Java的安全学习(包括加密，数字签名，证书和认证) JCA JCE

自己作个笔记:

package demo.jca.rsa;

import static org.junit.Assert.*;

import org.junit.Before;
import org.junit.Test;

import demo.jca.keystore.Coder;

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 这种算法1978年就出现了，它是第一个既能用于数据加密也能用于数字签名的算法。<br>
 * RSA同时有两把钥匙，公钥与私钥。同时支持数字签名。<br>
 * 数字签名的意义在于，对传输过来的数据进行校验。确保数据在传输过程中不被修改。
 * <ul>
 * 流程分析：
 * <li>甲方构建密钥对儿，将公钥公布给乙方，将私钥保留。</li>
 * <li>甲方使用私钥加密数据，然后用私钥对加密后的数据签名，发送给乙方签名以及加密后的数据；乙方使用公钥、签名来验证待解密数据是否有效，如果有效使用公钥对数据解密。</li>
 * <li>乙方使用公钥加密数据，向甲方发送经过加密后的数据；甲方获得加密数据，通过私钥解密。</li>
 * <ul>
 * 
 * @author Xin Zhang
 * @version 1.0
 * @since 1.0
 */
public class RSACoderTest {
	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);
	}

	@Test
	public void test() 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);

	}

	@Test
	public void testSign() throws Exception {
		System.err.println("私钥加密——公钥解密");
		String inputStr = "sign";
		byte[] data = inputStr.getBytes();
		byte[] encodedData = RSACoder.encryptByPrivateKey(data, privateKey);
		byte[] decodedData = RSACoder.decryptByPublicKey(encodedData, publicKey);

		String outputStr = new String(decodedData);
		System.err.println("加密前: " + inputStr + "\n\r" + "解密后: " + outputStr);
		assertEquals(inputStr, outputStr);

		System.err.println("私钥签名——公钥验证签名");
		// 产生签名
		String sign = RSACoder.sign(encodedData, privateKey);
		System.err.println("签名:\r" + sign);

		// 验证签名
		boolean status = RSACoder.verify(encodedData, publicKey, sign);
		System.err.println("状态:\r" + status);
		assertTrue(status);

	}

}

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 http://www.5a520.cn http://www.feng123.com
	 * 
	 * @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>
	 * 用私钥解密
	 * 
	 * @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;
	}
}

 

 

附件中拥有证书的