MD5、SHA1、DES加密和解密，Base64编码解码

/// <summary>
/// EncryptHelper 来自 www.Admin10000.com
/// </summary>
public class EncryptHelper
{
// 提供8个字符作为DES密钥（程序自动截取前8个字符）
private static string key = "admin10000.com";

/// <summary>
/// DES对称加密解密的密钥
/// </summary>
public static string Key
{
get
{
return key;
}
set
{
key = value;
}
}

/// <summary>
/// MD5 加密（不可逆加密）
/// </summary>
/// <param name="pass">要加密的原始字串</param>
/// <returns></returns>
public static string MD5Encrypt(string pass)
{
System.Security.Cryptography.MD5 md5 = newSystem.Security.Cryptography.MD5CryptoServiceProvider();
byte[] bytResult =md5.ComputeHash(System.Text.Encoding.UTF8.GetBytes(pass));
md5.Clear();
string strResult = BitConverter.ToString(bytResult);
strResult = strResult.Replace("-", "");
return strResult;
/* 另一种方法
pass = FormsAuthentication.HashPasswordForStoringInConfigFile(pass, "MD5");
return pass;
*/
}

/// <summary>
/// SHA1 加密（不可逆加密）
/// </summary>
/// <param name="pass">要加密的原始字串</param>
/// <returns></returns>
public static string SHA1Encrypt(string pass)
{
System.Security.Cryptography.SHA1 sha1 = newSystem.Security.Cryptography.SHA1CryptoServiceProvider();
byte[] bytResult =sha1.ComputeHash(System.Text.Encoding.UTF8.GetBytes(pass));
sha1.Clear();
string strResult = BitConverter.ToString(bytResult);
strResult = strResult.Replace("-", "");
return strResult;
/* 另一种方法
pass = FormsAuthentication.HashPasswordForStoringInConfigFile(pass, "SHA1");
return pass;
*/
}

/// <summary>
/// DES加密字符串
/// </summary>
/// <param name="encryptString">待加密的字符串</param>
/// <returns>加密成功返回加密后的字符串，失败返回源串</returns>
public static string DESEncrypt(string encryptString)
{
try
{
byte[] rgbKey = Encoding.UTF8.GetBytes(key.Substring(0, 8));
byte[] rgbIV = rgbKey;
byte[] inputByteArray = Encoding.UTF8.GetBytes(encryptString);
DESCryptoServiceProvider dCSP = new DESCryptoServiceProvider();
MemoryStream mStream = new MemoryStream();
CryptoStream cStream = new CryptoStream(mStream, dCSP.CreateEncryptor(rgbKey, rgbIV), CryptoStreamMode.Write);
cStream.Write(inputByteArray, 0, inputByteArray.Length);
cStream.FlushFinalBlock();
cStream.Close();
return Convert.ToBase64String(mStream.ToArray());
}
catch
{
return encryptString;
}
}

/// <summary>
/// DES解密字符串
/// </summary>
/// <param name="decryptString">待解密的字符串</param>
/// <returns>解密成功返回解密后的字符串，失败返源串</returns>
public static string DESDecrypt(string decryptString)
{
try
{
byte[] rgbKey = Encoding.UTF8.GetBytes(key.Substring(0, 8));
byte[] rgbIV = rgbKey;
byte[] inputByteArray = Convert.FromBase64String(decryptString);
DESCryptoServiceProvider DCSP = new DESCryptoServiceProvider();
MemoryStream mStream = new MemoryStream();
CryptoStream cStream = new CryptoStream(mStream, DCSP.CreateDecryptor(rgbKey, rgbIV), CryptoStreamMode.Write);
cStream.Write(inputByteArray, 0, inputByteArray.Length);
cStream.FlushFinalBlock();
cStream.Close();
return Encoding.UTF8.GetString(mStream.ToArray());
}
catch
{
return decryptString;
}
}

/// <summary>
/// 将普通字符串编码为BASE64字串
/// </summary>
/// <param name="str">源字符串</param>
/// <returns></returns>
public static string Base64Encode(string str)
{
return Convert.ToBase64String(Encoding.UTF8.GetBytes(str));
}

/// <summary>
/// 解码BASE64字串
/// </summary>
/// <param name="str">Base64字串</param>
/// <returns></returns>
public static string Base64Decode(string base64Str)
{
return Encoding.UTF8.GetString(Convert.FromBase64String(base64Str));
}
}