Question

这是我的代码块，我假设Decrypt方法不起作用，它返回一些垃圾值。我是新手。

public string Encrypt(string toEncrypt, string key, bool useHashing)
{
    byte[] keyArray;
    byte[] toEncryptArray = UTF8Encoding.UTF8.GetBytes(toEncrypt);

    if (useHashing)
    {
        MD5CryptoServiceProvider hashmd5 = new MD5CryptoServiceProvider();
        keyArray = hashmd5.ComputeHash(UTF8Encoding.UTF8.GetBytes(key));
    }
    else
        keyArray = UTF8Encoding.UTF8.GetBytes(key);

    TripleDESCryptoServiceProvider tdes = new TripleDESCryptoServiceProvider();
    tdes.Key = keyArray;
    tdes.Mode = CipherMode.CBC;
    tdes.Padding = PaddingMode.Zeros;
    ICryptoTransform cTransform = tdes.CreateEncryptor();
    byte[] resultArray = cTransform.TransformFinalBlock(toEncryptArray, 0, toEncryptArray.Length);

    return Convert.ToBase64String(resultArray, 0, resultArray.Length);
}

public string Decrypt(string toDecrypt, string key, bool useHashing)
{
    byte[] keyArray;
    byte[] toEncryptArray = Convert.FromBase64String(toDecrypt);

    if (useHashing)
    {
        MD5CryptoServiceProvider hashmd5 = new MD5CryptoServiceProvider();
        keyArray = hashmd5.ComputeHash(UTF8Encoding.UTF8.GetBytes(key));
    }
    else
        keyArray = UTF8Encoding.UTF8.GetBytes(key);

    TripleDESCryptoServiceProvider tdes = new TripleDESCryptoServiceProvider();
    tdes.Key = keyArray;
    tdes.Mode = CipherMode.CBC;
    tdes.Padding = PaddingMode.Zeros;

    ICryptoTransform cTransform = tdes.CreateDecryptor();
    byte[] resultArray = cTransform.TransformFinalBlock(toEncryptArray, 0, toEncryptArray.Length);

    return UTF8Encoding.UTF8.GetString(resultArray);
}



        String key = "ShHhd8a08JhJiho98ayslcjh";
    string tmp = "My Name Is Tanmoy Mitra";
    string encryptStr = Encrypt(tmp,key,false);
    Debug.Log("Encrypt Text:"+encryptStr);
    Debug.Log("Decrypt Text:"+Decrypt(encryptStr,key,false));

但它会返回��2�cU:EIs Tanmoy Mitra 它适用于//CipherMode.ECB模式，但我想知道为什么这种CBC模式在这种情况下不起作用。请帮我解决这个问题。

Answer 1

您没有指定IV（初始化向量）。加密和解密需要使用相同的IV。例如，一个坏的方式是：

tdes.IV = new byte[tdes.BlockSize / 8];

...加密和解密。更好的方法是在加密时生成一次随机IV（在创建加密服务提供程序时自动完成）并在解密时记住它。

来自IV property documentation（强调我的）：

派生自SymmetricAlgorithm类的类使用称为密码块链接（CBC）的链接模式，该模式需要密钥和初始化向量来对数据执行加密转换。 要解密使用其中一个SymmetricAlgorithm类加密的数据，必须将Key属性和IV属性设置为用于加密的相同值。

Answer 2

试试这个......

[Serializable]
public class CriptoEngine
{

    #region Variables

    private string key;
    byte[] keyArray;
    byte[] arrayDecypt;
    byte[] resultArray;
    byte[] arrayEncrypt;

    #endregion

    #region Metodos Publicos

    public CriptoEngine(string user)
    {
        key = user;
    }
    public TDecrypData SetEncriptar<TEncr, TDecrypData>(TEncr objEncrypt)
    {
        object tEncr;
        arrayEncrypt = UTF8Encoding.UTF8.GetBytes(Convert.ToString(objEncrypt));
        MD5CryptoServiceProvider hashmd5 = new MD5CryptoServiceProvider();
        keyArray = hashmd5.ComputeHash(UTF8Encoding.UTF8.GetBytes(key));
        hashmd5.Clear();
        TripleDESCryptoServiceProvider tdes = new TripleDESCryptoServiceProvider();
        tdes.Key = keyArray; tdes.Mode = CipherMode.ECB;
        tdes.Padding = PaddingMode.PKCS7;
        ICryptoTransform cTransform = tdes.CreateEncryptor();
        resultArray = cTransform.TransformFinalBlock(arrayEncrypt, 0, arrayEncrypt.Length);
        tdes.Clear();
        Type t = typeof(TDecrypData);
        switch (t.Name)
        {
            case "Byte[]":
                tEncr = resultArray;
                break;
            default:
                tEncr = Convert.ToBase64String(resultArray, 0, resultArray.Length);
                break;
        }            
        return (TDecrypData)tEncr;

    }

    public TEncryptData GetDescr<TDesc, TEncryptData>(TDesc objDecry)
    {
        arrayDecypt = Convert.FromBase64String(objDecry.ToString());
        MD5CryptoServiceProvider hashmd5 = new MD5CryptoServiceProvider();
        keyArray = hashmd5.ComputeHash(UTF8Encoding.UTF8.GetBytes(key));
        hashmd5.Clear();
        TripleDESCryptoServiceProvider tdes = new TripleDESCryptoServiceProvider();
        tdes.Key = keyArray;
        tdes.Mode = CipherMode.ECB;
        tdes.Padding = PaddingMode.PKCS7;
        ICryptoTransform cTransform = tdes.CreateDecryptor();
        resultArray = cTransform.TransformFinalBlock(arrayDecypt, 0, arrayDecypt.Length);
        tdes.Clear();
        object crypto = UTF8Encoding.UTF8.GetString(resultArray);
        return (TEncryptData)crypto;
    }

    #endregion
}

加密＆amp; C＃中的解密

2 个答案: