encryption - C++Openssl 截断 JSON 输入

Question

我正在开发一个项目，该项目涉及加密一个 json 字符串（4000+ 个字符长），然后在通过 CURL 发布到 PHP 后对其进行解密。我已经让 openssl 库工作和编译，它能够将类似的 json 数据加密保存到二进制文件中，读取它，解密它并使用它。只要我只尝试加密字符串并发布它，openssl 就会截断数据。数据包含特殊字符（utf8mb4），但由于它可以很好地写入文件，我对它为什么拒绝加密整个字符串感到困惑。我使用 32 字节（256 位）密钥和 16 字节（128 位）iv 尝试了以下操作：

AES-256-CBC AES-256-CFB AES-256-ECB AES-256-GCM

较短的字符串可以正常工作（即 < 175 个字符）。但较长的字符串（例如 JSON 有效负载）不起作用。即使是 openssl 自己的示例代码也不加密有效载荷。

主要功能（用于测试）：https ://pastebin.com/ZrpSd88W

int main()
{
    OpenSSL_add_all_algorithms();
    ERR_load_crypto_strings();

    /* Set up the key and iv. Do I need to say to not hard code these in a real application? :-) */

    /* A 256 bit key */
    static const unsigned char key[] = "01234567890123456789012345678901";

    /* A 128 bit IV */
    static const unsigned char iv[] = "0123456789012345";

    /* Message to be encrypted */
    unsigned char plaintext[] = "The quick brown fox jumps over the lazy dog";

    /* Some additional data to be authenticated */
    static const unsigned char aad[] = "Some AAD data";





    int decryptedtext_len = 0, ciphertext_len = 0;


    printf("");
    printf("");
    printf("");
    printf("");
    printf("");
    printf("");
    printf("");

    curl_global_init(CURL_GLOBAL_ALL);


    std::string data = "{ \"jobData\": {\"isMultiplayer\": false,\"late\": false,\"sourceCity\": \"Düsseldorf\",\"sourceCompany\": \"Stokes\",\"destinationCity\": \"Duisburg\",\"destinationCompany\": \"LkwLog GmbH\",\"cargo\": \"Wheat\",\"truckMake\": \"Volvo\",\"truckModel\": \"FH16 Classic\",\"game\": \"Euro Truck Simulator 2\",\"sourceCityID\": \"dusseldorf\",\"sourceCompanyID\": \"stokes\",\"destinationCityID\": \"duisburg\",\"destinationCompanyID\": \"lkwlog\",\"cargoID\": \"wheat\",\"truckMakeID\": \"volvo\",\"truckModelID\": \"vehicle.volvo.fh16\",\"gameID\": \"ets2\",\"gameVersion\": \"1.13\",\"pluginVersion\": \"0.15.365.0\",\"income\": 799,\"trailerMass\": 17140,\"distanceDriven\": 7.56641,\"fuelBurned\": 4.75964,\"fuelPurchased\": 0,\"startOdometer\": 64493,\"endOdometer\": 64500.6,\"collisionCount\": 3,\"finishTrailerDamage\": 0.0201135,\"startTrailerDamage\": 0,\"deliveryX\": -13184.1,\"deliveryY\": 58.2873,\"deliveryZ\": -6147.25,\"pickupX\": -13147.2,\"pickupY\": 48.0304,\"pickupZ\": -4555.74,\"trailerDeliveryX\": -13184.2,\"trailerDeliveryY\": 58.2863,\"trailerDeliveryZ\": -6152.03,\"trailerPickupX\": -13147.2,\"trailerPickupY\": 48.0285,\"trailerPickupZ\": -4560.52,\"startEngineDamage\": 0,\"startTransmissionDamage\": 0,\"startCabinDamage\": 0,\"startChassisDamage\": 0,\"startWheelDamage\": 0,\"finishEngineDamage\": 0.0138086,\"finishTransmissionDamage\": 0.00829076,\"finishCabinDamage\": 0.0220714,\"finishChassisDamage\": 0.0275892,\"finishWheelDamage\": 0.00427838,\"totalEngineDamage\": 0.0138086,\"totalTransmissionDamage\": 0.00829076,\"totalCabinDamage\": 0.0220714,\"totalChassisDamage\": 0.0275892,\"totalWheelDamage\": 0.00427838,\"totalTrailerDamage\": 0.0201135,\"osEnvironment\": \"Windows\",\"architecture\": \"x64\",\"steamID\": \"xxx\",\"steamUsername\": \"xxx\",\"navigationDistanceRemaining\": 160.393,\"teleported\": true}}";



