Java加密技术（五）——非对称加密算法的由来DH

 接下来我们分析DH加密算法，一种适基于密钥一致协议的加密算法。
DH
Diffie-Hellman算法(D-H算法)，密钥一致协议。是由公开密钥密码体制的奠基人Diffie和Hellman所提出的一种思想。简单的说就是允许两名用户在公开媒体上交换信息以生成"一致"的、可以共享的密钥。换句话说，就是由甲方产出一对密钥（公钥、私钥），乙方依照甲方公钥产生乙方密钥对（公钥、私钥）。以此为基线，作为数据传输保密基础，同时双方使用同一种对称加密算法构建本地密钥（SecretKey）对数据加密。这样，在互通了本地密钥（SecretKey）算法后，甲乙双方公开自己的公钥，使用对方的公钥和刚才产生的私钥加密数据，同时可以使用对方的公钥和自己的私钥对数据解密。不单单是甲乙双方两方，可以扩展为多方共享数据通讯，这样就完成了网络交互数据的安全通讯！该算法源于中国的同余定理——中国馀数定理。  

流程分析：

1.甲方构建密钥对儿，将公钥公布给乙方，将私钥保留；双方约定数据加密算法；乙方通过甲方公钥构建密钥对儿，将公钥公布给甲方，将私钥保留。
2.甲方使用私钥、乙方公钥、约定数据加密算法构建本地密钥，然后通过本地密钥加密数据，发送给乙方加密后的数据；乙方使用私钥、甲方公钥、约定数据加密算法构建本地密钥，然后通过本地密钥对数据解密。
3.乙方使用私钥、甲方公钥、约定数据加密算法构建本地密钥，然后通过本地密钥加密数据，发送给甲方加密后的数据；甲方使用私钥、乙方公钥、约定数据加密算法构建本地密钥，然后通过本地密钥对数据解密。

2. 
3. 

