Java中数字签名RSASignature 算法的使用

小灰灰 2022-07-16 10:47 146阅读 0赞

import java.security.*;
    import java.security.interfaces.RSAPrivateKey;
    import java.security.interfaces.RSAPublicKey;
    import java.security.spec.PKCS8EncodedKeySpec;
    import java.util.HashMap;
    import java.util.Map;
    
    /**
     * Created by cuboo on 2016/10/15.
     */
    public class RSAsignature {
        private static final String PUBLIC_KEY = "publickey";
        private static final String PRIVATE_KEY = "privatekey";
    
        /*
         *RSA生成密钥对
         */
        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;
        }
        /*
        *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;
        }
        /*
         *私钥对原始数据进行签名
         */
        public static byte[] signature(RSAPrivateKey privateKey ,byte[] data,String keyType) throws Exception {
    //        PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(privateKey.getEncoded());
    //        KeyFactory factory = KeyFactory.getInstance(keyType);
    //        PrivateKey privatekey = (PrivateKey) factory.generatePrivate(keySpec);
    
            Signature signature = Signature.getInstance("MD5withRSA");
            signature.initSign(privateKey);
            signature.update(data);
            return signature.sign();
        }
        /*
         * 公钥、原始数据、原始签名数据进行验证
         */
        public static boolean verify(RSAPublicKey publicKey,byte[] data,byte[] sign) throws Exception {
            Signature signature = Signature.getInstance("MD5withRSA");
            signature.initVerify(publicKey);
            signature.update(data);
            return signature.verify(sign);
        }
    
        public static void main(String agrs[]) throws Exception {
            Map<String,Object> map = GenerateKeyPair("RSA",1024);
            RSAPublicKey publicKey = RSAcode.GetPublicKey(map);
            RSAPrivateKey privateKey = RSAcode.GetPrivateKey(map);
            byte[] sign = signature(privateKey,"abc".getBytes(),"RSA");
            boolean verify = verify(publicKey,"abc1".getBytes(),sign);
    
            System.out.println(fromBytesToHexString(publicKey.getEncoded()));
            System.out.println(fromBytesToHexString(privateKey.getEncoded()));
            System.out.println(fromBytesToHexString(sign));
            System.out.println(verify);
        }
        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();
        }
    }