java 中使用RSA非對稱性加密解密

需要引入的jar包:bcprov-jdk15on-161.jar

下載地址:https://www.bouncycastle.org/latest_releases.html

 //公鑰加密
    public static String encrypt(String content, PublicKey publicKey) {
        try{
            Security.addProvider(new org.bouncycastle.jce.provider.BouncyCastleProvider());
            Cipher cipher = Cipher.getInstance("RSA/NONE/OAEPWITHSHA256AndMGF1Padding","BC");
//            Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");//java默認"RSA"="RSA/ECB/PKCS1Padding"
            cipher.init(Cipher.ENCRYPT_MODE, publicKey);
            byte[] output = cipher.doFinal(content.getBytes());
            BASE64Encoder encoder = new BASE64Encoder();
            return encoder.encode(output);
        }catch (Exception e){
            e.printStackTrace();
        }
        return null;
    }

 

    //私鑰解密
    public static String decrypt(String content, PrivateKey privateKey) {
        try {
//            Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");
            Security.addProvider(new org.bouncycastle.jce.provider.BouncyCastleProvider());
            Cipher cipher = Cipher.getInstance("RSA/NONE/OAEPWITHSHA256AndMGF1Padding","BC");
            cipher.init(Cipher.DECRYPT_MODE, privateKey);
            BASE64Decoder decoder = new BASE64Decoder();
            byte[] decodeBuffer = decoder.decodeBuffer(content);
            byte [] b = cipher.doFinal(decodeBuffer);
            return new String(b);
        } catch (Exception e){
            e.printStackTrace();
            return null;
        }
    }

 測試

private static String data2 ="g7ZcUMRAIAsVDwrAFi5F4uia6KhW3gCbyfKLDxLWiBTbHuJpfPA3iSLz7RYs9/6tMO6Vq8kG4nJs9+OMyK0psK/iCLA8PsEVRczsNNJ9OS10eZ/MbKoCpRRCC89aHf59JQy757g1wquq5yCXbnJRPd7lQYobJnxp1ZeBWB9NwruISt075/6sS8Kram2IXFLP5LypFNWRCPB9HVKz3HFlLqRH0lWfIbPO1VDYsK6ooRvRbr4MnRAACs+p92VeAg6NRcqWvP4o7f/wY3DcBYpXLVfxSQjuRG0t3t61Agc81COPaelk1f2SShtmsX8MyAZWdZpTqnTwIVRiRIXjl8PHXw==";

public static void main(String[] args) throws NoSuchAlgorithmException, InvalidKeySpecException, NoSuchPaddingException, IllegalBlockSizeException, BadPaddingException, InvalidKeyException, IOException {
        try
        {
            String  ss = "TKG-Jqs1g_O_4D37fFkOv9NGBqtPXTo-zc7b1VFf-OY";
            PublicKey publicKey4 = getPublicKey(yourPublicKey);
            String encrypt = encrypt(ss, publicKey4);
            System.out.println(encrypt);
            
            PrivateKey privateKey4 = getPrivateKey(your_PRIVATE_KEY);
            String decrypt = decrypt(data2, privateKey4);
            System.out.println(decrypt);
        }
        catch (Exception e)
        {
            e.printStackTrace();
        }
    }

 

    /**
     * String轉公鑰PublicKey
     * @param key
     * @return
     * @throws Exception
     */
    public static PublicKey getPublicKey(String key) throws Exception {
        byte[] keyBytes;
        keyBytes = (new BASE64Decoder()).decodeBuffer(key);
        X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance("RSA");
        PublicKey publicKey = keyFactory.generatePublic(keySpec);
        return publicKey;
    }

    /**
     * String轉私鑰PrivateKey
     * @param key
     * @return
     * @throws Exception
     */
    public static PrivateKey getPrivateKey(String key) throws Exception {
        byte[] keyBytes;
        keyBytes = (new BASE64Decoder()).decodeBuffer(key);
        PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance("RSA");
        PrivateKey privateKey = keyFactory.generatePrivate(keySpec);
        return privateKey;
    }