通过java代码实现如下： Coder类见 Java加密技术（一）

Java代码  

1. import java.security.Key;  
2. import java.security.KeyFactory;  
3. import java.security.KeyPair;  
4. import java.security.KeyPairGenerator;  
5. import java.security.PublicKey;  
6. import java.security.spec.PKCS8EncodedKeySpec;  
7. import java.security.spec.X509EncodedKeySpec;  
8. import java.util.HashMap;  
9. import java.util.Map;  
10.   
11. import javax.crypto.Cipher;  
12. import javax.crypto.KeyAgreement;  
13. import javax.crypto.SecretKey;  
14. import javax.crypto.interfaces.DHPrivateKey;  
15. import javax.crypto.interfaces.DHPublicKey;  
16. import javax.crypto.spec.DHParameterSpec;  
17.   
18. /** 
19.  * DH安全编码组件 
20.  *  
21.  * @author 梁栋 
22.  * @version 1.0 
23.  * @since 1.0 
24.  */  
25. public abstract class DHCoder extends Coder {  
26.     public static final String ALGORITHM = "DH";  
27.   
28.     /** 
29.      * 默认密钥字节数 
30.      *  
31.      * <pre> 
32.      * DH 
33.      * Default Keysize 1024   
34.      * Keysize must be a multiple of 64, ranging from 512 to 1024 (inclusive). 
35.      * </pre> 
36.      */  
37.     private static final int KEY_SIZE = 1024;  
38.   
39.     /** 
40.      * DH加密下需要一种对称加密算法对数据加密，这里我们使用DES，也可以使用其他对称加密算法。 
41.      */  
42.     public static final String SECRET_ALGORITHM = "DES";  
43.     private static final String PUBLIC_KEY = "DHPublicKey";  
44.     private static final String PRIVATE_KEY = "DHPrivateKey";  
45.   
46.     /** 
47.      * 初始化甲方密钥 
48.      *  
49.      * @return  
50.      * @throws Exception 
51.      */  
52.     public static Map<String, Object> initKey() throws Exception {  
53.         KeyPairGenerator keyPairGenerator = KeyPairGenerator  
54.                 .getInstance(ALGORITHM);  
55.         keyPairGenerator.initialize(KEY_SIZE);  
56.   
57.         KeyPair keyPair = keyPairGenerator.generateKeyPair();  
58.   
59.         // 甲方公钥  
60.         DHPublicKey publicKey = (DHPublicKey) keyPair.getPublic();  
61.   
62.         // 甲方私钥  
63.         DHPrivateKey privateKey = (DHPrivateKey) keyPair.getPrivate();  
64.   
65.         Map<String, Object> keyMap = new HashMap<String, Object>(2);  
66.   
67.         keyMap.put(PUBLIC_KEY, publicKey);  
68.         keyMap.put(PRIVATE_KEY, privateKey);  
69.         return keyMap;  
70.     }  
71.   
72.     /** 
73.      * 初始化乙方密钥 
74.      *  
75.      * @param key 
76.      *            甲方公钥 
77.      * @return 
78.      * @throws Exception 
79.      */  
80.     public static Map<String, Object> initKey(String key) throws Exception {  
81.         // 解析甲方公钥  
82.         byte[] keyBytes = decryptBASE64(key);  
83.         X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);  
84.         KeyFactory keyFactory = KeyFactory.getInstance(ALGORITHM);  
85.         PublicKey pubKey = keyFactory.generatePublic(x509KeySpec);  
86.   
87.         // 由甲方公钥构建乙方密钥  
88.         DHParameterSpec dhParamSpec = ((DHPublicKey) pubKey).getParams();  
89.   
90.         KeyPairGenerator keyPairGenerator = KeyPairGenerator  
91.                 .getInstance(keyFactory.getAlgorithm());  
92.         keyPairGenerator.initialize(dhParamSpec);  
93.   
94.         KeyPair keyPair = keyPairGenerator.generateKeyPair();  
95.   
96.         // 乙方公钥  
97.         DHPublicKey publicKey = (DHPublicKey) keyPair.getPublic();  
98.   
99.         // 乙方私钥  
100.         DHPrivateKey privateKey = (DHPrivateKey) keyPair.getPrivate();  
101.   
102.         Map<String, Object> keyMap = new HashMap<String, Object>(2);  
103.   
104.         keyMap.put(PUBLIC_KEY, publicKey);  
105.         keyMap.put(PRIVATE_KEY, privateKey);  
106.   
107.         return keyMap;  
108.     }  
109.   
110.     /** 
111.      * 加密<br> 
112.      *  
113.      * @param data 
114.      *            待加密数据 
115.      * @param publicKey 
116.      *            甲方公钥 
117.      * @param privateKey 
118.      *            乙方私钥 
119.      * @return 
120.      * @throws Exception 
121.      */  
122.     public static byte[] encrypt(byte[] data, String publicKey,  
123.             String privateKey) throws Exception {  
124.   
125.         // 生成本地密钥  
126.         SecretKey secretKey = getSecretKey(publicKey, privateKey);  
127.   
128.         // 数据加密  
129.         Cipher cipher = Cipher.getInstance(secretKey.getAlgorithm());  
130.         cipher.init(Cipher.ENCRYPT_MODE, secretKey);  
131.   
132.         return cipher.doFinal(data);  
133.     }  
134.   
135.     /** 
136.      * 解密<br> 
137.      *  
138.      * @param data 
139.      *            待解密数据 
140.      * @param publicKey 
141.      *            乙方公钥 
142.      * @param privateKey 
143.      *            乙方私钥 
144.      * @return 
145.      * @throws Exception 
146.      */  
147.     public static byte[] decrypt(byte[] data, String publicKey,  
148.             String privateKey) throws Exception {  
149.   
150.         // 生成本地密钥  
151.         SecretKey secretKey = getSecretKey(publicKey, privateKey);  
152.         // 数据解密  
153.         Cipher cipher = Cipher.getInstance(secretKey.getAlgorithm());  
154.         cipher.init(Cipher.DECRYPT_MODE, secretKey);  
155.   
156.         return cipher.doFinal(data);  
157.     }  
158.   
159.     /** 
160.      * 构建密钥 
161.      *  
162.      * @param publicKey 
163.      *            公钥 
164.      * @param privateKey 
165.      *            私钥 
166.      * @return 
167.      * @throws Exception 
168.      */  
169.     private static SecretKey getSecretKey(String publicKey, String privateKey)  
170.             throws Exception {  
171.         // 初始化公钥  
172.         byte[] pubKeyBytes = decryptBASE64(publicKey);  
173.   
174.         KeyFactory keyFactory = KeyFactory.getInstance(ALGORITHM);  
175.         X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(pubKeyBytes);  
176.         PublicKey pubKey = keyFactory.generatePublic(x509KeySpec);  
177.   
178.         // 初始化私钥  
179.         byte[] priKeyBytes = decryptBASE64(privateKey);  
180.   
181.         PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(priKeyBytes);  
182.         Key priKey = keyFactory.generatePrivate(pkcs8KeySpec);  
183.   
184.         KeyAgreement keyAgree = KeyAgreement.getInstance(keyFactory  
185.                 .getAlgorithm());  
186.         keyAgree.init(priKey);  
187.         keyAgree.doPhase(pubKey, true);  
188.   
189.         // 生成本地密钥  
190.         SecretKey secretKey = keyAgree.generateSecret(SECRET_ALGORITHM);  
191.   
192.         return secretKey;  
193.     }  
194.   
195.     /** 
196.      * 取得私钥 
197.      *  
198.      * @param keyMap 
199.      * @return 
200.      * @throws Exception 
201.      */  
202.     public static String getPrivateKey(Map<String, Object> keyMap)  
203.             throws Exception {  
204.         Key key = (Key) keyMap.get(PRIVATE_KEY);  
205.   
206.         return encryptBASE64(key.getEncoded());  
207.     }  
208.   
209.     /** 
210.      * 取得公钥 
211.      *  
212.      * @param keyMap 
213.      * @return 
214.      * @throws Exception 
215.      */  
216.     public static String getPublicKey(Map<String, Object> keyMap)  
217.             throws Exception {  
218.         Key key = (Key) keyMap.get(PUBLIC_KEY);  
219.   
220.         return encryptBASE64(key.getEncoded());  
221.     }  
222. }  

