欢迎您访问程序员文章站本站旨在为大家提供分享程序员计算机编程知识!
您现在的位置是: 首页

RSA加密例子和中途遇到的问题 算法 RSA 

程序员文章站 2024-03-15 12:10:53
...
在进行RSA加密例子

package test;
import java.io.IOException;
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 sun.misc.BASE64Decoder; 
import sun.misc.BASE64Encoder;

import java.util.HashMap;
import java.util.Map;

import javax.crypto.Cipher;

public abstract class RSACoder {
	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";

	
	public static byte[] decryptBASE64(String privateKey){
		byte[] output = null;
		try {
			output = (new BASE64Decoder()).decodeBuffer(privateKey);
			return  output;
		} catch (IOException e) {
			e.printStackTrace();
		}
		return output;  
	}
	
	
	public static String encryptBASE64( byte[] keyBytes){
         String s = (new BASE64Encoder()).encode(keyBytes);
         return s;
	}
	
	/**
	 * 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());
	}

	/**
	 * 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;
	}
}




测试类


package test;
import java.util.Map;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import sun.misc.BASE64Decoder; 
import sun.misc.BASE64Encoder;
public class RSACoderTest {
	
package com;
import java.util.Map;
import sun.misc.BASE64Encoder;
public class RSACoderTest {
		static String privateKey ;
		static String publicKey ;
		public static void getKey() throws Exception {
		Map<String, Object> keyMap = RSACoder.initKey();

		publicKey = RSACoder.getPublicKey(keyMap);
		privateKey = RSACoder.getPrivateKey(keyMap);
		//公钥生成
		System.out.println("public : "+publicKey);
		//私钥生成
		System.out.println("private : "+privateKey);
	}
	public static void main(String[] args) throws Exception {
		 getKey() ;
//		System.err.println("公钥加密——私钥解密");
                //将明文转换为字节数组
		byte[] data = "serricee1".getBytes();
               //用公钥加密
		byte[] encodedData = RSACoder.encryptByPublicKey(data, publicKey);
                //打印加密字符串 为什么使用BASE64Encoder 因为在RSACoder里加密用的是 BASE64Encoder 加密
		String s = (new BASE64Encoder()).encode(encodedData);  
		System.err.println("加密: " +s);
//                //用私钥解密
		byte[] decodedData = RSACoder.decryptByPrivateKey(RSACoder.decryptBASE64(s),privateKey);
//
//		
		System.out.println( "解密后: " + new String(decodedData));
	}
	

}







遇到的问题在
解密的时候 用new BASE64Encoder()).encode(keyBytes); 获得明文发现明文长度只能是4的倍数而且不支持特殊字符串和中文不然解密出来不是多出来 就是解密不对 后面解密
直接用.getBytes() 和new String(decodedData)不用Base64的就好了

相关标签: 算法 RSA