLOB, pbBlob_1, cbBlob, &cbBlob, 0))) {
wprintf(L"**** Error 0x%x returned by BCryptExportKey\n", status);
goto Cleanup;
}
PUCHAR blob = pbBlob_1 + sizeof(BCRYPT_KEY_DATA_BLOB_HEADER);
int len = cbBlob - sizeof(BCRYPT_KEY_DATA_BLOB_HEADER);
printf("key:");
print_inhex(blob, len);
cbPlainText = sizeof(rgbPlaintext);
pbPlainText = (PBYTE)HeapAlloc(GetProcessHeap(), 0, cbPlainText);
if (NULL == pbPlainText) {
wprintf(L"**** memory allocation failed\n");
goto Cleanup;
}
/*memcpy(pbPlainText, rgbPlaintext, sizeof(rgbPlaintext));*/
char *test_msg = "This is my test msg";
cbPlainText = strlen(test_msg) + 1;
memcpy(pbPlainText, test_msg, cbPlainText);
printf("plain text:");
print_inhex(test_msg, strlen(test_msg));
// Get the output buffer size.
if (!NT_SUCCESS(status = BCryptEncrypt(hKey, pbPlainText, cbPlainText, NULL, pbIV, cbBlockLen, NULL, 0, &cbCipherText, BCRYPT_BLOCK_PADDING))) {
wprintf(L"**** Error 0x%x returned by BCryptEncrypt\n", status);
goto Cleanup;
}
pbCipherText = (PBYTE)HeapAlloc(GetProcessHeap(), 0, cbCipherText);
if (NULL == pbCipherText) {
wprintf(L"**** memory allocation failed\n");
goto Cleanup;
}
// Use the key to encrypt the plaintext buffer.
// For block sized messages, block padding will add an extra block.
if (!NT_SUCCESS(status = BCryptEncrypt(hKey, pbPlainText, cbPlainText, NULL, pbIV,
cbBlockLen, pbCipherText, cbCipherText, &cbData, BCRYPT_BLOCK_PADDING))){
wprintf(L"**** Error 0x%x returned by BCryptEncrypt\n", status);
goto Cleanup;
}
printf("cipher text:");
for (int i = 0; i < cbCipherText; i++)
printf(" %02x", pbCipherText[i]);
wprintf(L"\nSuccess!\n");
Cleanup:
if (hAesAlg)
BCryptCloseAlgorithmProvider(hAesAlg, 0);
if (hKey)
BCryptDestroyKey(hKey);
if (pbCipherText)
HeapFree(GetProcessHeap(), 0, pbCipherText);
if (pbKeyObject)
HeapFree(GetProcessHeap(), 0, pbKeyObject);
if (pbIV)
HeapFree(GetProcessHeap(), 0, pbIV);
}
