数字签名算法

ゝ一世哀愁。 2022-04-14 04:41 266阅读 0赞

**数字签名算法主要包含RSA、DSA、ECDSA三种算法**

**1. 它的消息传递操作是：**

*  由消息发送方构建密匙对，
 *  由消息发送的一方公布公钥至消息接收方，
 *  消息发送方对消息用私钥做签名处理
 *  消息接收方用公钥对消息做验证

**2. RSA签名算法主要分为MD系列和SHA系列。具体实现如下：**  
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**3. RSA的数字签名代码实现：**  
DSA签名实现类似，ECDSA实现相比前两者在密匙对成功的方式上存在差别。

import org.apache.commons.codec.binary.Base64;
    
    import java.security.*;
    import java.security.interfaces.RSAPrivateKey;
    import java.security.interfaces.RSAPublicKey;
    import java.security.spec.PKCS8EncodedKeySpec;
    import java.security.spec.X509EncodedKeySpec;
    import java.util.HashMap;
    import java.util.Map;
    
    public class RSASignature { 
    
        private static final String KEY_ALGORITHM="RSA";
        private static final String SIGNATURE_ALGORITHM="MD5withRSA";
        private static final String PUBLIC_KEY="RSAPublicKey";
        private static final String PRIVATE_KEY="RSAPrivateKey";
        /** * RSA密匙长度，默认是1024位，密匙长度必须是在64的倍数 * 范围是512--65536之间 * */
        private static final int KEY_SIZE = 512;
    
        public static void main(String[] args) throws Exception { 
    
            String str = "hello vison";
            Map<String, Object> map = initKey();
            byte[] privateKey = getPrivateKey(map);
            //签名
            byte[] signData = sign(str.getBytes(), privateKey);
            System.out.println("signData: " + Base64.encodeBase64(signData));
            //校验
            byte[] pulicKey = getPulicKey(map);
            boolean status = verify(str.getBytes(), pulicKey, signData);
            System.out.println("verify result: " + status);
    
        }
    
        /** * * @param data 待校验的数据 * @param key 公钥 * @param sign 数据签名 * @return boolean 校验成功返回true,否则返回false * @throws Exception */
        public static boolean verify(byte[] data,byte[] key,byte[] sign)throws Exception{ 
            //获取公钥
            X509EncodedKeySpec x509EncodedKeySpec = new X509EncodedKeySpec(key);
            KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
            PublicKey publicKey = keyFactory.generatePublic(x509EncodedKeySpec);
            //校验数据
            Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);
            signature.initVerify(publicKey);
            signature.update(data);
            return signature.verify(sign);
        }
        /** * 私钥签名 * @param data 待签名数据 * @param key 私钥 * @return byte[] 加密数据 * @throws Exception */
        public static byte[] sign(byte[] data,byte[] key) throws Exception { 
            //获取私钥
            PKCS8EncodedKeySpec pkcs8EncodedKeySpec = new PKCS8EncodedKeySpec(key);
            KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
            PrivateKey privateKey = keyFactory.generatePrivate(pkcs8EncodedKeySpec);
            //签名
            Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);
            signature.initSign(privateKey);
            signature.update(data);
            return signature.sign();
        }
        /** * 获取私钥 * @param keyMap * @return */
        public static byte[] getPrivateKey(Map<String,Object> keyMap){ 
            Key key = (Key) keyMap.get(PRIVATE_KEY);
            return key.getEncoded();
        }
        /** * 获取公钥 * @param keyMap * @return */
        public static byte[] getPulicKey(Map<String,Object> keyMap){ 
            Key key = (Key) keyMap.get(PUBLIC_KEY);
            return key.getEncoded();
    
        }
        /** * 初始化密匙对 * @return Map 密钥map * @throws Exception */
        public static Map<String,Object> initKey() throws Exception { 
            //实例化密钥对生成器
            KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance(KEY_ALGORITHM);
            //初始化
            keyPairGenerator.initialize(KEY_SIZE);
            //生成密匙对
            KeyPair keyPair = keyPairGenerator.genKeyPair();
            //私钥
            RSAPrivateKey privateKey = (RSAPrivateKey)keyPair.getPrivate();
            //公钥
            RSAPublicKey publicKey = (RSAPublicKey)keyPair.getPublic();
            //封装密钥
            HashMap<String, Object> map = new HashMap<>(2);
            map.put(PUBLIC_KEY,publicKey);
            map.put(PRIVATE_KEY,privateKey);
            return map;
        }
    }

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