C＃RSA实现 - 加密和解密字符串

Question

我需要在C＃中实现简单的RSA程序，它将加密和解密字符串（我只找到了整数而不是字符串的工作示例）。这就是我所拥有的：

public static BigInteger euklides(BigInteger e, BigInteger phi)
    {

        BigInteger x = BigInteger.Zero;
        BigInteger y = BigInteger.One;
        BigInteger lastx = BigInteger.One;
        BigInteger lasty = BigInteger.Zero;
        BigInteger temp;
        BigInteger phiOriginal = phi;

        while (!phi.Equals(BigInteger.Zero))
        {
            BigInteger q = BigInteger.Divide(e, phi);
            BigInteger r = e % phi;

            e = phi;
            phi = r;

            temp = x;
            x = BigInteger.Subtract(lastx, BigInteger.Multiply(q, x));
            lastx = temp;

            temp = y;
            y = BigInteger.Subtract(lasty, BigInteger.Multiply(q, y)); 
            lasty = temp;
        }
        if (lastx.CompareTo(BigInteger.Zero) > 0)
            return lastx;
        else
            return BigInteger.Subtract(phiOriginal, BigInteger.Negate(lastx));
    }

    static void Main(string[] args)
    {
        string p = "7980724731397402975742029729905308770673214017611336839039040369204140805514764089662732987804985392082433047940750616286743290036112256089536100737587703";
        string q = "11740715087896814955393784459915361965809210593358905908497824655235476226804879681331854108325808626683143689269719764318983014066100961329905775841321093";

        //Convert string to BigInteger
        BigInteger rsa_p = BigInteger.Parse(p);
        BigInteger rsa_q = BigInteger.Parse(q);

        BigInteger rsa_n = BigInteger.Multiply(rsa_p, rsa_q);

        BigInteger rsa_fn = BigInteger.Multiply((rsa_p - 1), (rsa_q - 1));

        BigInteger rsa_e = 13;

        BigInteger rsa_d = euklides(rsa_e, rsa_fn);


        string message = "hellojs";
        byte[] buffer2 = Encoding.ASCII.GetBytes(message);
        BigInteger m = new BigInteger(buffer2);
        BigInteger C = BigInteger.ModPow(m, rsa_e, rsa_n);
        Console.WriteLine("Encrypted: " + Convert.ToBase64String(C.ToByteArray()));

        BigInteger M = BigInteger.ModPow(C, rsa_d, rsa_n);

        byte[] decoded2 = M.ToByteArray();

        if (decoded2[0] == 0)
        {
            decoded2 = decoded2.Where(b => b != 0).ToArray();
        }
        string message3 = ASCIIEncoding.ASCII.GetString(decoded2);


        Console.WriteLine("Decrypted: " + message3);

        Console.ReadKey();
    }

我的问题是解密 - 我得到一些随机不可读的字符。在加密之前将字符串转换为BigInteger并且在解密之后将BigInteger转换为字符串似乎有问题。有谁知道如何解决它？谢谢:)）

编辑：

对于硬编码的值，程序不起作用。但对于另一个值，如： p 895493730028043880424493947156310024783769570419237367312822281990143938858343133550073770770223036789276483743805430421717817291115136285741935009393873829

q 11326960495280396859963951277476202902476795535605385467047045654941363025487995731611833231534039530362375614741751500907989679189162164468639573092827123

它现在正在运作。我不明白为什么：）