JWT应用学习笔记（一） —— Rsakey私钥密钥生成工具

public class RsaKeyHelper {
    public RsaKeyHelper() {
    }
   
    //将公钥导入并返回按照 X.509 标准进行编码的密钥的字节
    public PublicKey getPublicKey(String filename) throws Exception {
        InputStream resourceAsStream = this.getClass().getClassLoader().getResourceAsStream(filename);
        DataInputStream dis = new DataInputStream(resourceAsStream);
        byte[] keyBytes = new byte[resourceAsStream.available()];
        dis.readFully(keyBytes);
        dis.close();
        X509EncodedKeySpec spec = new X509EncodedKeySpec(keyBytes);
        KeyFactory kf = KeyFactory.getInstance("RSA");
        return kf.generatePublic(spec);
    }

   //导入密钥并生成使用PKCS#8标准作为密钥规范管理的编码格式私钥
    public PrivateKey getPrivateKey(String filename) throws Exception {
        InputStream resourceAsStream = this.getClass().getClassLoader().getResourceAsStream(filename);
        DataInputStream dis = new DataInputStream(resourceAsStream);
        byte[] keyBytes = new byte[resourceAsStream.available()];
        dis.readFully(keyBytes);
        dis.close();
        PKCS8EncodedKeySpec spec = new PKCS8EncodedKeySpec(keyBytes);
        KeyFactory kf = KeyFactory.getInstance("RSA");
        return kf.generatePrivate(spec);
    }
    //传入公钥并返回按照 X.509 标准进行编码的公钥的字节
    public PublicKey getPublicKey(byte[] publicKey) throws Exception {
        X509EncodedKeySpec spec = new X509EncodedKeySpec(publicKey);
        KeyFactory kf = KeyFactory.getInstance("RSA");
        return kf.generatePublic(spec);
    }
    //传入密钥返回使用PKCS#8标准作为密钥规范管理的编码格式密钥
    public PrivateKey getPrivateKey(byte[] privateKey) throws Exception {
        PKCS8EncodedKeySpec spec = new PKCS8EncodedKeySpec(privateKey);
        KeyFactory kf = KeyFactory.getInstance("RSA");
        return kf.generatePrivate(spec);
    }
 
   //生成秘钥对，程序启动时可以运行以下方法，将生成的秘钥对放在静态变量里面存放，方便后续使用
    public static Map generateKey(String password) throws IOException, NoSuchAlgorithmException {
        KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA");
        SecureRandom secureRandom = new SecureRandom(password.getBytes());
       //根据随机种子生成秘钥对
        keyPairGenerator.initialize(1024, secureRandom);
        KeyPair keyPair = keyPairGenerator.genKeyPair();
        byte[] publicKeyBytes = keyPair.getPublic().getEncoded();
        byte[] privateKeyBytes = keyPair.getPrivate().getEncoded();
        Map map = new HashMap();
        map.put("pub", publicKeyBytes);
        map.put("pri", privateKeyBytes);
        return map;
    }

    public static String toHexString(byte[] b) {
        return (new BASE64Encoder()).encodeBuffer(b);
    }

    public static final byte[] toBytes(String s) throws IOException {
        return (new BASE64Decoder()).decodeBuffer(s);
    }
}

X.509是定义了公钥证书结构的基本标准： 

PKCS#8：私钥信息语法标准。PKCS#8定义了私钥信息语法和加密私钥语法，其中私钥加密使用了PKCS#5标准：