java - RSA 与 AES 加密和解密

Question

我的 RSA 解密有什么问题？

这是加密代码:

    try {
        //Get the public key from the keyStore and set up the Cipher object
        PublicKey publicKey = getPubKey(keyStore,keyName);
        Cipher rsaCipher = Cipher.getInstance("RSA");
        rsaCipher.init(Cipher.ENCRYPT_MODE, publicKey);

        //Read the plainText
        System.out.println("Loading plaintext file: "+inFile); 
        RandomAccessFile rawDataFromFile = new RandomAccessFile(inFile, "r");
        byte[] plainText = new byte[(int)rawDataFromFile.length()];
        rawDataFromFile.read(plainText);

        // Generate a symmetric key to encrypt the data and initiate the AES Cipher Object
        System.out.println("Generating AES key"); 
        KeyGenerator sKenGen = KeyGenerator.getInstance("AES"); 
        Key aesKey = sKenGen.generateKey();
        Cipher aesCipher = Cipher.getInstance("AES");
        aesCipher.init(Cipher.ENCRYPT_MODE, aesKey);

        // Encrypt the symmetric AES key with the public RSA key
        System.out.println("Encrypting Data"); 
        byte[] encodedKey = rsaCipher.doFinal(aesKey.getEncoded()); 
        // Encrypt the plaintext with the AES key
        byte[] cipherText = aesCipher.doFinal(plainText);

        //Write the encrypted AES key and Ciphertext to the file.
        System.out.println("Writting to file: "+outFile);
        FileOutputStream outToFile = new FileOutputStream(outFile);
        outToFile.write(encodedKey);
        outToFile.write(cipherText);

        System.out.println("Closing Files");
        rawDataFromFile.close();
        outToFile.close();
    }
    catch (Exception e) { 
        System.out.println("Doh: "+e); 
    }

这是我的解密代码，我认为它会很好地工作，但事实并非如此。任何人都可以帮助我吗？

它一直有错误:javax.crypto.BadPaddingException:解密错误

不知道该怎么办，有人可以给我一些建议吗？

private static void decryptRSA() {
    try {
        System.out.println("Loading plaintext file: "+inFile); 
        RandomAccessFile rawDataFromFile = new RandomAccessFile(inFile, "r");
        byte[] cipherText = new byte[(int)rawDataFromFile.length()];
        byte encodedkey[] = new byte[256];
        rawDataFromFile.read(encodedkey, 0, 256);
        rawDataFromFile.read(cipherText);

        PublicKey publicKey = getPubKey(keyStore,keyName);
        Cipher rsaCipher = Cipher.getInstance("RSA");
        rsaCipher.init(Cipher.DECRYPT_MODE, publicKey);

        byte[] aeskey = rsaCipher.doFinal(encodedkey);
        SecretKeySpec aesKey = new SecretKeySpec(aeskey, "AES");
        Cipher aesCipher = Cipher.getInstance("AES");
        aesCipher.init(Cipher.DECRYPT_MODE, aesKey);

        byte[] plainText = aesCipher.doFinal(cipherText);

        System.out.println("Writting to file: "+outFile);
        FileOutputStream outToFile = new FileOutputStream(outFile);
        outToFile.write(plainText);
        System.out.println("Closing Files");
        rawDataFromFile.close();
        outToFile.close();
    }
    catch (Exception e) { 
        System.out.println("Doh: "+e); 
    }
}

Answer 1

1. RSA 解密是使用私钥而不是公钥完成的。

2. 解密代码中cipherText数组的长度不正确。您应该减去 256，或者将实际读取长度传递给 Cipher.doFinal()，或者实际上两者都传递。

注意，尽管您正在打印消息，但您的解密步骤实际上是从密文文件中读取，而不是从明文文件中读取。