import java.security.Key;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.PublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.HashMap;
import java.util.Map;

import javax.crypto.Cipher;
import javax.crypto.KeyAgreement;
import javax.crypto.SecretKey;
import javax.crypto.interfaces.DHPrivateKey;
import javax.crypto.interfaces.DHPublicKey;
import javax.crypto.spec.DHParameterSpec;

/**
 * DH安全编码组件
 * 
 * @author 梁栋
 * @version 1.0
 * @since 1.0
 */
public abstract class DHCoder extends Coder {
	public static final String ALGORITHM = "DH";

	/**
	 * 默认密钥字节数
	 * 
	 * <pre>
	 * DH
	 * Default Keysize 1024  
	 * Keysize must be a multiple of 64, ranging from 512 to 1024 (inclusive).
	 * </pre>
	 */
	private static final int KEY_SIZE = 1024;

	/**
	 * DH加密下需要一种对称加密算法对数据加密，这里我们使用DES，也可以使用其他对称加密算法。
	 */
	public static final String SECRET_ALGORITHM = "DES";
	private static final String PUBLIC_KEY = "DHPublicKey";
	private static final String PRIVATE_KEY = "DHPrivateKey";

	/**
	 * 初始化甲方密钥
	 * 
	 * @return
	 * @throws Exception
	 */
	public static Map<String, Object> initKey() throws Exception {
		KeyPairGenerator keyPairGenerator = KeyPairGenerator
				.getInstance(ALGORITHM);
		keyPairGenerator.initialize(KEY_SIZE);

		KeyPair keyPair = keyPairGenerator.generateKeyPair();

