描述
DH算法的作用：
只能用于密鑰的交換诱咏，而不能進(jìn)行消息的加密和解密也殖。
密鑰交換的過(guò)程：
image.png
具體步驟：
1）由消息發(fā)送的一方構(gòu)建密鑰，這里由甲方構(gòu)建密鑰腋颠。
2）由構(gòu)建密鑰的一方向?qū)Ψ焦计涔€繁成，這里由甲方向乙方發(fā)布公鑰。
3）由消息接收的一方通過(guò)對(duì)方公鑰構(gòu)建自身密鑰淑玫，這里由乙方使用甲方公鑰構(gòu)建乙方密鑰朴艰。
4）由消息接收的一方向?qū)Ψ焦计涔€，這里由乙方向甲方公布公鑰混移。
5）甲方根據(jù)自己的私鑰和乙方發(fā)來(lái)的公鑰計(jì)算公共密鑰。
6）乙方根據(jù)自己的私鑰和甲方發(fā)來(lái)的公鑰計(jì)算公共密鑰侮穿。
7）甲乙雙方的公共密鑰應(yīng)該是相等的歌径，通過(guò)該密鑰進(jìn)行后續(xù)的AES加解密運(yùn)算。
乙方構(gòu)建自己密鑰對(duì)的時(shí)候需要使用甲方公鑰作為參數(shù)這是很關(guān)鍵的一點(diǎn)亲茅，如果缺少了這一環(huán)節(jié)則無(wú)法確保甲乙雙方獲得同一個(gè)密鑰回铛，消息加密更無(wú)從談起。
實(shí)現(xiàn)代碼
代碼改進(jìn)：
1 測(cè)試參考代碼時(shí)克锣，解密一直報(bào)錯(cuò)茵肃，借用AES加解密中的代碼進(jìn)行改進(jìn)，能夠進(jìn)行正常的加解密運(yùn)算袭祟。
2 甲乙的公鑰验残、私鑰前半部分是一樣的，后半部分不一樣巾乳，請(qǐng)注意您没。
import java.security.Key;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.NoSuchAlgorithmException;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.SecureRandom;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.HashMap;
import java.util.Map;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.crypto.Cipher;
import javax.crypto.KeyAgreement;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.interfaces.DHPrivateKey;
import javax.crypto.interfaces.DHPublicKey;
import javax.crypto.spec.DHParameterSpec;
import javax.crypto.spec.SecretKeySpec;
public class DHUtils {
/**
* 非對(duì)稱加密密鑰算法
*/
private static final String KEY_ALGORITHM = "DH";
/**
* 本地密鑰算法鸟召，即對(duì)稱加密密鑰算法
* 可選DES、DESede或者AES
*/
private static final String SELECT_ALGORITHM = "AES";
/**
* 默認(rèn)的加密算法
*/
private static final String DEFAULT_CIPHER_ALGORITHM = "AES/ECB/PKCS5Padding";
/**
* 密鑰長(zhǎng)度
*/
private static final int KEY_SIZE = 512;
//公鑰
private static final String PUBLIC_KEY = "DHPublicKey";
//私鑰
private static final String PRIVATE_KEY = "DHPrivateKey";
/**
* 初始化甲方密鑰
* @return Map 甲方密鑰Map
* @throws Exception
*/
public static Map<String, Object> initKey() throws Exception{
//實(shí)例化密鑰對(duì)生成器
KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance(KEY_ALGORITHM);
//初始化密鑰對(duì)生成器
keyPairGenerator.initialize(KEY_SIZE);
//生成密鑰對(duì)
KeyPair keyPair = keyPairGenerator.generateKeyPair();
//甲方公鑰
DHPublicKey publicKey = (DHPublicKey)keyPair.getPublic();
//甲方私鑰
DHPrivateKey privateKey = (DHPrivateKey)keyPair.getPrivate();
//將密鑰對(duì)存儲(chǔ)在Map中
Map<String, Object> keyMap = new HashMap<String, Object>(2);
keyMap.put(PUBLIC_KEY, publicKey);
keyMap.put(PRIVATE_KEY, privateKey);
return keyMap;
}
/**
* 初始化乙方密鑰
* @param key 甲方公鑰
* @return Map 乙方密鑰Map
* @throws Exception
*/
public static Map<String, Object> initKey(byte[] key) throws Exception{
//解析甲方公鑰
//轉(zhuǎn)換公鑰材料
X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(key);
//實(shí)例化密鑰工廠
KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
