/**
 * 引進的包都是Java自帶的jar包
 * 秘鑰相關包
 * base64 編解碼
 * 這里只用到了編碼
 */
import java.security.Key;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.util.HashMap;
import java.util.Map;
import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;

public class CreateSecrteKey {

    
    public class Keys {
        
    }
    public static final String KEY_ALGORITHM = "RSA";
    //public static final String SIGNATURE_ALGORITHM = "MD5withRSA";
    private static final String PUBLIC_KEY = "RSAPublicKey";
    private static final String PRIVATE_KEY = "RSAPrivateKey";

    //獲得公鑰
    public static String getPublicKey(Map<String, Object> keyMap) throws Exception {
        //獲得map中的公鑰對象 轉為key對象
        Key key = (Key) keyMap.get(PUBLIC_KEY);
        //byte[] publicKey = key.getEncoded();
        //編碼返回字符串
        return encryptBASE64(key.getEncoded());
    }

    //獲得私鑰
    public static String getPrivateKey(Map<String, Object> keyMap) throws Exception {
        //獲得map中的私鑰對象 轉為key對象
        Key key = (Key) keyMap.get(PRIVATE_KEY);
        //byte[] privateKey = key.getEncoded();
        //編碼返回字符串
        return encryptBASE64(key.getEncoded());
    }

    //解碼返回byte
    public static byte[] decryptBASE64(String key) throws Exception {
        return (new BASE64Decoder()).decodeBuffer(key);
    }

    //編碼返回字符串
    public static String encryptBASE64(byte[] key) throws Exception {
        return (new BASE64Encoder()).encodeBuffer(key);
    }
    
    //map對象中存放公私鑰
    public static Map<String, Object> initKey() throws Exception {
        //獲得對象 KeyPairGenerator 參數(shù) RSA 1024個字節(jié)
        KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance(KEY_ALGORITHM);
        keyPairGen.initialize(1024);
        //通過對象 KeyPairGenerator 獲取對象KeyPair
        KeyPair keyPair = keyPairGen.generateKeyPair();
        
        //通過對象 KeyPair 獲取RSA公私鑰對象RSAPublicKey RSAPrivateKey
        RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();
        RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();
        //公私鑰對象存入map中
        Map<String, Object> keyMap = new HashMap<String, Object>(2);
        keyMap.put(PUBLIC_KEY, publicKey);
        keyMap.put(PRIVATE_KEY, privateKey);
        return keyMap;
    }

    public static void main(String[] args) {
        Map<String, Object> keyMap;
        try {
            keyMap = initKey();
            String publicKey = getPublicKey(keyMap);
            System.out.println(publicKey);
            String privateKey = getPrivateKey(keyMap);
            System.out.println(privateKey);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }