Java非对称加密算法RSA

﹏ヽ暗。殇╰゛Y 2022-07-16 10:43 255阅读 0赞

主方法类：

import javafx.scene.effect.DisplacementMap;
    
    import java.security.interfaces.RSAPrivateKey;
    import java.security.interfaces.RSAPublicKey;
    import java.util.HashMap;
    import java.util.Map;
    
    /**
     * Created by cuboo on 2016/10/14.
     */
    public class Main {
        public static void main(String agrs[]) throws Exception {
            Map<String,Object> map;
            map = RSAcode.GenerateKeyPair("RSA",1024);
            RSAPublicKey publicKey = RSAcode.GetPublicKey(map);
            RSAPrivateKey privateKey = RSAcode.GetPrivateKey(map);
            byte[] encryptdata = RSAcode.encrypt(publicKey,"RSA","hello abc".getBytes());
            byte[] decryptdata = RSAcode.decrypt(privateKey,"RSA",encryptdata);
            System.out.println("公钥："+publicKey);
            System.out.println("私钥："+privateKey);
            System.out.println("加密："+fromBytesToHexString(encryptdata));
            System.out.println("解密："+new String(decryptdata));
        }
    
        public static String fromBytesToHexString(byte[] data){
            StringBuilder str = new StringBuilder();
            for (int i = 0; i < data.length; i++) {
                 String s = Integer.toHexString(0xFF & data[i]);
                if (s.length() == 1){
                    str.append(0).append(s);
                }else {
                    str.append(s);
                }
            }
            return str.toString();
        }
    
        //十六进制字符串转字节数组
        public static byte[] fromHexStringToBytes(String hexString) {
    
            if ((hexString == null) || (hexString.equals("")) || hexString.length()%2 != 0){
                return null;
            }else{
                hexString = hexString.toUpperCase();
                int length = hexString.length()/2;
                char[] bytec = hexString.toCharArray();
                byte[] bit = new byte[length];
                for (int i = 0; i < length; i++){
                    int p = 2 * i;
                    //两个十六进制字符转换成1个字节，第1个字符转换成byte后左移4位，然后和第2个字符的byte做或运算
                    bit[i] = (byte) (fromCharToByte(bytec[p]) << 4 | fromCharToByte(bytec[p + 1]));
                }
                return bit;
            }
        }
    
        //字符转换为字节
        private static byte fromCharToByte(char c) {
            return (byte) "0123456789ABCDEF".indexOf(c);
        }
    
    }

方法类：

import javax.crypto.Cipher;
    import javax.crypto.SecretKey;
    import javax.crypto.spec.SecretKeySpec;
    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;
    
    /**
     * Created by cuboo on 2016/10/15.
     */
    public class RSAcode {
        private static final String PUBLIC_KEY = "publickey";
        private static final String PRIVATE_KEY = "privatekey";
    
        /*
            *步骤1生成公钥和私钥 keyType = "RSA" keySize = 1024 512 - 65536(64的整数倍)
            */
        public static Map<String,Object> GenerateKeyPair(String keyType, int keySize) throws Exception {
            KeyPairGenerator pairGenerator = KeyPairGenerator.getInstance(keyType);
            pairGenerator.initialize(keySize);
            //生成秘钥对
            KeyPair keyPair = pairGenerator.generateKeyPair();
            //获得公钥和私钥
            RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();
            RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();
            Map<String,Object> map = new HashMap<String,Object>();
            map.put(PUBLIC_KEY,publicKey);
            map.put(PRIVATE_KEY,privateKey);
            return  map;
        }
        /*
            *加密
            */
        public static byte[] encrypt(RSAPublicKey publickey,String keyType,byte[] data)
                throws Exception {
            Cipher cipher = Cipher.getInstance(keyType);
            cipher.init(Cipher.ENCRYPT_MODE,publickey);
            return cipher.doFinal(data);
        }
    
        /*
        *解密
        */
        public static byte[] decrypt(RSAPrivateKey privateKey,String keyType,byte[] data)
                throws Exception {
            Cipher cipher = Cipher.getInstance(keyType);
            cipher.init(Cipher.DECRYPT_MODE,privateKey);
            return cipher.doFinal(data);
        }
        /*
        *从Map中获得密钥对
        */
        public static RSAPublicKey GetPublicKey(Map<String,Object> map){
            RSAPublicKey publicKey = (RSAPublicKey) map.get(PUBLIC_KEY);
            return publicKey;
        }
        public static RSAPrivateKey GetPrivateKey(Map<String,Object> map){
            RSAPrivateKey privateKey = (RSAPrivateKey) map.get(PRIVATE_KEY);
            return privateKey;
        }
        
    }