    unsigned char a[KEY_SIZE+1];
    unsigned char b[IV_SIZE + 1];


    for (int i = 0; i < KEY_SIZE; i++)
        a[i] = 'a';
    for (int i = 0; i < IV_SIZE; i++)
        b[i] = 'b';
    a[KEY_SIZE] = '\0';
    b[IV_SIZE] = '\0';


    int predicted_len = strlen(data.c_str()) + (BLOCK_SIZE - (strlen(data.c_str()) % BLOCK_SIZE));
    predicted_len = strlen(data.c_str());
    unsigned char* encrypted = new unsigned char[predicted_len+1];
    std::string hex2 = NewMessage::StrToHex(a);
    std::string hex3 = NewMessage::StrToHex(b);
    //int encrypted_len = NewMessage::encryptcbc((unsigned char*)data.c_str(), strlen(data.c_str()), a, b, encrypted);
    int encrypted_len = NewMessage::encrypt((unsigned char*)data.c_str()+'\0', strlen(data.c_str()), a,b, encrypted);

    encrypted[predicted_len] = '\0';
    std::string hex = NewMessage::StrToHex(encrypted);

    std::cout << std::endl << std::endl << std::endl << std::endl;
    std::cout << hex << std::endl;
    std::cout << std::endl << std::endl << std::endl << std::endl;
    std::cout << hex2;
    std::cout << std::endl << std::endl << std::endl << std::endl;
    std::cout << hex3;
    std::cout << std::endl << std::endl << std::endl << std::endl;

    data.clear();
    //delete[] encrypted;
    /*----------------------------------------------------------------------*/
    data = "";

    curl_global_cleanup();
    /* Remove error strings */

    ERR_free_strings();
    return 0;
}

加密功能：

    int encrypt(unsigned char* plaintext, int plaintext_len,  unsigned char* key, unsigned char* iv, unsigned char* ciphertext)
    {
        EVP_CIPHER_CTX* ctx = NULL;
        int len = 0, ciphertext_len = 0;

        /* Create and initialise the context */
        if (!(ctx = EVP_CIPHER_CTX_new())) handleErrors();

        /* Initialise the encryption operation. */
        if (1 != EVP_EncryptInit_ex(ctx, EVP_aes_256_ctr(), NULL, key, iv))
            handleErrors();


        if (plaintext)
        {
            if (1 != EVP_EncryptUpdate(ctx, ciphertext, &len, plaintext, plaintext_len))
                handleErrors();

            ciphertext_len = len;
        }

        if (1 != EVP_EncryptFinal_ex(ctx, ciphertext + len, &len)) handleErrors();
        ciphertext_len += len;

        EVP_CIPHER_CTX_free(ctx);

        return ciphertext_len;
    }

我不知道为什么data即使 ciphertext_len 返回正确的值也不会完全加密。如果有人能指出我正确的方向，那就太好了。

标签： encryptionvisual-c++openssl

Answer 1

我让它成功运行，另一位 c++ 开发人员帮助我解决了我正在使用的 StrToHex 方法的问题。有问题的方法（固定）发布在下面：

std::string StrToHex(const std::string& in)
        {
            std::string csHexString;
            for (unsigned int i = 0; i < in.size(); i++)
            {
                char tmp[10];
                int len = sprintf(tmp, "%02X", (in[i] & 0xFF));
                csHexString += std::string(tmp, len);
            }
            return csHexString;
        }