java rsa 解密用PKCS8 格式报java.security.spec.InvalidKeySpecException: Only RSAPublicKeySpec and X509Encod

Exception in thread "main" java.security.spec.InvalidKeySpecException: Only RSAPublicKeySpec and X509EncodedKeySpec supported for RSA public keys
    at sun.security.rsa.RSAKeyFactory.generatePublic(RSAKeyFactory.java:306)
    at sun.security.rsa.RSAKeyFactory.engineGeneratePublic(RSAKeyFactory.java:201)
    at java.security.KeyFactory.generatePublic(KeyFactory.java:334)
    at com.asymmetric.rsa.TestRSA.testDecrypt(TestRSA.java:77)
    at com.asymmetric.rsa.TestRSA.main(TestRSA.java:32)

一直不明白,为什么不能用PKCS8EncodedKeySpec 作RSA解密的格式,今天就尝试了一下,报错很明显是java底层 RSA公钥只支持X509EncodedKeySpec这种格式

测试代码:

package com.asymmetric.rsa;

import java.security.InvalidKeyException;
import java.security.Key;
import java.security.KeyFactory;
import java.security.NoSuchAlgorithmException;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.Base64;

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;



public class TestRSA {
    
    public static String publicKey = "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDQgEoj3z9JrdPNI23DbMQkl3gkGuDke7iBr5yrYyqolkTyxuBLWFwHNuGv4VKOj9fXg61QxpaJ/fxDBvMvmkBSRowHBloGFceVTx8wV/8u0DcjvTCu0IZ1zp6wjG6xBn5j66Sg/q+9hvaY2p7fkKmsvcW6VoNPgQHU1Cf01DLZmQIDAQAB+oXcINOiE3AsuZ4VJmwNZg9Y/7fY+OFRS2JAh5YMsrv2qyoGP+Z9ksre26NYR+Lt91B2lhdwJHLpQpziaANZm/ONb31fj/lwIDAQAB";
    public static String privateKey = "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";
    
    private static String algorithm = "RSA"; //$NON-NLS-1$
    
    private static String data = "这是一个test"; //$NON-NLS-1$
    
    public static void main(String[] args) throws NoSuchAlgorithmException, InvalidKeySpecException, NoSuchPaddingException, IllegalBlockSizeException, BadPaddingException, InvalidKeyException {
        byte[] test = testEncrypt(privateKey,data);
        String testDecrypt = testDecrypt(publicKey, test);
        System.out.println(testDecrypt);
    }
    

    /**
     * 加密
     * @param key
     * @param data
     * @return
     * @throws NoSuchAlgorithmException
     * @throws InvalidKeySpecException
     * @throws NoSuchPaddingException
     * @throws IllegalBlockSizeException
     * @throws BadPaddingException
     * @throws InvalidKeyException
     */
    public static byte[] testEncrypt(String key,String data) throws NoSuchAlgorithmException, InvalidKeySpecException, NoSuchPaddingException, IllegalBlockSizeException, BadPaddingException, InvalidKeyException{
        byte[] decode = Base64.getDecoder().decode(key);
        PKCS8EncodedKeySpec pkcs8EncodedKeySpec = new PKCS8EncodedKeySpec(decode);
        KeyFactory kf = KeyFactory.getInstance(algorithm);
        PrivateKey generatePrivate = kf.generatePrivate(pkcs8EncodedKeySpec);
        Cipher ci = Cipher.getInstance(algorithm);
        ci.init(1, generatePrivate);
        byte[] doFinal = ci.doFinal(data.getBytes());
//        return Base64.getEncoder().encodeToString(doFinal);
        return doFinal;
    }

    
    /**
     * 解密
     * @param key
     * @param data
     * @return
     * @throws NoSuchAlgorithmException
     * @throws InvalidKeyException 
     * @throws NoSuchPaddingException 
     * @throws InvalidKeySpecException 
     * @throws BadPaddingException 
     * @throws IllegalBlockSizeException 
     */
    public static String testDecrypt(String key,byte[] data) throws NoSuchAlgorithmException, InvalidKeyException, NoSuchPaddingException, InvalidKeySpecException, IllegalBlockSizeException, BadPaddingException{
        byte[] decode = Base64.getDecoder().decode(key);
        PKCS8EncodedKeySpec pkcs8EncodedKeySpec = new PKCS8EncodedKeySpec(decode); //java底层 RSA公钥只支持X509EncodedKeySpec这种格式
        //X509EncodedKeySpec x509EncodedKeySpec = new X509EncodedKeySpec(decode);
        KeyFactory kf = KeyFactory.getInstance(algorithm);
        PublicKey generatePublic = kf.generatePublic(pkcs8EncodedKeySpec);
        Cipher ci = Cipher.getInstance(algorithm);
        ci.init(1,generatePublic);
//        byte[] doFinal = ci.doFinal(Base64.getDecoder().decode(data));
        byte[] doFinal = ci.doFinal(Base64.getDecoder().decode(data));
        return Base64.getEncoder().encodeToString(doFinal);
    }
    
}

解决方法:

将解密时的PKCS8EncodedKeySpec  转换成X509EncodedKeySpec  就可以了,其实rsa公钥也支持RSAPublicKeySpec 但是构造方法不同,没有直接传入字节数组的构造