//產(chǎn)生公鑰
PublicKey pubKey = keyFactory.generatePublic(x509KeySpec);
//由甲方公鑰構(gòu)建乙方密鑰
DHParameterSpec dhParameterSpec = ((DHPublicKey)pubKey).getParams();
//實(shí)例化密鑰對(duì)生成器
KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance(KEY_ALGORITHM);
//初始化密鑰對(duì)生成器
keyPairGenerator.initialize(dhParameterSpec);
//產(chǎn)生密鑰對(duì)
KeyPair keyPair = keyPairGenerator.generateKeyPair();
//乙方公鑰
DHPublicKey publicKey = (DHPublicKey) keyPair.getPublic();
//乙方私約
DHPrivateKey privateKey = (DHPrivateKey) keyPair.getPrivate();
//將密鑰對(duì)存儲(chǔ)在Map中
Map<String, Object> keyMap = new HashMap<String, Object>(2);
keyMap.put(PUBLIC_KEY, publicKey);
keyMap.put(PRIVATE_KEY, privateKey);
return keyMap;
}
/**
* 生成加密秘鑰
*
* @return
*/
private static SecretKeySpec getSecretKey(final byte[] key) {
//返回生成指定算法密鑰生成器的 KeyGenerator 對(duì)象
KeyGenerator kg = null;
try {
kg = KeyGenerator.getInstance(SELECT_ALGORITHM);
//AES 要求密鑰長(zhǎng)度為 128
kg.init(128, new SecureRandom(key));
//生成一個(gè)密鑰
SecretKey secretKey = kg.generateKey();
return new SecretKeySpec(secretKey.getEncoded(), SELECT_ALGORITHM);// 轉(zhuǎn)換為AES專用密鑰
} catch (NoSuchAlgorithmException ex) {
Logger.getLogger(AESUtil.class.getName()).log(Level.SEVERE, null, ex);
}
return null;
}
/**
* 加密
* @param data 待加密數(shù)據(jù)
* @param key 密鑰
* @return byte[] 加密數(shù)據(jù)
* @throws Exception
*/
public static byte[] encrypt(byte[] data, byte[] key) throws Exception{
try {
Cipher cipher = Cipher.getInstance(DEFAULT_CIPHER_ALGORITHM);// 創(chuàng)建密碼器
byte[] byteContent = data;
cipher.init(Cipher.ENCRYPT_MODE, getSecretKey(key));// 初始化為加密模式的密碼器
byte[] result = cipher.doFinal(byteContent);// 加密
return result;
// return Base64Utils.encode(result);//通過(guò)Base64轉(zhuǎn)碼返回
} catch (Exception ex) {
Logger.getLogger(AESUtil.class.getName()).log(Level.SEVERE, null, ex);
}
return null;
}
/**
* 解密
* @param data 待解密數(shù)據(jù)
* @param key 密鑰
* @return byte[] 解密數(shù)據(jù)
* @throws Exception
*/
public static byte[] decrypt(byte[] data, byte[] key) throws Exception{
try {
//實(shí)例化
Cipher cipher = Cipher.getInstance(DEFAULT_CIPHER_ALGORITHM);
//使用密鑰初始化氨鹏，設(shè)置為解密模式
cipher.init(Cipher.DECRYPT_MODE, getSecretKey(key));
//執(zhí)行操作
byte[] result = cipher.doFinal(data);
return result;
} catch (Exception ex) {
Logger.getLogger(AESUtil.class.getName()).log(Level.SEVERE, null, ex);
}
return null;
}
/**
* 構(gòu)建密鑰
* @param publicKey 公鑰
* @param privateKey 私鑰
* @return byte[] 本地密鑰
* @throws Exception
*/
public static byte[] getSecretKey(byte[] publicKey, byte[] privateKey) throws Exception{
//實(shí)例化密鑰工廠
KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
//初始化公鑰
//密鑰材料轉(zhuǎn)換
X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(publicKey);
