Question

我正在尝试设置RSA加密，因此我可以为自己创建一个简单的库以供将来使用，而我无法使这个简单的代码正常工作。这是源代码：

package rsa.testing;

import java.security.KeyPair;
import java.security.KeyPairGenerator;

import javax.crypto.Cipher;

public class AloneTest
{
    public static void doTest()
    {
        try
        {
            KeyPairGenerator gen = KeyPairGenerator.getInstance("RSA");
            gen.initialize(2048);
            KeyPair pair = gen.genKeyPair();
            System.out.println("Public key: " + byteArrayToString(pair.getPublic().getEncoded()));
            System.out.println("Private key: " + byteArrayToString(pair.getPrivate().getEncoded()));

            Cipher encryptPublic = Cipher.getInstance("RSA");
            encryptPublic.init(Cipher.ENCRYPT_MODE, pair.getPublic());

            Cipher decryptPublic = Cipher.getInstance("RSA");
            decryptPublic.init(Cipher.DECRYPT_MODE, pair.getPublic());

            Cipher encryptPrivate = Cipher.getInstance("RSA");
            encryptPrivate.init(Cipher.ENCRYPT_MODE, pair.getPrivate());

            Cipher decryptPrivate = Cipher.getInstance("RSA");
            decryptPrivate.init(Cipher.DECRYPT_MODE, pair.getPrivate());

            System.out.println("All ciphers created.");
            System.out.println();

            String plainText = "Hello World!";
            System.out.println("Plain text: " + plainText);
            String encrypted = new String(encryptPrivate.doFinal(plainText.getBytes()));
            System.out.println("Encrypted: " + encrypted);
            String decrypted = new String(decryptPublic.doFinal(encrypted.getBytes()));
            System.out.println("Decrypted: " + decrypted);
        }
        catch (Exception e)
        {
            e.printStackTrace();
        }
    }

    private static String byteArrayToString(byte[] bytes)
    {
        String str = "";

        for (byte b : bytes)
        {
            str += b + " ";
        }

        return str.trim();
    }
}

And this the output (image because it doesn't let me copy the encrypted text).

有什么想法吗？

编辑：更改了以下内容：

String plainText = "Hello World!";
System.out.println("Plain text: " + plainText);
String encrypted = byteToBase64String(encryptPublic.doFinal(plainText.getBytes()));
System.out.println("Encrypted: " + encrypted);
String decrypted = byteToBase64String(decryptPublic.doFinal(encrypted.getBytes()));
System.out.println("Decrypted: " + decrypted);

用于将字节转换为Base64的方法：

private static String byteToBase64String(byte[] bytes)
{
    return Base64.getEncoder().encodeToString(bytes);
}

但是现在我收到此错误：

Plain text: Hello World!
Encrypted: dCTsYrQTDfNkRr6+nupWW4ntsmD69wrWS1TDvS3Uk1B6lCKkycegAb7wJgnXNolZ58dRXgbzEyCkeM/IbH0ruIEMfuhS5vrggo1s9+6MQN2hW1I4iElJfAdGKYQ8H9pFhAws+VQGetjwvJwUI9iWIi15721vc508/ks7rn4oQOk=
javax.crypto.IllegalBlockSizeException: Data must not be longer than 128 bytes
    at com.sun.crypto.provider.RSACipher.doFinal(RSACipher.java:344)
    at com.sun.crypto.provider.RSACipher.engineDoFinal(RSACipher.java:389)
    at javax.crypto.Cipher.doFinal(Cipher.java:2164)
    at rsa.testing.AloneTest.doTest(AloneTest.java:40)
    at rsa.testing.Main.main(Main.java:21)

我必须进行某种拆分吗？还是我做错了其他事情？

Answer 1

您缺少此信息：

使用公钥进行加密时，应使用私钥进行解密
还有
用私钥加密时，应该使用公钥解密

更新

例如使用私有密钥，然后尝试使用相同私有密钥解密，您将拥有 java.crypto.BadPaddingException

我无法共享证明这一点的代码，但是我使用以下方法进行了测试：

KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance("RSA");
keyPairGen.initialize(2048);
keyPair = keyPairGen.generateKeyPair();

在使用Cipher时，我使用了：

Cipher.getInstance("RSA/ECB/PKCS1Padding")

javax.crypto.BadPaddingException：使用Java RSA加密时的解密错误

1 个答案: