java 实现区块链的密码学

- 日理万妓 2023-10-02 20:24 9阅读 0赞

java 实现区块链的密码学今天分享，首先区块链行业相关的密码学有几个思路，比如对称加解密、非对称加解密、数字签名算法、散列hash相关的SHA-256加解密、Merkle树相关算法等等。今天我们主要采用java语言分享非对称加密和数字签名。

1、相关jar等配置，配置JDK1.8版本加上下面的jar包

<dependency>
    		    <groupId>junit</groupId>
    		    <artifactId>junit</artifactId>
    		    <version>4.9</version>
    		    <scope>test</scope>
    		</dependency>

2、生成公钥和私钥的伪代码：

import static org.junit.Assert.*;
    
    import org.junit.Before;
    import org.junit.Test;
    
    import java.util.Map;
    
    
      //核心方法
      private String publicKey;
    	private String privateKey;
    
    	@Before
    	public void setUp() throws Exception {
    		Map<String, Object> keyMap = RSACoder.initKey();
    
    		publicKey = RSACoder.getPublicKey(keyMap);
    		privateKey = RSACoder.getPrivateKey(keyMap);
    		System.err.println("公钥: \n\r" + publicKey);
    		System.err.println("私钥： \n\r" + privateKey);
    	}

3、非对称加密

原理图

![d207818951fd4e4f882001d556a60e28.png][]

伪代码

@Test
    	public void testEncrypt() throws Exception {
    		System.err.println("公钥加密——私钥解密");
    		String inputStr = "abc";
    		byte[] data = inputStr.getBytes();
    
    		byte[] encodedData = RSACoder.encryptByPublicKey(data, publicKey);
    
    		byte[] decodedData = RSACoder.decryptByPrivateKey(encodedData, privateKey);
    
    		String outputStr = new String(decodedData);
    		System.err.println("加密前: " + inputStr + "\n\r" + "解密后: " + outputStr);
    		assertEquals(inputStr, outputStr);
    
    	}

4、数字签名

原理图

![867198d45e48412384d4b1e3c7e71583.png][]

伪代码

@Test
    	public void testSign() throws Exception {
    		System.err.println("私钥签名——公钥验证签名");
    		String inputStr = "sign";
    		byte[] data = inputStr.getBytes();
    
    		// 产生签名
    		String sign = RSACoder.sign(data, privateKey);
    		System.err.println("签名:\r" + sign);
    
    		
    		// 验证签名
    		boolean status = RSACoder.verify(data, publicKey, sign);
    		System.err.println("状态:\r" + status);
    		assertTrue(status);
    
    	}

5、通过的封装的工具类

import java.security.Key;
    import java.security.KeyFactory;
    import java.security.KeyPair;
    import java.security.KeyPairGenerator;
    import java.security.PrivateKey;
    import java.security.PublicKey;
    import java.security.Signature;
    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;
    
    import javax.crypto.Cipher;
    
    /**
     * RSA安全编码组件
     * 
     */
    public abstract class RSACoder extends Coder {
    	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";
    
    	/**
    	 * 用私钥对信息生成数字签名
    	 * 
    	 * @param data
    	 *            加密数据
    	 * @param privateKey
    	 *            私钥
    	 * 
    	 * @return
    	 * @throws Exception
    	 */
    	public static String sign(byte[] data, String privateKey) throws Exception {
    		// 解密由base64编码的私钥
    		byte[] keyBytes = decryptBASE64(privateKey);
    
    		// 构造PKCS8EncodedKeySpec对象
    		PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
    
    		// KEY_ALGORITHM 指定的加密算法
    		KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
    
    		// 取私钥匙对象
    		PrivateKey priKey = keyFactory.generatePrivate(pkcs8KeySpec);
    
    		// 用私钥对信息生成数字签名
    		Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);
    		signature.initSign(priKey);
    		signature.update(data);
    
    		return encryptBASE64(signature.sign());
    	}
    
    	/**
    	 * 校验数字签名
    	 * 
    	 * @param data
    	 *            加密数据
    	 * @param publicKey
    	 *            公钥
    	 * @param sign
    	 *            数字签名
    	 * 
    	 * @return 校验成功返回true 失败返回false
    	 * @throws Exception
    	 * 
    	 */
    	public static boolean verify(byte[] data, String publicKey, String sign) throws Exception {
    
    		// 解密由base64编码的公钥
    		byte[] keyBytes = decryptBASE64(publicKey);
    
    		// 构造X509EncodedKeySpec对象
    		X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);
    
    		// KEY_ALGORITHM 指定的加密算法
    		KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
    
    		// 取公钥匙对象
    		PublicKey pubKey = keyFactory.generatePublic(keySpec);
    
    		Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);
    		signature.initVerify(pubKey);
    		signature.update(data);
    
    		// 验证签名是否正常
    		return signature.verify(decryptBASE64(sign));
    	}
    
    	/**
    	 * 解密<br>
    	 * 用私钥解密
    	 * 
    	 * @param data
    	 * @param key
    	 * @return
    	 * @throws Exception
    	 */
    	public static byte[] decryptByPrivateKey(byte[] data, String key) throws Exception {
    		// 对密钥解密
    		byte[] keyBytes = decryptBASE64(key);
    
