JAVA加密算法5

关键字: dh, 公钥, 私钥, 非对称加密, 密钥一致协议
    接下来我们分析DH加密算法，一种适用于网络交互的加密算法。
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！
    当讲到RSA的时候，我们就有一个疑问？如果公钥只能加密，私钥只能解密，但是双方都需要互通加密数据该怎么办？使用DH加密算法！在我看来，这就是他最大的特色！据说该算法源于中国的同余定理——中国馀数定理。

通过java代码实现如下：Coder类见 java加密技术（一）
Java代码
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 
*  
*/ 
public abstract class DHCoder extends Coder {  
    public static final String ALGORITHM = "DH";  
 
    /** 
     * 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 initKey() throws Exception {  
        KeyPairGenerator keyPairGenerator = KeyPairGenerator  
                .getInstance(ALGORITHM);  
        keyPairGenerator.initialize(512);  
 
        KeyPair keyPair = keyPairGenerator.generateKeyPair();  
 
        // 甲方公钥  
        DHPublicKey publicKey = (DHPublicKey) keyPair.getPublic();  
 
        // 甲方私钥  
        DHPrivateKey privateKey = (DHPrivateKey) keyPair.getPrivate();  
 
        Map keyMap = new HashMap(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 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(ALGORITHM);  
        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 keyMap = new HashMap(2);  
 
        keyMap.put(PUBLIC_KEY, publicKey);  
        keyMap.put(PRIVATE_KEY, privateKey);  
 
        return keyMap;  
    }  
 
    /** 
     * 加密
 
     *  
     * @param data 
     * @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 {  
 
        // 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(ALGORITHM);  
        keyAgree.init(priKey);  
        keyAgree.doPhase(pubKey, true);  
 
        // 生成本地密钥  
        SecretKey secretKey = keyAgree.generateSecret(SECRET_ALGORITHM);  
 
        // 数据加密  
        Cipher cipher = Cipher.getInstance(SECRET_ALGORITHM);  
        cipher.init(Cipher.ENCRYPT_MODE, secretKey);  
 
        return cipher.doFinal(data);  
    }  
 
    /** 
     * 解密
 
     *  
     * @param data 
     * @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 {  
 
        // 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(ALGORITHM);  
        keyAgree.init(priKey);  
        keyAgree.doPhase(pubKey, true);  
 
        // 生成本地密钥  
        SecretKey secretKey = keyAgree.generateSecret(SECRET_ALGORITHM);  
 
        // 数据解密  
        Cipher cipher = Cipher.getInstance(SECRET_ALGORITHM);  
        cipher.init(Cipher.DECRYPT_MODE, secretKey);  
 
        return cipher.doFinal(data);  
    }  
 
    /** 
     * 取得私钥 
     *  
     * @param keyMap 
     * @return 
     * @throws Exception 
     */ 
    public static String getPrivateKey(Map 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 keyMap)  
            throws Exception {  
        Key key = (Key) keyMap.get(PUBLIC_KEY);  
 
        return encryptBASE64(key.getEncoded());  
    }  
} 

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
*
*/
public abstract class DHCoder extends Coder {
public static final String ALGORITHM = "DH";

/**
* 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 initKey() throws Exception {
KeyPairGenerator keyPairGenerator = KeyPairGenerator
.getInstance(ALGORITHM);
keyPairGenerator.initialize(512);

KeyPair keyPair = keyPairGenerator.generateKeyPair();

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

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

Map keyMap = new HashMap(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 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(ALGORITHM);
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 keyMap = new HashMap(2);

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

return keyMap;
}

/**
* 加密

*
* @param data
* @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 {

// 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(ALGORITHM);
keyAgree.init(priKey);
keyAgree.doPhase(pubKey, true);

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

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

return cipher.doFinal(data);
}

/**
* 解密

*
* @param data
* @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 {

// 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(ALGORITHM);
keyAgree.init(priKey);
keyAgree.doPhase(pubKey, true);

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

// 数据解密
Cipher cipher = Cipher.getInstance(SECRET_ALGORITHM);
cipher.init(Cipher.DECRYPT_MODE, secretKey);

return cipher.doFinal(data);
}

/**
* 取得私钥
*
* @param keyMap
* @return
* @throws Exception
*/
public static String getPrivateKey(Map 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 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
import static org.junit.Assert.*;  
 
import java.util.Map;  
 
import org.junit.Test;  
 
/** 
*  
*/ 
public class DHCoderTest {  
 
    @Test 
    public void test() throws Exception {  
        // 生成甲方密钥对儿  
        Map 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 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);  
    }  
 
} 

import static org.junit.Assert.*;

import java.util.Map;

import org.junit.Test;

/**
*
*/
public class DHCoderTest {

@Test
public void test() throws Exception {
// 生成甲方密钥对儿
Map 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 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
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  

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