【发布时间】：2017-08-18 02:03:59
【问题描述】：
我是 CNG 的新手。我正在玩 msdn 网站上的基本程序。 我已经修改了输入纯字符串并使用其他提供 aes cbc 加密输出的网站测试了输出。 不幸的是只有上半场比赛，下半场没有比赛。 如果有人能指出错误所在，那就太好了，
msdn 的原始代码是here。
这是我的代码生成的输出（如下）。请注意，除了修改输入的纯字符串外，我的代码没有任何区别。
这是来自在线网站的输出（http://aes.online-domain-tools.com/ 和 anothersite）
前半场以“B0 C4 29 18”结束..之后第二半场不匹配。
这里是代码sn-p
#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);
}
【问题讨论】：
-
IV 不是 256 位的，它是十六进制的 w=这里每个字符代表 4 位，32 字符 * 4 位 = 128 位。也不要在屏幕截图中提供输入、键和 IV。
-
但是我在我的程序和在线网站中也使用了相同的 IV.. 他们都没有抱怨.. 这是来自 msdn 的相同代码，所以我假设 IV 可能不是问题。
-
数据的长度不是块大小的精确倍数（AES 为 16 字节），因此添加了填充但是。那就是实现要么拒绝数据，要么使用默认方法填充，例如 0x00（密码学）、PKCS#7（通常使用的填充）或任何 junbk 跟随内存中提供的数据。最好在 AES 实例化时指定填充。
-
感谢您的回复...根据msdn.microsoft.com/en-us/library/windows/desktop/…...对于对称密钥，唯一允许的选项是 0 或 BCRYPT_BLOCK_PADDING... 它没有谈论“填充 AES 实例化” ..您能否提供更多详细信息如何使用 CNG 执行此操作。
标签： c++ encryption aes padding cng