//產(chǎn)生公鑰
PublicKey pubKey = keyFactory.generatePublic(x509KeySpec);
//初始化私鑰
//密鑰材料轉(zhuǎn)換
PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(privateKey);
//產(chǎn)生私鑰
PrivateKey priKey = keyFactory.generatePrivate(pkcs8KeySpec);
//實(shí)例化
KeyAgreement keyAgree = KeyAgreement.getInstance(keyFactory.getAlgorithm());
//初始化
keyAgree.init(priKey);
keyAgree.doPhase(pubKey, true);
//生成本地密鑰
SecretKey secretKey = keyAgree.generateSecret(SELECT_ALGORITHM);
return secretKey.getEncoded();
}
/**
* 取得私鑰
* @param keyMap 密鑰Map
* @return byte[] 私鑰
* @throws Exception
*/
public static byte[] getPrivateKey(Map<String, Object> keyMap) throws Exception{
Key key = (Key) keyMap.get(PRIVATE_KEY);
return key.getEncoded();
}
/**
* 取得公鑰
* @param keyMap 密鑰Map
* @return byte[] 公鑰
* @throws Exception
*/
public static byte[] getPublicKey(Map<String, Object> keyMap) throws Exception{
Key key = (Key) keyMap.get(PUBLIC_KEY);
return key.getEncoded();
}
/**
* 主方法
* @param args
* @throws Exception
*/
public static void main(String[] args) throws Exception {
//甲方公鑰
byte[] publicKey1;
//甲方私鑰
byte[] privateKey1;
//甲方本地密鑰
byte[] key1;
//乙方公鑰
byte[] publicKey2;
//乙方私鑰
byte[] privateKey2;
//乙方本地密鑰
byte[] key2;
//初始化密鑰
//生成甲方密鑰對(duì)
Map<String, Object> keyMap1 = DHUtils.initKey();
publicKey1 = DHUtils.getPublicKey(keyMap1);
privateKey1 = DHUtils.getPrivateKey(keyMap1);
System.out.println("甲方公鑰:\n" + Base64Utils.encode(publicKey1));
System.out.println("甲方私鑰:\n" + Base64Utils.encode(privateKey1));
//由甲方公鑰產(chǎn)生乙方本地密鑰對(duì)
Map<String, Object> keyMap2 = DHUtils.initKey(publicKey1);
publicKey2 = DHUtils.getPublicKey(keyMap2);
privateKey2 = DHUtils.getPrivateKey(keyMap2);
System.out.println("乙方公鑰:\n" + Base64Utils.encode(publicKey2));
System.out.println("乙方私鑰:\n" + Base64Utils.encode(privateKey2));
key1 = DHUtils.getSecretKey(publicKey2, privateKey1);
System.out.println("甲方本地密鑰:\n" + Base64Utils.encode(key1));
key2 = DHUtils.getSecretKey(publicKey1, privateKey2);
System.out.println("乙方本地密鑰:\n" + Base64Utils.encode(key2));
System.out.println();
System.out.println("===甲方向乙方發(fā)送加密數(shù)據(jù)===");
String input1 = "求知若饑欧募，虛心若愚。";
System.out.println("原文:\n" + input1);
System.out.println("---使用甲方本地密鑰對(duì)數(shù)據(jù)進(jìn)行加密---");
//使用甲方本地密鑰對(duì)數(shù)據(jù)加密
byte[] encode1 = DHUtils.encrypt(input1.getBytes(), key1);
System.out.println("加密:\n" + Base64Utils.encode(encode1));
System.out.println("---使用乙方本地密鑰對(duì)數(shù)據(jù)庫(kù)進(jìn)行解密---");
//使用乙方本地密鑰對(duì)數(shù)據(jù)進(jìn)行解密
byte[] decode1 = DHUtils.decrypt(encode1, key2);
String output1 = new String(decode1);
System.out.println("解密:\n" + output1);
