c++ - C++ Microsoft CryptoAPI 中的 AES/Rijndael

Question

如何使用 Microsoft CryptoAPI（CryptDeriveKey、BCrypt[...] 函数、CryptAcquireContext 等）将以下加密代码（VB.NET 4.0）转换为等效的 C++ 代码？（我在 Internet 上没有找到一篇描述使用 Microsoft CryptoAPI 的 AES 的文章……）

Dim Key(31) As Byte
Dim IV(15) As Byte

Array.Copy(SomeByteArray, IV, 16)
Array.Copy((New SHA512Managed).ComputeHash(SomeByteArray), Key, 32)

Using AESEncr As New RijndaelManaged() With {.Padding = PaddingMode.ISO10126}

    FinalEncrypted = AESEncr.CreateEncryptor(Key, IV).TransformFinalBlock(AnotherByteArray, 0, AnotherByteArray.GetLength(0))

End Using

和解密一个：

Dim Key(31) As Byte
Dim IV(15) As Byte

Array.Copy(SomeByteArray, IV, 16)
Array.Copy((New SHA512Managed).ComputeHash(SomeByteArray), Key, 32)

Using AESEncr As New RijndaelManaged() With {.Padding = PaddingMode.ISO10126}

    FinalDecrypted = AESEncr.CreateDecryptor(Key, IV).TransformFinalBlock(FinalEncrypted, 0, FinalEncrypted.GetLength(0))

End Using

（注意：我已经有关于 SHA-512 方法的 C++ 代码，所以不要为此烦恼。）

Answer 1

因此，我为 AES-256 加密/解密编写的代码如下：（它采用BYTE* Data和BYTE* IV作为参数）

    BYTE *hash, *res;
    HCRYPTPROV hCrypt = NULL;
    HCRYPTKEY hKey = NULL;

    struct {
        BLOBHEADER hdr;
        DWORD len;
        BYTE key[32];
    } key_blob;

    key_blob.hdr.bType = PLAINTEXTKEYBLOB;
    key_blob.hdr.bVersion = CUR_BLOB_VERSION;
    key_blob.hdr.reserved = 0;
    key_blob.hdr.aiKeyAlg = CALG_AES_256;
    key_blob.len = 32;

    hash = ComputeSHA512Hash(IV);
    copy(hash, hash + 32, key_blob.key);

    res = new BYTE[16];
    copy(Data, Data + 15, res);
    res[15] = 0;

    // Get the Microsoft Enhanced RSA and AES Cryptographic Service Provider

    if (!CryptAcquireContext(&hCrypt, NULL, MS_ENH_RSA_AES_PROV, PROV_RSA_AES, 0))
        throw E_FAIL;

    // Import our key blob

    if (!CryptImportKey(hCrypt, (BYTE *)&key_blob, sizeof(key_blob), NULL, 0, &hKey))
        throw E_FAIL;

    // Set the mode to Cipher Block Chaining

    DWORD dwMode = CRYPT_MODE_CBC;

    if (!CryptSetKeyParam(hKey, KP_MODE, (BYTE *)&dwMode, 0))
        throw E_FAIL;

    // Set the Initialization Vector to ours

    if (!CryptSetKeyParam(hKey, KP_IV, IV, 0))
        throw E_FAIL;

    // Do the main encryption

    DWORD pdwDataLen = 15;

    if (!CryptEncrypt(hKey, NULL, TRUE, 0, res, &pdwDataLen, 16))
        throw E_FAIL;

    // Do the main decryption

    pdwDataLen = 16;

    if (!CryptDecrypt(hKey, NULL, TRUE, 0, res, &pdwDataLen))
        throw E_FAIL;

     // Destroy whatever was created before (free memory)

     delete hash;

     delete res;

     if (hKey)
            CryptDestroyKey(hKey);

     if (hCrypt)
            CryptReleaseContext(hCrypt, 0);

正如我之前所说，我已经有了 ComputeSHA512Hash() 函数的代码，所以我的代码对于我的目的来说是完整的。我希望这段代码对想要编写 AES-256 代码的每个人都有用。