一般是对用户密码及一些重要信息加密，防止泄露。

 

/// <summary>

/// MD5加密

/// </summary>

/// <param name="input">需要加密的字符串</param>

/// <returns></returns>

public static string MD5Encrypt(string input)

{

return MD5Encrypt(input, new UTF8Encoding());

}

/// <summary>

/// MD5加密

/// </summary>

/// <param name="input">需要加密的字符串</param>

/// <param name="encode">字符的编码</param>

/// <returns></returns>

public static string MD5Encrypt(string input, Encoding encode)

{

MD5 md5 = new MD5CryptoServiceProvider();

byte[] t = md5.ComputeHash(encode.GetBytes(input));

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();

}

/// <summary>

/// MD5对文件流加密

/// </summary>

/// <param name="sr"></param>

/// <returns></returns>

public static string MD5Encrypt(Stream stream)

{

MD5 md5serv = MD5CryptoServiceProvider.Create();

byte[] buffer = md5serv.ComputeHash(stream);

StringBuilder sb = new StringBuilder();

foreach (byte var in buffer)

sb.Append(var.ToString("x2"));

return sb.ToString();

}

/// <summary>

/// MD5加密(返回16位加密串)

/// </summary>

/// <param name="input"></param>

/// <param name="encode"></param>

/// <returns></returns>

public static string MD5Encrypt16(string input, Encoding encode)

{

MD5CryptoServiceProvider md5 = new MD5CryptoServiceProvider();

string result = BitConverter.ToString(md5.ComputeHash(encode.GetBytes(input)), 4, 8);

result = result.Replace("-", "");

return result;

}