C#常用字符串加密解密方法封装代码

//方法二(可逆加密解密)：
//using System.Security.Cryptography;
public string Encode(string data)
{
    byte[] byKey = System.Text.ASCIIEncoding.ASCII.GetBytes(KEY_64);
    byte[] byIV = System.Text.ASCIIEncoding.ASCII.GetBytes(IV_64);
    DESCryptoServiceProvider cryptoProvider = new DESCryptoServiceProvider();
    int i = cryptoProvider.KeySize;
    MemoryStream ms = new MemoryStream();
    CryptoStream cst = new CryptoStream(ms, cryptoProvider.CreateEncryptor(byKey, byIV), CryptoStreamMode.Write);
    StreamWriter sw = new StreamWriter(cst);
    sw.Write(data);
    sw.Flush();
    cst.FlushFinalBlock();
    sw.Flush();
    return Convert.ToBase64String(ms.GetBuffer(), 0, (int)ms.Length);
}
public string Decode(string data)
{
    byte[] byKey = System.Text.ASCIIEncoding.ASCII.GetBytes(KEY_64);
    byte[] byIV = System.Text.ASCIIEncoding.ASCII.GetBytes(IV_64);
    byte[] byEnc;
    try
    {
        byEnc = Convert.FromBase64String(data);
    }
    catch
    {
        return null;
    }
    DESCryptoServiceProvider cryptoProvider = new DESCryptoServiceProvider();
    MemoryStream ms = new MemoryStream(byEnc);
    CryptoStream cst = new CryptoStream(ms, cryptoProvider.CreateDecryptor(byKey, byIV), CryptoStreamMode.Read);
    StreamReader sr = new StreamReader(cst);

//方法三(MD5不可逆)：
//using System.Security.Cryptography;
//MD5不可逆加密
//32位加密
public string GetMD5_32(string s, string _input_charset)
{
    MD5 md5 = new MD5CryptoServiceProvider();
    byte[] t = md5.ComputeHash(Encoding.GetEncoding(_input_charset).GetBytes(s));
    StringBuilder sb = new StringBuilder(32);
    for (int i = 0; i < t.Length; i++)
    {
        sb.Append(t[i].ToString("x").PadLeft(2, '0'));
    }
    return sb.ToString();
}
//16位加密
public static string GetMd5_16(string ConvertString)
{
    MD5CryptoServiceProvider md5 = new MD5CryptoServiceProvider();
    string t2 = BitConverter.ToString(md5.ComputeHash(UTF8Encoding.Default.GetBytes(ConvertString)), 4, 8);
    t2 = t2.Replace("-", "");
    return t2;
}

//方法四(对称加密)：
//using System.IO;
//using System.Security.Cryptography;
private SymmetricAlgorithm mobjCryptoService;
private string Key;
/// <summary>  
/// 对称加密类的构造函数  
/// </summary>  
public SymmetricMethod()
{
    mobjCryptoService = new RijndaelManaged();
    Key = "Guz(%&hj7x89H$yuBI0456FtmaT5&fvHUFCy76*h%(HilJ$lhj!y6&(*jkP87jH7";
}
/// <summary>  
/// 获得密钥  
/// </summary>  
/// <returns>密钥</returns>  
private byte[] GetLegalKey()
{
    string sTemp = Key;
    mobjCryptoService.GenerateKey();
    byte[] bytTemp = mobjCryptoService.Key;
    int KeyLength = bytTemp.Length;
    if (sTemp.Length > KeyLength)
        sTemp = sTemp.Substring(0, KeyLength);
    else if (sTemp.Length < KeyLength)
        sTemp = sTemp.PadRight(KeyLength, ' ');
    return ASCIIEncoding.ASCII.GetBytes(sTemp);
}
/// <summary>  
/// 获得初始向量IV  
/// </summary>  
/// <returns>初试向量IV</returns>  
private byte[] GetLegalIV()
{
    string sTemp = "E4ghj*Ghg7!rNIfb&95GUY86GfghUb#er57HBh(u%g6HJ($jhWk7&!hg4ui%$hjk";
    mobjCryptoService.GenerateIV();
    byte[] bytTemp = mobjCryptoService.IV;
    int IVLength = bytTemp.Length;
    if (sTemp.Length > IVLength)
        sTemp = sTemp.Substring(0, IVLength);
    else if (sTemp.Length < IVLength)
        sTemp = sTemp.PadRight(IVLength, ' ');
    return ASCIIEncoding.ASCII.GetBytes(sTemp);
}
/// <summary>  
/// 加密方法  
/// </summary>  
/// <param name="Source">待加密的串</param>  
/// <returns>经过加密的串</returns>  
public string Encrypto(string Source)
{
    byte[] bytIn = UTF8Encoding.UTF8.GetBytes(Source);
    MemoryStream ms = new MemoryStream();
    mobjCryptoService.Key = GetLegalKey();
    mobjCryptoService.IV = GetLegalIV();
    ICryptoTransform encrypto = mobjCryptoService.CreateEncryptor();
    CryptoStream cs = new CryptoStream(ms, encrypto, CryptoStreamMode.Write);
    cs.Write(bytIn, 0, bytIn.Length);
    cs.FlushFinalBlock();
    ms.Close();
    byte[] bytOut = ms.ToArray();
    return Convert.ToBase64String(bytOut);
}
/// <summary>  
/// 解密方法  
/// </summary>  
/// <param name="Source">待解密的串</param>  
/// <returns>经过解密的串</returns>  
public string Decrypto(string Source)
{
    byte[] bytIn = Convert.FromBase64String(Source);
    MemoryStream ms = new MemoryStream(bytIn, 0, bytIn.Length);
    mobjCryptoService.Key = GetLegalKey();
    mobjCryptoService.IV = GetLegalIV();
    ICryptoTransform encrypto = mobjCryptoService.CreateDecryptor();
    CryptoStream cs = new CryptoStream(ms, encrypto, CryptoStreamMode.Read);
    StreamReader sr = new StreamReader(cs);
    return sr.ReadToEnd();
}

//方法五：
//using System.IO;
//using System.Security.Cryptography;
//using System.Text;
//默认密钥向量
private static byte[] Keys = { 0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF };
/**//**//**//// <summary>
/// DES加密字符串 keleyi.com
/// </