		// 甲方公钥
		DHPublicKey publicKey = (DHPublicKey) keyPair.getPublic();

		// 甲方私钥
		DHPrivateKey privateKey = (DHPrivateKey) keyPair.getPrivate();

		Map<String, Object> keyMap = new HashMap<String, Object>(2);

		keyMap.put(PUBLIC_KEY, publicKey);
		keyMap.put(PRIVATE_KEY, privateKey);
		return keyMap;
	}

	/**
	 * 初始化乙方密钥
	 * 
	 * @param key
	 *            甲方公钥
	 * @return
	 * @throws Exception
	 */
	public static Map<String, Object> initKey(String key) throws Exception {
		// 解析甲方公钥
		byte[] keyBytes = decryptBASE64(key);
		X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);
		KeyFactory keyFactory = KeyFactory.getInstance(ALGORITHM);
		PublicKey pubKey = keyFactory.generatePublic(x509KeySpec);

		// 由甲方公钥构建乙方密钥
		DHParameterSpec dhParamSpec = ((DHPublicKey) pubKey).getParams();

		KeyPairGenerator keyPairGenerator = KeyPairGenerator
				.getInstance(keyFactory.getAlgorithm());
		keyPairGenerator.initialize(dhParamSpec);

		KeyPair keyPair = keyPairGenerator.generateKeyPair();

		// 乙方公钥
		DHPublicKey publicKey = (DHPublicKey) keyPair.getPublic();

		// 乙方私钥
		DHPrivateKey privateKey = (DHPrivateKey) keyPair.getPrivate();

		Map<String, Object> keyMap = new HashMap<String, Object>(2);

		keyMap.put(PUBLIC_KEY, publicKey);
		keyMap.put(PRIVATE_KEY, privateKey);

		return keyMap;
	}

	/**
	 * 加密<br>
	 * 
	 * @param data
	 *            待加密数据
	 * @param publicKey
	 *            甲方公钥
	 * @param privateKey
	 *            乙方私钥
	 * @return
	 * @throws Exception
	 */
	public static byte[] encrypt(byte[] data, String publicKey,
			String privateKey) throws Exception {

		// 生成本地密钥
		SecretKey secretKey = getSecretKey(publicKey, privateKey);

		// 数据加密
		Cipher cipher = Cipher.getInstance(secretKey.getAlgorithm());
		cipher.init(Cipher.ENCRYPT_MODE, secretKey);

		return cipher.doFinal(data);
	}

	/**
	 * 解密<br>
	 * 
	 * @param data
	 *            待解密数据
	 * @param publicKey
	 *            乙方公钥
	 * @param privateKey
	 *            乙方私钥
	 * @return
	 * @throws Exception
	 */
	public static byte[] decrypt(byte[] data, String publicKey,
			String privateKey) throws Exception {

		// 生成本地密钥
		SecretKey secretKey = getSecretKey(publicKey, privateKey);
		// 数据解密
		Cipher cipher = Cipher.getInstance(secretKey.getAlgorithm());
		cipher.init(Cipher.DECRYPT_MODE, secretKey);

		return cipher.doFinal(data);
	}

	/**
	 * 构建密钥
	 * 
	 * @param publicKey
	 *            公钥
	 * @param privateKey
	 *            私钥
	 * @return
	 * @throws Exception
	 */
	private static SecretKey getSecretKey(String publicKey, String privateKey)
			throws Exception {
		// 初始化公钥
		byte[] pubKeyBytes = decryptBASE64(publicKey);

		KeyFactory keyFactory = KeyFactory.getInstance(ALGORITHM);
		X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(pubKeyBytes);
		PublicKey pubKey = keyFactory.generatePublic(x509KeySpec);

		// 初始化私钥
		byte[] priKeyBytes = decryptBASE64(privateKey);

		PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(priKeyBytes);
		Key priKey = keyFactory.generatePrivate(pkcs8KeySpec);

