How Springboot integrates JwtHelper to implement asymmetric encryption

1. Generate public and private key pairs

Provides two methods, one is based on the Keytool tool in the command line, and the other is based on the KeyPairGenerator class in SpringSecurity. The second method is now implemented:

//    加密算法
    private static final String KEY_ALGORITHM = "RSA";
//    公钥key
    private static final String PUB_KEY="publicKey";
//    私钥key
    private static final String PRI_KEY="privateKey";
 
    public static Map<String,String> generateKey() throws NoSuchAlgorithmException {
        Map<String,String> keyMap=new HashMap<>();
        KeyPairGenerator instance = KeyPairGenerator.getInstance(KEY_ALGORITHM);
        KeyPair keyPair = instance.generateKeyPair();
        PrivateKey privateKey = keyPair.getPrivate();
        PublicKey publicKey = keyPair.getPublic();
        //Base64 编码
        byte[] privateKeyEncoded = privateKey.getEncoded();
        String privateKeyStr = Base64.encodeBase64String(privateKeyEncoded);
        byte[] publicKeyEncoded = publicKey.getEncoded();
        String publicKeyStr=Base64.encodeBase64String(publicKeyEncoded);
        keyMap.put(PUB_KEY,publicKeyStr);
        keyMap.put(PRI_KEY,privateKeyStr);
        return keyMap;
    }

2. Use the private key to generate token

 //    加密算法
    private static final String KEY_ALGORITHM = "RSA";
    //    公钥key
    private static final String PUB_KEY="publicKey";
    //    私钥key
    private static final String PRI_KEY="privateKey";
//    GenerateKey Key=new GenerateKey();
//    利用私钥生产token
    public static Map<String,String> generateToken(UserDetails userDetails) throws NoSuchAlgorithmException, InvalidKeySpecException {
        GenerateKey Key=new GenerateKey();
        RSAPrivateKey privateKey = null;
        RSAPublicKey publicKey=null;
        String token=null;
        Map<String, String> map=new HashMap<>();
        Map<String, String> keyMap = Key.generateKey();
        privateKey=getPrivateKey(keyMap.get(PRI_KEY));
        Map<String,String> tokenMap=new HashMap<>();
        tokenMap.put("userName",userDetails.getUsername());
//        使用私钥加密
        token = JwtHelper.encode(JSON.toJSONString(tokenMap), new RsaSigner(privateKey)).getEncoded();
 
 
        map.put("token",token);
        map.put("publicKey",keyMap.get(PUB_KEY));
        return map;
    }

3. Use the public key to decrypt the token

public static String parseToken(String token,String publicKey) throws NoSuchAlgorithmException, InvalidKeySpecException {
        Jwt jwt=null;
        RSAPublicKey rsaPublicKey;
        rsaPublicKey=getPublicKey(publicKey);
        jwt=JwtHelper.decodeAndVerify(token, new RsaVerifier(rsaPublicKey) );
        String claims= jwt.getClaims();
        return claims;
    }

4. Convert the String type public key into an RSAPublicKey object

    /**
     * 得到公钥
     *
     * @param publicKey
     *            密钥字符串（经过base64编码）
     * @throws Exception
     */
    public static RSAPublicKey getPublicKey(String publicKey) throws NoSuchAlgorithmException, InvalidKeySpecException {
        // 通过X509编码的Key指令获得公钥对象
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(Base64.decodeBase64(publicKey));
        RSAPublicKey key = (RSAPublicKey) keyFactory.generatePublic(x509KeySpec);
        return key;
    }

5. Convert the private key of String type into RSAPrivateKey object

    /**
     * 得到私钥pkcs8
     *
     * @param privateKey
     *            密钥字符串（经过base64编码）
     * @throws Exception
     */
    public static RSAPrivateKey getPrivateKey(String privateKey)
            throws NoSuchAlgorithmException, InvalidKeySpecException {
        // 通过PKCS#8编码的Key指令获得私钥对象
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(Base64.decodeBase64(privateKey));
        RSAPrivateKey key = (RSAPrivateKey) keyFactory.generatePrivate(pkcs8KeySpec);
        return key;
    }

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