#region MD5算法
public string md5(string str, int code)
{
if (code == 32) //32位加密
{
return System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(str, "MD5").ToLower();
}
else //16位MD5加密（取32位加密的9~25字符）
{
return System.Web.Security.FormsAuthentication.HashPasswordForStoringInConfigFile(str, "MD5").ToLower().Substring(8, 16);
}
}
#endregion

#region DESEncrypt DES加密
// <summary>
/// 進行DES加密。
/// </summary>
/// <param name=”pToEncrypt”>要加密的字符串。</param>
/// <param name=”sKey”>密鑰，且必須為8位。</param>
/// <returns>以Base64格式返回的加密字符串。</returns>
public string DESEncrypt(string pToEncrypt, string sKey)
{
using (DESCryptoServiceProvider des = new DESCryptoServiceProvider())
{
byte[] inputByteArray = Encoding.UTF8.GetBytes(pToEncrypt);
des.Key = ASCIIEncoding.ASCII.GetBytes(sKey);
des.IV = ASCIIEncoding.ASCII.GetBytes(sKey);
System.IO.MemoryStream ms = new System.IO.MemoryStream();
using (CryptoStream cs = new CryptoStream(ms, des.CreateEncryptor(), CryptoStreamMode.Write))
{
cs.Write(inputByteArray, 0, inputByteArray.Length);
cs.FlushFinalBlock();
cs.Close();
}
string str = Convert.ToBase64String(ms.ToArray());
ms.Close();
return str;
}
}
#endregion

#region DESDecrypt DES解密
/// <summary>
/// 進行DES解密。
/// </summary>
/// <param name=”pToDecrypt”>要解密的以Base64</param>
/// <param name=”sKey”>密鑰，且必須為8位。</param>
/// <returns>已解密的字符串。</returns>
public string DESDecrypt(string pToDecrypt, string sKey)
{
byte[] inputByteArray = Convert.FromBase64String(pToDecrypt);
using (DESCryptoServiceProvider des = new DESCryptoServiceProvider())
{
des.Key = ASCIIEncoding.ASCII.GetBytes(sKey);
des.IV = ASCIIEncoding.ASCII.GetBytes(sKey);
System.IO.MemoryStream ms = new System.IO.MemoryStream();
using (CryptoStream cs = new CryptoStream(ms, des.CreateDecryptor(), CryptoStreamMode.Write))
{
cs.Write(inputByteArray, 0, inputByteArray.Length);
cs.FlushFinalBlock();
cs.Close();
}
string str = Encoding.UTF8.GetString(ms.ToArray());
ms.Close();
return str;
}
}
#endregion