using System.Security.Cryptography;

// 將傳入的字串加密。
// 由呼叫端應用程式傳來的參數(strEcrypt)，選擇要使用的加密演算法，如: MD5、SHA1…等
public string RunEncrypt(string strOriginal, string strEcrypt)
{
    HashAlgorithm algorithm = null;
    string strHashed = string.Empty;
    byte[] byteData = null;

    switch (strEcrypt)
    {
        case "MD5":
            algorithm = new MD5CryptoServiceProvider();     // 使用 MD5 演算法做加密
            break;
        case "RIPEMD160":
            algorithm = new RIPEMD160Managed();
            break;
        case "SHA1":
            algorithm = new SHA1Managed();
            break;
        case "SHA256":
            algorithm = new SHA256Managed();
            break;
        case "SHA384":
            algorithm = new SHA384Managed();
            break;
        case "SHA512":
            algorithm = new SHA512Managed();
            break;
        default:
            algorithm = new MD5CryptoServiceProvider();
            break;
    }


    if (!string.IsNullOrEmpty(strOriginal))
    {
        byteData = algorithm.ComputeHash(Encoding.ASCII.GetBytes(strOriginal));
        strHashed = Encoding.ASCII.GetString(byteData);
    }

    return strHashed;
}