c# md5加密算法实例

/// <summary>
/// 获得MD5加密字符串
/// </summary>
/// <param name="s">源字符串</param>
/// <returns>目标字符串</returns>
public static String MD5(String s)
{
char[] hexDigits = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F' };
try
{
byte[] btInput = System.Text.Encoding.UTF8.GetBytes(s);
// 获得MD5摘要算法的 MessageDigest 对象
MD5 mdInst = System.Security.Cryptography.MD5.Create();
// 使用指定的字节更新摘要
mdInst.ComputeHash(btInput);
// 获得密文
byte[] md = mdInst.Hash;
// 把密文转换成十六进制的字符串形式
int j = md.Length;
char[] str = new char[j * 2];
int k = 0;
for (int i = 0; i < j; i++)
{
byte byte0 = md[i];
str[k++] = hexDigits[(int)(((byte)byte0) >> 4) & 0xf];
str[k++] = hexDigits[byte0 & 0xf];
}
return new string(str);
}
catch
{
// Console.Error.WriteLine(e.StackTrace);
return null;
}
}

/// <summary>
/// MD5　32位加密
/// </summary>
/// <param name="str"></param>
/// <returns></returns>
public static String md532(String s)
{
MD5 md5 = new MD5CryptoServiceProvider();
byte[] bytes = System.Text.Encoding.UTF8.GetBytes(s);
bytes = md5.ComputeHash(bytes);
md5.Clear();

string ret = "";
for (int i = 0; i < bytes.Length; i++)
{
ret += Convert.ToString(bytes[i], 16).PadLeft(2, '0');
}

return ret.PadLeft(32, '0');
}

/// <summary>
/// ASP MD5加密算法
/// </summary>
/// <param name="md5str">要加密的字符串</param>
/// <param name="type">16还是32位加密</param>
/// <returns>Asp md5加密结果</returns>
public static string GetMd5(string md5str, int type)
{
if (type == 16)
{
MD5 algorithm = MD5.Create();
byte[] data = algorithm.ComputeHash(Encoding.UTF8.GetBytes(md5str));
string sh1 = "";
for (int i = 0; i < data.Length; i++)
{
sh1 += data[i].ToString("x2").ToUpperInvariant();
}
return sh1.Substring(8, 16).ToLower();
}
else if (type == 32)
{
MD5 algorithm = MD5.Create();
byte[] data = algorithm.ComputeHash(Encoding.UTF8.GetBytes(md5str));
string sh1 = "";
for (int i = 0; i < data.Length; i++)
{
sh1 += data[i].ToString("x2").ToUpperInvariant();
}
return sh1.ToLower();
}
return "";
}