		KeyAgreement keyAgree = KeyAgreement.getInstance(keyFactory
				.getAlgorithm());
		keyAgree.init(priKey);
		keyAgree.doPhase(pubKey, true);

		// 生成本地密钥
		SecretKey secretKey = keyAgree.generateSecret(SECRET_ALGORITHM);

		return secretKey;
	}

	/**
	 * 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());
	}
}

再给出一个测试类：

Java代码  

1. import static org.junit.Assert.*;  
2.   
3. import java.util.Map;  
4.   
5. import org.junit.Test;  
6.   
7. /** 
8.  *  
9.  * @author 梁栋 
10.  * @version 1.0 
11.  * @since 1.0 
12.  */  
13. public class DHCoderTest {  
14.   
15.     @Test  
16.     public void test() throws Exception {  
17.         // 生成甲方密钥对儿  
18.         Map<String, Object> aKeyMap = DHCoder.initKey();  
19.         String aPublicKey = DHCoder.getPublicKey(aKeyMap);  
20.         String aPrivateKey = DHCoder.getPrivateKey(aKeyMap);  
21.   
22.         System.err.println("甲方公钥:\r" + aPublicKey);  
23.         System.err.println("甲方私钥:\r" + aPrivateKey);  
24.           
25.         // 由甲方公钥产生本地密钥对儿  
26.         Map<String, Object> bKeyMap = DHCoder.initKey(aPublicKey);  
27.         String bPublicKey = DHCoder.getPublicKey(bKeyMap);  
28.         String bPrivateKey = DHCoder.getPrivateKey(bKeyMap);  
29.           
30.         System.err.println("乙方公钥:\r" + bPublicKey);  
31.         System.err.println("乙方私钥:\r" + bPrivateKey);  
32.           
33.         String aInput = "abc ";  
34.         System.err.println("原文: " + aInput);  
35.   
36.         // 由甲方公钥，乙方私钥构建密文  
37.         byte[] aCode = DHCoder.encrypt(aInput.getBytes(), aPublicKey,  
38.                 bPrivateKey);  
39.   
40.         // 由乙方公钥，甲方私钥解密  
41.         byte[] aDecode = DHCoder.decrypt(aCode, bPublicKey, aPrivateKey);  
42.         String aOutput = (new String(aDecode));  
43.   
44.         System.err.println("解密: " + aOutput);  
45.   
46.         assertEquals(aInput, aOutput);  
47.   
48.         System.err.println(" ===============反过来加密解密================== ");  
49.         String bInput = "def ";  
50.         System.err.println("原文: " + bInput);  
51.   
52.         // 由乙方公钥，甲方私钥构建密文  
53.         byte[] bCode = DHCoder.encrypt(bInput.getBytes(), bPublicKey,  
54.                 aPrivateKey);  
55.   
56.         // 由甲方公钥，乙方私钥解密  
57.         byte[] bDecode = DHCoder.decrypt(bCode, aPublicKey, bPrivateKey);  
58.         String bOutput = (new String(bDecode));  
59.   
60.         System.err.println("解密: " + bOutput);  
61.   
62.         assertEquals(bInput, bOutput);  
63.     }  
64.   
65. }  

import static org.junit.Assert.*;

import java.util.Map;

import org.junit.Test;

/**
 * 
 * @author 梁栋
 * @version 1.0
 * @since 1.0
 */
public class DHCoderTest {

	@Test
	public void test() throws Exception {
		// 生成甲方密钥对儿
		Map<String, Object> aKeyMap = DHCoder.initKey();
		String aPublicKey = DHCoder.getPublicKey(aKeyMap);
		String aPrivateKey = DHCoder.getPrivateKey(aKeyMap);

		System.err.println("甲方公钥:\r" + aPublicKey);
		System.err.println("甲方私钥:\r" + aPrivateKey);
		
		// 由甲方公钥产生本地密钥对儿
		Map<String, Object> bKeyMap = DHCoder.initKey(aPublicKey);
		String bPublicKey = DHCoder.getPublicKey(bKeyMap);
		String bPrivateKey = DHCoder.getPrivateKey(bKeyMap);
		
