Java不可靠的RSA加密/解密字符串

Question

我用Java中的RSA算法对字符串进行不可靠的加密和解密有一个非常烦人的问题。 它接缝只能在35％的时间内工作，我无法弄清楚为什么它有时会起作用，有时却不起作用。 这是我写的一些测试代码，试图验证加密/解密中的随机性。 它运行100圈，每次加密和解密相同的字符串并打印成功的次数：

    public static void main(String[] args) throws Exception {
    byte[] dataToEncrypt = "Hello World!".getBytes("UTF-16LE");
    byte[] cipherData = null;
    byte[] decryptedData;

    KeyPairGenerator kpg = KeyPairGenerator.getInstance("RSA");
    kpg.initialize(512);
    KeyPair kp = kpg.genKeyPair();
    Key publicKey = kp.getPublic();
    Key privateKey = kp.getPrivate();
    KeyFactory fact = KeyFactory.getInstance("RSA");

    RSAPublicKeySpec pub = (RSAPublicKeySpec) fact.getKeySpec(publicKey,
            RSAPublicKeySpec.class);

    RSAPublicKeySpec spec = new RSAPublicKeySpec(pub.getModulus(), pub
            .getPublicExponent());
    KeyFactory factory = KeyFactory.getInstance("RSA");

    PublicKey publicKeyRSA = factory.generatePublic(spec);
    Cipher cipher = Cipher.getInstance("RSA");

    int k = 0;
    for (int i = 0; i < 100; i++) {
        try {
            cipher.init(Cipher.ENCRYPT_MODE, publicKeyRSA);
            cipherData = cipher.doFinal(dataToEncrypt);
        } catch (Exception e1) {
            System.out.println("Encrypt error");
        }

        String s = new String(cipherData, "UTF-16LE");
        cipher.init(Cipher.DECRYPT_MODE, privateKey);

        try {
            decryptedData = cipher.doFinal(s.getBytes("UTF-16LE"));
            System.out.println("Decrypted: "
                    + new String(decryptedData, "UTF-16LE"));
            k += 1;
        } catch (Exception e1) {
            System.out.println("Decrypt error");
        }
    }
    System.out.println("Number of correct decryptions is: " + k);

}

我试图用各种值初始化KeyPairGenerator但没有成功。

编辑：现在它就像魅力一样，感谢Base64 ：

    import java.io.FileOutputStream;
    import java.io.OutputStream;
    import java.security.Key;
    import java.security.KeyFactory;
    import java.security.KeyPair;
    import java.security.KeyPairGenerator;
    import java.security.PublicKey;
    import java.security.spec.RSAPublicKeySpec;
    import javax.crypto.Cipher;

    public class Test {

    public static void main(String[] args) throws Exception {
    byte[] dataToEncrypt = "Hello World!".getBytes("UTF-16LE");
    byte[] cipherData = null;
    byte[] decryptedData;


    KeyPairGenerator kpg = KeyPairGenerator.getInstance("RSA");
    kpg.initialize(512);
    KeyPair kp = kpg.genKeyPair();
    Key publicKey = kp.getPublic();
    Key privateKey = kp.getPrivate();
    KeyFactory fact = KeyFactory.getInstance("RSA");

    RSAPublicKeySpec pub = (RSAPublicKeySpec) fact.getKeySpec(publicKey,
            RSAPublicKeySpec.class);

    RSAPublicKeySpec spec = new RSAPublicKeySpec(pub.getModulus(), pub
            .getPublicExponent());
    KeyFactory factory = KeyFactory.getInstance("RSA");

    PublicKey publicKeyRSA = factory.generatePublic(spec);
    Cipher cipher = Cipher.getInstance("RSA");

    int k = 0;
    for (int i = 0; i < 100; i++) {
        try {
            cipher.init(Cipher.ENCRYPT_MODE, publicKeyRSA);
            cipherData = cipher.doFinal(dataToEncrypt);
        } catch (Exception e1) {
            System.out.println("Encrypt error");
        }

        String s = Base64.encodeBytes(cipherData);
        cipher.init(Cipher.DECRYPT_MODE, privateKey);

        try {
            decryptedData = cipher.doFinal(Base64.decode(s));
            System.out.println("Decrypted: "
                    + new String(decryptedData, "UTF-16LE"));
            k += 1;
        } catch (Exception e1) {
            System.out.println("Decrypt error");
        }
    }
    System.out.println("Number of correct decryptions is: " + k);

}

}

Answer 1

这是问题，或者至少是一个问题：

String s = new String(cipherData, "UTF-16LE");

你正在使用任意二进制数据并尝试从中创建一个字符串，将其视为UTF-16编码的文本。 不是。 这是任意的二进制数据。

要么保持二进制形式（如byte[] ），要么使用base64以安全，可逆的方式将其转换为文本。 （例如， 此公共域base64编码器具有合理的API。）

Answer 2

可能是因为您将加密的字节流转换为UTF16-LE，这是您不应该做的。