Java加密技术 数字证书

一、制作证书 

1.生成keyStroe文件 
在命令行下执行以下命令： 

keytool -genkey -validity 1 -alias www.tzz-sf.com -keyalg RSA -keystore d:\tzz-sf.keystore

 其中 

-genkey    表示生成密钥 
-validity     指定证书有效期，这里是1天 
-alias         指定别名，这里是www.tzz-sf.com

-keyalg      指定算法，这里是RSA 
-keystore   指定存储位置，这里是d:\tzz-sf.keystore

根据命令行提示输入：

输入keystore密码：
Keystore 密码太短 -至少必须为6个字符
输入keystore密码：
再次输入新密码:
您的名字与姓氏是什么？
  [Unknown]：  tzz
您的组织单位名称是什么？
  [Unknown]：  www.tzz-sf.com
您的组织名称是什么？
  [Unknown]：  tzz-sf
您所在的城市或区域名称是什么？
  [Unknown]：  sz
您所在的州或省份名称是什么？
  [Unknown]：  sz
该单位的两字母国家代码是什么
  [Unknown]：  cn
CN=tzz, OU=www.tzz-sf.com, O=tzz-sf, L=sz, ST=sz, C=cn 正确吗？
  [否]：  y
输入<www.tzz-sf.com>的主密码

 在这里我使用的密码为 123456789

2.生成自签名证书 
光有keyStore文件是不够的，还需要证书文件，证书才是直接提供给外界使用的公钥凭证。 

keytool -export -keystore d:\tzz-sf.keystore -alias www.tzz-sf.com -file d:\tzz-sf.cer -rfc

 其中 

-export      指定为导出操作 
-keystore  指定keystore文件 
-alias        指定导出keystore文件中的别名 
-file           指向导出路径 
-rfc            以文本格式输出，也就是以BASE64编码输出 
这里的密码是 123456789

当然，使用方是需要导入证书的！ 
可以通过自签名证书完成CAS单点登录系统的构建！

import java.io.IOException;

import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;

public class Coder {

	public static String encryptBASE64(byte[] key) {  
		return (new BASE64Encoder()).encodeBuffer(key);  
	}
	
	public static byte[] decryptBASE64(String key) throws IOException {  
		return new BASE64Decoder().decodeBuffer(key);
	}
}

 

package cn.tzz.java.crypto.certificate;

import java.io.FileInputStream;
import java.security.KeyStore;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.Signature;
import java.security.cert.Certificate;
import java.security.cert.CertificateFactory;
import java.security.cert.X509Certificate;
import java.util.Date;

import javax.crypto.Cipher;

import cn.tzz.java.crypto.Coder;

/**
 * Java加密技术——数字证书
 * 
 */
public abstract class CertificateCryptUtil extends Coder {

	/**
	 * Java密钥库(Java Key Store，JKS)KEY_STORE
	 */
	public static final String KEY_STORE = "JKS";

	public static final String X509 = "X.509";

	/**
	 * 由KeyStore获得私钥
	 * 
	 * @param keyStorePath
	 * @param alias
	 * @param password
	 * @return
	 * @throws Exception
	 */
	private static PrivateKey getPrivateKey(String keyStorePath, String alias, String password) throws Exception {
		KeyStore ks = getKeyStore(keyStorePath, password);
		PrivateKey key = (PrivateKey) ks.getKey(alias, password.toCharArray());
		return key;
	}

	/**
	 * 由Certificate获得公钥
	 * 
	 * @param certificatePath
	 * @return
	 * @throws Exception
	 */
	private static PublicKey getPublicKey(String certificatePath) throws Exception {
		Certificate certificate = getCertificate(certificatePath);
		PublicKey key = certificate.getPublicKey();
		return key;
	}

	/**
	 * 获得Certificate
	 * 
	 * @param certificatePath
	 * @return
	 * @throws Exception
	 */
	private static Certificate getCertificate(String certificatePath) throws Exception {
		CertificateFactory certificateFactory = CertificateFactory.getInstance(X509);
		FileInputStream in = new FileInputStream(certificatePath);

		Certificate certificate = certificateFactory.generateCertificate(in);
		in.close();
		return certificate;
	}