		System.err.println("乙方公钥:\r" + bPublicKey);
		System.err.println("乙方私钥:\r" + bPrivateKey);
		
		String aInput = "abc ";
		System.err.println("原文: " + aInput);

		// 由甲方公钥，乙方私钥构建密文
		byte[] aCode = DHCoder.encrypt(aInput.getBytes(), aPublicKey,
				bPrivateKey);

		// 由乙方公钥，甲方私钥解密
		byte[] aDecode = DHCoder.decrypt(aCode, bPublicKey, aPrivateKey);
		String aOutput = (new String(aDecode));

		System.err.println("解密: " + aOutput);

		assertEquals(aInput, aOutput);

		System.err.println(" ===============反过来加密解密================== ");
		String bInput = "def ";
		System.err.println("原文: " + bInput);

		// 由乙方公钥，甲方私钥构建密文
		byte[] bCode = DHCoder.encrypt(bInput.getBytes(), bPublicKey,
				aPrivateKey);

		// 由甲方公钥，乙方私钥解密
		byte[] bDecode = DHCoder.decrypt(bCode, aPublicKey, bPrivateKey);
		String bOutput = (new String(bDecode));

		System.err.println("解密: " + bOutput);

		assertEquals(bInput, bOutput);
	}

}

控制台输出：

Console代码  

1. 甲方公钥:  
2. MIHfMIGXBgkqhkiG9w0BAwEwgYkCQQD8poLOjhLKuibvzPcRDlJtsHiwXt7LzR60ogjzrhYXrgHz  
3. W5Gkfm32NBPF4S7QiZvNEyrNUNmRUb3EPuc3WS4XAkBnhHGyepz0TukaScUUfbGpqvJE8FpDTWSG  
4. kx0tFCcbnjUDC3H9c9oXkGmzLik1Yw4cIGI1TQ2iCmxBblC+eUykAgIBgANDAAJAdAWBVmIzqcko  
5. Ej6qFjLDL2+Y3FPq1iRbnOyOpDj71yKaK1K+FhTv04B0zy4DKcvAASV7/Gv0W+bgqdmffRkqrQ==  
6.   
7. 甲方私钥:  
8. MIHRAgEAMIGXBgkqhkiG9w0BAwEwgYkCQQD8poLOjhLKuibvzPcRDlJtsHiwXt7LzR60ogjzrhYX  
9. rgHzW5Gkfm32NBPF4S7QiZvNEyrNUNmRUb3EPuc3WS4XAkBnhHGyepz0TukaScUUfbGpqvJE8FpD  
10. TWSGkx0tFCcbnjUDC3H9c9oXkGmzLik1Yw4cIGI1TQ2iCmxBblC+eUykAgIBgAQyAjACJRfy1LyR  
11. eHyD+4Hfb+xR0uoIGR1oL9i9Nk6g2AAuaDPgEVWHn+QXID13yL/uDos=  
12.   
13. 乙方公钥:  
14. MIHfMIGXBgkqhkiG9w0BAwEwgYkCQQD8poLOjhLKuibvzPcRDlJtsHiwXt7LzR60ogjzrhYXrgHz  
15. W5Gkfm32NBPF4S7QiZvNEyrNUNmRUb3EPuc3WS4XAkBnhHGyepz0TukaScUUfbGpqvJE8FpDTWSG  
16. kx0tFCcbnjUDC3H9c9oXkGmzLik1Yw4cIGI1TQ2iCmxBblC+eUykAgIBgANDAAJAVEYSfBA+I9nr  
17. dWw3OBv475C+eBrWBBYqt0m6/eu4ptuDQHwV4MmUtKAC2wc2nNrdb1wmBhY1X8RnWkJ1XmdDbQ==  
18.   
19. 乙方私钥:  
20. MIHSAgEAMIGXBgkqhkiG9w0BAwEwgYkCQQD8poLOjhLKuibvzPcRDlJtsHiwXt7LzR60ogjzrhYX  
21. rgHzW5Gkfm32NBPF4S7QiZvNEyrNUNmRUb3EPuc3WS4XAkBnhHGyepz0TukaScUUfbGpqvJE8FpD  
22. TWSGkx0tFCcbnjUDC3H9c9oXkGmzLik1Yw4cIGI1TQ2iCmxBblC+eUykAgIBgAQzAjEAqaZiCdXp  
23. 2iNpdBlHRaO9ir70wo2n32xNlIzIX19VLSPCDdeUWkgRv4CEj/8k+/yd  
24.   
25. 原文: abc   
26. 解密: abc   
27.  ===============反过来加密解密==================   
28. 原文: def   
29. 解密: def   

