如何将解密的 BigInteger 转换回字符串？

Question

我正在研究 RSA 加密，我可以正确地加密和解密 BigInteger。我遇到的问题是，在加密之前，我可以轻松地将 BigInteger 转换回原始字符串。但是，在加密然后解密字符串成功返回原始 BigInteger 后，转换生成的 BigInteger 不会给出原始字符串。以下是我使用的代码...

public static void main(String args[]) {
    int keySize = 2048;

    BigInteger prime1 = new BigInteger(keySize / 2, 100, new SecureRandom());
    BigInteger prime2 = new BigInteger(keySize / 2, 100, new SecureRandom());

    BigInteger n = prime1.multiply(prime2); 

    BigInteger totient = prime1.subtract(BigInteger.ONE).multiply(prime2.subtract(BigInteger.ONE));

    BigInteger e;
    do e = new BigInteger(totient.bitLength(), new SecureRandom());
    while (e.compareTo(BigInteger.ONE) <= 0 || e.compareTo(totient) >= 0 || !e.gcd(totient).equals(BigInteger.ONE));

    BigInteger d = e.modInverse(totient);



    String original = "Hello World!";

    //convert the string into a BigInteger and display
    BigInteger enc = new BigInteger(original.getBytes());
    System.out.println("Original: \t" + enc.toString());

    //convert the big integer to the string to display
    String originalString = new String(enc.toByteArray());
    System.out.println(originalString);

    enc = enc.modPow(e, n);

    //decrypt and display the BigInteger value
    BigInteger dec = enc;
    dec = dec.modPow(d, n);
    System.out.println("Result: \t\t" + dec.toString());

    //Convert the big integer back into a string to display
    String message = new String(enc.toByteArray());
    System.out.println(message);
}

我的结果如下

 Original:  22405534230753928650781647905
 Hello World!
 Result:    22405534230753928650781647905
 ���$lɋ�Xİ�d��������GJ�pu-;�Ei:�r�)��Uknԫ��m�!
 #N�l3����@�:�ƂE�ۧ���$M������V{��#C@I�md�!�

这个 BigInteger 没有像解密前那样转换回字符串是有原因的吗？在将大整数转换回字符串时我是否遗漏了什么？

Answer 1

这一行：

String message = new String(enc.toByteArray());

大概应该是：

String message = new String(dec.toByteArray());

如何将解密的 BigInteger 转换回字符串？

How to convert decrypted BigInteger back to string?

java

string

encryption

biginteger