	/**
	 * 获得Certificate
	 * 
	 * @param keyStorePath
	 * @param alias
	 * @param password
	 * @return
	 * @throws Exception
	 */
	private static Certificate getCertificate(String keyStorePath, String alias, String password) throws Exception {
		KeyStore ks = getKeyStore(keyStorePath, password);
		Certificate certificate = ks.getCertificate(alias);
		return certificate;
	}

	/**
	 * 获得KeyStore
	 * 
	 * @param keyStorePath
	 * @param password
	 * @return
	 * @throws Exception
	 */
	private static KeyStore getKeyStore(String keyStorePath, String password) throws Exception {
		FileInputStream is = new FileInputStream(keyStorePath);
		KeyStore ks = KeyStore.getInstance(KEY_STORE);
		ks.load(is, password.toCharArray());
		is.close();
		return ks;
	}

	/**
	 * 私钥加密
	 * 
	 * @param data
	 * @param keyStorePath
	 * @param alias
	 * @param password
	 * @return
	 * @throws Exception
	 */
	public static byte[] encryptByPrivateKey(byte[] data, String keyStorePath, String alias, String password) throws Exception {
		// 取得私钥
		PrivateKey privateKey = getPrivateKey(keyStorePath, alias, password);
		// 对数据加密
		Cipher cipher = Cipher.getInstance(privateKey.getAlgorithm());
		cipher.init(Cipher.ENCRYPT_MODE, privateKey);
		return cipher.doFinal(data);
	}

	/**
	 * 私钥解密
	 * 
	 * @param data
	 * @param keyStorePath
	 * @param alias
	 * @param password
	 * @return
	 * @throws Exception
	 */
	public static byte[] decryptByPrivateKey(byte[] data, String keyStorePath, String alias, String password) throws Exception {
		// 取得私钥
		PrivateKey privateKey = getPrivateKey(keyStorePath, alias, password);
		// 对数据加密
		Cipher cipher = Cipher.getInstance(privateKey.getAlgorithm());
		cipher.init(Cipher.DECRYPT_MODE, privateKey);
		return cipher.doFinal(data);
	}

	/**
	 * 公钥加密
	 * 
	 * @param data
	 * @param certificatePath
	 * @return
	 * @throws Exception
	 */
	public static byte[] encryptByPublicKey(byte[] data, String certificatePath) throws Exception {
		// 取得公钥
		PublicKey publicKey = getPublicKey(certificatePath);
		// 对数据加密
		Cipher cipher = Cipher.getInstance(publicKey.getAlgorithm());
		cipher.init(Cipher.ENCRYPT_MODE, publicKey);
		return cipher.doFinal(data);
	}

	/**
	 * 公钥解密
	 * 
	 * @param data
	 * @param certificatePath
	 * @return
	 * @throws Exception
	 */
	public static byte[] decryptByPublicKey(byte[] data, String certificatePath) throws Exception {
		// 取得公钥
		PublicKey publicKey = getPublicKey(certificatePath);
		// 对数据加密
		Cipher cipher = Cipher.getInstance(publicKey.getAlgorithm());
		cipher.init(Cipher.DECRYPT_MODE, publicKey);
		return cipher.doFinal(data);
	}

	/**
	 * 验证Certificate
	 * 
	 * @param certificatePath
	 * @return
	 */
	public static boolean verifyCertificate(String certificatePath) {
		return verifyCertificate(new Date(), certificatePath);
	}

	/**
	 * 验证Certificate是否过期或无效
	 * 
	 * @param date
	 * @param certificatePath
	 * @return
	 */
	public static boolean verifyCertificate(Date date, String certificatePath) {
		boolean status = true;
		try {
			// 取得证书
			Certificate certificate = getCertificate(certificatePath);
			// 验证证书是否过期或无效
			status = verifyCertificate(date, certificate);
		} catch (Exception e) {
			status = false;
		}
		return status;
	}

	/**
	 * 验证证书是否过期或无效
	 * 
	 * @param date
	 * @param certificate
	 * @return
	 */
	private static boolean verifyCertificate(Date date, Certificate certificate) {
		boolean status = true;
		try {
			X509Certificate x509Certificate = (X509Certificate) certificate;
			x509Certificate.checkValidity(date);
		} catch (Exception e) {
			status = false;
		}
		return status;
	}