甲方公钥:
MIHfMIGXBgkqhkiG9w0BAwEwgYkCQQD8poLOjhLKuibvzPcRDlJtsHiwXt7LzR60ogjzrhYXrgHz
W5Gkfm32NBPF4S7QiZvNEyrNUNmRUb3EPuc3WS4XAkBnhHGyepz0TukaScUUfbGpqvJE8FpDTWSG
kx0tFCcbnjUDC3H9c9oXkGmzLik1Yw4cIGI1TQ2iCmxBblC+eUykAgIBgANDAAJAdAWBVmIzqcko
Ej6qFjLDL2+Y3FPq1iRbnOyOpDj71yKaK1K+FhTv04B0zy4DKcvAASV7/Gv0W+bgqdmffRkqrQ==

甲方私钥:
MIHRAgEAMIGXBgkqhkiG9w0BAwEwgYkCQQD8poLOjhLKuibvzPcRDlJtsHiwXt7LzR60ogjzrhYX
rgHzW5Gkfm32NBPF4S7QiZvNEyrNUNmRUb3EPuc3WS4XAkBnhHGyepz0TukaScUUfbGpqvJE8FpD
TWSGkx0tFCcbnjUDC3H9c9oXkGmzLik1Yw4cIGI1TQ2iCmxBblC+eUykAgIBgAQyAjACJRfy1LyR
eHyD+4Hfb+xR0uoIGR1oL9i9Nk6g2AAuaDPgEVWHn+QXID13yL/uDos=

乙方公钥:
MIHfMIGXBgkqhkiG9w0BAwEwgYkCQQD8poLOjhLKuibvzPcRDlJtsHiwXt7LzR60ogjzrhYXrgHz
W5Gkfm32NBPF4S7QiZvNEyrNUNmRUb3EPuc3WS4XAkBnhHGyepz0TukaScUUfbGpqvJE8FpDTWSG
kx0tFCcbnjUDC3H9c9oXkGmzLik1Yw4cIGI1TQ2iCmxBblC+eUykAgIBgANDAAJAVEYSfBA+I9nr
dWw3OBv475C+eBrWBBYqt0m6/eu4ptuDQHwV4MmUtKAC2wc2nNrdb1wmBhY1X8RnWkJ1XmdDbQ==

乙方私钥:
MIHSAgEAMIGXBgkqhkiG9w0BAwEwgYkCQQD8poLOjhLKuibvzPcRDlJtsHiwXt7LzR60ogjzrhYX
rgHzW5Gkfm32NBPF4S7QiZvNEyrNUNmRUb3EPuc3WS4XAkBnhHGyepz0TukaScUUfbGpqvJE8FpD
TWSGkx0tFCcbnjUDC3H9c9oXkGmzLik1Yw4cIGI1TQ2iCmxBblC+eUykAgIBgAQzAjEAqaZiCdXp
2iNpdBlHRaO9ir70wo2n32xNlIzIX19VLSPCDdeUWkgRv4CEj/8k+/yd

原文: abc 
解密: abc 
 ===============反过来加密解密================== 
原文: def 
解密: def

如我所言，甲乙双方在获得对方公钥后可以对发送给对方的数据加密，同时也能对接收到的数据解密，达到了数据安全通信的目的！