MD5密钥的加密，解密 生成密钥

/// <summary>
/// 加密
/// </summary>
/// <param name="toEncrypt">要加密的字符串，即明文</param>
/// <param name="key">公共密钥</param>
/// <param name="useHashing">是否使用MD5生成机密秘钥</param>
/// <returns>加密后的字符串，即密文</returns>
public static string Encrypt(string toEncrypt, string key, bool useHashing)
{
try
{
byte[] keyArray;
byte[] toEncryptArray = UTF8Encoding.UTF8.GetBytes(toEncrypt);

if (useHashing)
{
MD5CryptoServiceProvider hashmd5 = new MD5CryptoServiceProvider();
keyArray = hashmd5.ComputeHash(UTF8Encoding.UTF8.GetBytes(key));
}
else
keyArray = UTF8Encoding.UTF8.GetBytes(key);

TripleDESCryptoServiceProvider tdes = new TripleDESCryptoServiceProvider();

tdes.Key = keyArray;
tdes.Mode = CipherMode.ECB;
tdes.Padding = PaddingMode.PKCS7;

ICryptoTransform cTransform = tdes.CreateEncryptor();
byte[] resultArray = cTransform.TransformFinalBlock(toEncryptArray, 0, toEncryptArray.Length);

return Convert.ToBase64String(resultArray, 0, resultArray.Length);
}
catch
{

}
return string.Empty;
}

/// <summary>
/// 解密
/// </summary>
/// <param name="toDecrypt">要解密的字符串，即密文</param>
/// <param name="key">公共密钥</param>
/// <param name="useHashing">是否使用MD5生成机密密钥</param>
/// <returns>解密后的字符串，即明文</returns>
public static string Decrypt(string toDecrypt, string key, bool useHashing)
{
try
{
byte[] keyArray;
byte[] toEncryptArray = Convert.FromBase64String(toDecrypt);

if (useHashing)
{
MD5CryptoServiceProvider hashmd5 = new MD5CryptoServiceProvider();
keyArray = hashmd5.ComputeHash(UTF8Encoding.UTF8.GetBytes(key));
}
else
keyArray = UTF8Encoding.UTF8.GetBytes(key);

TripleDESCryptoServiceProvider tdes = new TripleDESCryptoServiceProvider();
tdes.Key = keyArray;
tdes.Mode = CipherMode.ECB;
tdes.Padding = PaddingMode.PKCS7;

ICryptoTransform cTransform = tdes.CreateDecryptor();
byte[] resultArray = cTransform.TransformFinalBlock(toEncryptArray, 0, toEncryptArray.Length);

return UTF8Encoding.UTF8.GetString(resultArray);

}
catch
{

}
return string.Empty;

}