    		// 取得私钥
    		PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
    		KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
    		Key privateKey = keyFactory.generatePrivate(pkcs8KeySpec);
    
    		// 对数据解密
    		Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
    		cipher.init(Cipher.DECRYPT_MODE, privateKey);
    
    		return cipher.doFinal(data);
    	}
    
    	/**
    	 * 解密<br>
    	 * 用公钥解密
    	 * 
    	 * @param data
    	 * @param key
    	 * @return
    	 * @throws Exception
    	 */
    	public static byte[] decryptByPublicKey(byte[] data, String key) throws Exception {
    		// 对密钥解密
    		byte[] keyBytes = decryptBASE64(key);
    
    		// 取得公钥
    		X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);
    		KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
    		Key publicKey = keyFactory.generatePublic(x509KeySpec);
    
    		// 对数据解密
    		Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
    		cipher.init(Cipher.DECRYPT_MODE, publicKey);
    
    		return cipher.doFinal(data);
    	}
    
    	/**
    	 * 加密<br>
    	 * 用公钥加密
    	 * 
    	 * @param data
    	 * @param key
    	 * @return
    	 * @throws Exception
    	 */
    	public static byte[] encryptByPublicKey(byte[] data, String key) throws Exception {
    		// 对公钥解密
    		byte[] keyBytes = decryptBASE64(key);
    
    		// 取得公钥
    		X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);
    		KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
    		Key publicKey = keyFactory.generatePublic(x509KeySpec);
    
    		// 对数据加密
    		Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
    		cipher.init(Cipher.ENCRYPT_MODE, publicKey);
    
    		return cipher.doFinal(data);
    	}
    
    	/**
    	 * 加密<br>
    	 * 用私钥加密
    	 * 
    	 * @param data
    	 * @param key
    	 * @return
    	 * @throws Exception
    	 */
    	public static byte[] encryptByPrivateKey(byte[] data, String key) throws Exception {
    		// 对密钥解密
    		byte[] keyBytes = decryptBASE64(key);
    
    		// 取得私钥
    		PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
    		KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
    		Key privateKey = keyFactory.generatePrivate(pkcs8KeySpec);
    
    		// 对数据加密
    		Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
    		cipher.init(Cipher.ENCRYPT_MODE, privateKey);
    
    		return cipher.doFinal(data);
    	}
    
    	/**
    	 * 取得私钥
    	 * 
    	 * @param keyMap
    	 * @return
    	 * @throws Exception
    	 */
    	public static String getPrivateKey(Map<String, Object> keyMap) throws Exception {
    		Key key = (Key) keyMap.get(PRIVATE_KEY);
    
    		return encryptBASE64(key.getEncoded());
    	}
    
    	/**
    	 * 取得公钥
    	 * 
    	 * @param keyMap
    	 * @return
    	 * @throws Exception
    	 */
    	public static String getPublicKey(Map<String, Object> keyMap) throws Exception {
    		Key key = (Key) keyMap.get(PUBLIC_KEY);
    
    		return encryptBASE64(key.getEncoded());
    	}
    	
    	public static void main(String[] args) throws Exception {
    		String text = encryptBASE64("1".getBytes("UTF-8"));
    		System.out.println(new String(decryptBASE64(text)));
        }
    
    	/**
    	 * 初始化密钥
    	 * 
    	 * @return
    	 * @throws Exception
    	 */
    	public static Map<String, Object> initKey() throws Exception {
    		KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance(KEY_ALGORITHM);
    		keyPairGen.initialize(1024);
    
    		KeyPair keyPair = keyPairGen.generateKeyPair();
    
    		// 公钥
    		RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();
    
    		// 私钥
    		RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();
    
    		Map<String, Object> keyMap = new HashMap<String, Object>(2);
    
    		keyMap.put(PUBLIC_KEY, publicKey);
    		keyMap.put(PRIVATE_KEY, privateKey);
    		return keyMap;
    	}
    }

6、测试数字签名，打印结果

![792326cdf7774e7b91a0f9513dd20dba.png][]

7、对称加密原理

![96d934dee1f245a78d7207d86d0fa070.png][]

8、hash加密原理

![1bf39881221041d79b8e05f4c3845959.png][]

总结、一般情况下区块链是采用的数字签名加密算法，同时额外加一些参数，比如摘要等等。

到此、非对称加密和数字签名分享结束，下篇我们分享数字钱包的生成原理，敬请期待！

[d207818951fd4e4f882001d556a60e28.png]: https://img-blog.csdnimg.cn/d207818951fd4e4f882001d556a60e28.png
[867198d45e48412384d4b1e3c7e71583.png]: https://img-blog.csdnimg.cn/867198d45e48412384d4b1e3c7e71583.png
[792326cdf7774e7b91a0f9513dd20dba.png]: https://img-blog.csdnimg.cn/792326cdf7774e7b91a0f9513dd20dba.png
[96d934dee1f245a78d7207d86d0fa070.png]: https://img-blog.csdnimg.cn/96d934dee1f245a78d7207d86d0fa070.png
[1bf39881221041d79b8e05f4c3845959.png]: https://img-blog.csdnimg.cn/1bf39881221041d79b8e05f4c3845959.png