	/**
	 * 签名
	 * 
	 * @param keyStorePath
	 * @param alias
	 * @param password
	 * 
	 * @return
	 * @throws Exception
	 */
	public static String sign(byte[] sign, String keyStorePath, String alias, String password) throws Exception {
		// 获得证书
		X509Certificate x509Certificate = (X509Certificate) getCertificate(keyStorePath, alias, password);
		// 获取私钥
		KeyStore ks = getKeyStore(keyStorePath, password);
		// 取得私钥
		PrivateKey privateKey = (PrivateKey) ks.getKey(alias,password.toCharArray());
		// 构建签名
		Signature signature = Signature.getInstance(x509Certificate.getSigAlgName());
		signature.initSign(privateKey);
		signature.update(sign);
		return encryptBASE64(signature.sign());
	}

	/**
	 * 验证签名
	 * 
	 * @param data
	 * @param sign
	 * @param certificatePath
	 * @return
	 * @throws Exception
	 */
	public static boolean verify(byte[] data, String sign, String certificatePath) throws Exception {
		// 获得证书
		X509Certificate x509Certificate = (X509Certificate) getCertificate(certificatePath);
		// 获得公钥
		PublicKey publicKey = x509Certificate.getPublicKey();
		// 构建签名
		Signature signature = Signature.getInstance(x509Certificate.getSigAlgName());
		signature.initVerify(publicKey);
		signature.update(data);

		return signature.verify(decryptBASE64(sign));

	}

	/**
	 * 验证Certificate
	 * 
	 * @param keyStorePath
	 * @param alias
	 * @param password
	 * @return
	 */
	public static boolean verifyCertificate(Date date, String keyStorePath, String alias, String password) {
		boolean status = true;
		try {
			Certificate certificate = getCertificate(keyStorePath, alias, password);
			status = verifyCertificate(date, certificate);
		} catch (Exception e) {
			status = false;
		}
		return status;
	}

	/**
	 * 验证Certificate
	 * 
	 * @param keyStorePath
	 * @param alias
	 * @param password
	 * @return
	 */
	public static boolean verifyCertificate(String keyStorePath, String alias, String password) {
		return verifyCertificate(new Date(), keyStorePath, alias, password);
	}
}

 测试：

package cn.tzz.java.crypto.certificate;

import static org.junit.Assert.*;

import org.junit.Test;

/**
 * 测试--Java加密技术——数字证书
 * 
 */
public class CertificateCryptUtilTest {
	private String password = "123456789";
	private String alias = "www.tzz-sf.com";
	//生成证书
	//keytool -genkey -validity 1 -alias www.tzz-sf.com -keyalg RSA -keystore d:\tzz-sf.keystore
	//keytool -export -keystore d:\tzz-sf.keystore -alias www.tzz-sf.com -file d:\tzz-sf.cer -rfc
	private String keyStorePath = "d:/tzz-sf.keystore";
	private String certificatePath = "d:/tzz-sf.cer";

	/**公钥加密——私钥解密*/
	@Test
	public void test() throws Exception {
		String inputStr = "加密字符123456Abc";
		byte[] data = inputStr.getBytes();
		byte[] encrypt = CertificateCryptUtil.encryptByPublicKey(data, certificatePath);

		byte[] decrypt = CertificateCryptUtil.decryptByPrivateKey(encrypt, keyStorePath, alias, password);
		String outputStr = new String(decrypt);
		System.err.println("加密前: " + inputStr + "-----" + "解密后: " + outputStr);
		// 验证数据一致
		assertArrayEquals(data, decrypt);
		// 验证证书有效
		assertTrue(CertificateCryptUtil.verifyCertificate(certificatePath));
	}

	/**私钥加密——公钥解密*/
	@Test
	public void testSign() throws Exception {
		String inputStr = "加密字符123456Abc";
		byte[] data = inputStr.getBytes();
		byte[] encodedData = CertificateCryptUtil.encryptByPrivateKey(data, keyStorePath, alias, password);

		byte[] decodedData = CertificateCryptUtil.decryptByPublicKey(encodedData, certificatePath);

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

		// 产生签名
		String sign = CertificateCryptUtil.sign(encodedData, keyStorePath, alias, password);
		System.err.println("签名:\r" + sign);
		// 验证签名
		boolean status = CertificateCryptUtil.verify(encodedData, sign, certificatePath);
		System.err.println("状态:\r" + status);
		assertTrue(status);

	}
}