System.out.println("/~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~..~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~/");
System.out.println("===乙方向甲方發(fā)送加密數(shù)據(jù)===");
String input2 = "好好學(xué)習(xí)仆抵，天天向上跟继。";
System.out.println("原文:\n" + input2);
System.out.println("---使用乙方本地密鑰對(duì)數(shù)據(jù)進(jìn)行加密---");
//使用乙方本地密鑰對(duì)數(shù)據(jù)進(jìn)行加密
byte[] encode2 = DHUtils.encrypt(input2.getBytes(), key2);
System.out.println("加密:\n" + Base64Utils.encode(encode2));
System.out.println("---使用甲方本地密鑰對(duì)數(shù)據(jù)進(jìn)行解密---");
//使用甲方本地密鑰對(duì)數(shù)據(jù)進(jìn)行解密
byte[] decode2 = DHUtils.decrypt(encode2, key1);
String output2 = new String(decode2);
System.out.println("解密:\n" + output2);
}
}
程序運(yùn)行結(jié)果
甲方公鑰:
MIHfMIGXBgkqhkiG9w0BAwEwgYkCQQD8poLOjhLKuibvzPcRDlJtsHiwXt7LzR60ogjzrhYXrgHzW5Gkfm32NBPF4S7QiZvNEyrNUNmRUb3EPuc3WS4XAkBnhHGyepz0TukaScUUfbGpqvJE8FpDTWSGkx0tFCcbnjUDC3H9c9oXkGmzLik1Yw4cIGI1TQ2iCmxBblC+eUykAgIBgANDAAJASSv0Yr3ZAPLjx4v3AeYrT9Oi+jOxRjg79LsNDnMcaSDj5x4077FtIilCMDizonijx7SPf9R0JFEvWtxxQaCfVg==
甲方私鑰:
MIHSAgEAMIGXBgkqhkiG9w0BAwEwgYkCQQD8poLOjhLKuibvzPcRDlJtsHiwXt7LzR60ogjzrhYXrgHzW5Gkfm32NBPF4S7QiZvNEyrNUNmRUb3EPuc3WS4XAkBnhHGyepz0TukaScUUfbGpqvJE8FpDTWSGkx0tFCcbnjUDC3H9c9oXkGmzLik1Yw4cIGI1TQ2iCmxBblC+eUykAgIBgAQzAjEAuHDrheHknkdkNAIKDKkZ/qy/alDf5Vodzex7oJbndsvmVJSnhnq5+gNP4fxsuLvU
乙方公鑰:
MIHfMIGXBgkqhkiG9w0BAwEwgYkCQQD8poLOjhLKuibvzPcRDlJtsHiwXt7LzR60ogjzrhYXrgHzW5Gkfm32NBPF4S7QiZvNEyrNUNmRUb3EPuc3WS4XAkBnhHGyepz0TukaScUUfbGpqvJE8FpDTWSGkx0tFCcbnjUDC3H9c9oXkGmzLik1Yw4cIGI1TQ2iCmxBblC+eUykAgIBgANDAAJAdi+qTwkOw++UCM8jY/Ysn9t6+nXBPrqUu5hwjUihkDrChNEzQ6aJd7ES4Fu9HQe8nlQ/mjUMoecKKqTbq88oxw==
乙方私鑰:
MIHSAgEAMIGXBgkqhkiG9w0BAwEwgYkCQQD8poLOjhLKuibvzPcRDlJtsHiwXt7LzR60ogjzrhYXrgHzW5Gkfm32NBPF4S7QiZvNEyrNUNmRUb3EPuc3WS4XAkBnhHGyepz0TukaScUUfbGpqvJE8FpDTWSGkx0tFCcbnjUDC3H9c9oXkGmzLik1Yw4cIGI1TQ2iCmxBblC+eUykAgIBgAQzAjEA9ELoy2WZgjvLCizKUiH63fflmUa8npnoRf6utra5z6YPxQ/Skof6cwv7Zpaog/T+
甲方本地密鑰:
z/lFVca4FK9zer3Qr8FwZ1rqgZWBW9euVHQq1CRUpVo=
乙方本地密鑰:
z/lFVca4FK9zer3Qr8FwZ1rqgZWBW9euVHQq1CRUpVo=
===甲方向乙方發(fā)送加密數(shù)據(jù)===
原文:
求知若饑，虛心若愚镣丑。
---使用甲方本地密鑰對(duì)數(shù)據(jù)進(jìn)行加密---
加密:
V4BnmieIqjZrmC8E4iPWaCetdwT9FbZ/Z4PoIRIwh1o=
---使用乙方本地密鑰對(duì)數(shù)據(jù)庫(kù)進(jìn)行解密---
解密:
求知若饑舔糖，虛心若愚。
/~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~..~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~.~/
===乙方向甲方發(fā)送加密數(shù)據(jù)===
原文:
好好學(xué)習(xí)传轰，天天向上剩盒。
---使用乙方本地密鑰對(duì)數(shù)據(jù)進(jìn)行加密---
加密:
iDkd+sLkYEehzuHVEq1MC9EKJuG+MDRHWxS5c7V0BHU=
---使用甲方本地密鑰對(duì)數(shù)據(jù)進(jìn)行解密---
解密:
好好學(xué)習(xí)，天天向上慨蛙。
參考
密鑰交換算法DH（Java實(shí)現(xiàn)）
https://blog.csdn.net/ldld1717/article/details/53116048
JAVA加密解密之DH（Diffie-Hellman）算法
https://blog.csdn.net/jianggujin/article/details/50537103
