密钥长度：512-1024位
密钥默认长度：1024位
工作模式：无
填充方式：无
JDK6.0提供了实现
package test;
import java.security.Key;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.PublicKey;
import java.security.PrivateKey;
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;
import javax.crypto.spec.SecretKeySpec;
public abstract class DHCoder {
/**
* 非对称加密密钥算法
*/
public static final String KEY_ALGORITHM = "DH";
/**
* 本地密钥算法，即对称加密密钥算法，可选DES、DESede和AES算法
*/
public static final String SECRET_KEY_ALGORITHM = "AES";
/**
* 默认密钥长度
*
* DH算法默认密钥长度为1024 密钥长度必须是64的倍数，其范围在512到1024位之间。
*/
private static final int KEY_SIZE = 512;
/**
* 公钥
*/
private static final String PUBLIC_KEY = "DHPublicKey";
/**
* 私钥
*/
private static final String PRIVATE_KEY = "DHPrivateKey";
/**
* 初始化甲方密钥
*
* @return Map 甲方密钥Map
* @throws Exception
*/
public static Map<String, Object> initKey() throws Exception {
// 实例化密钥对生成器
KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance(KEY_ALGORITHM);
// 初始化密钥对生成器
keyPairGenerator.initialize(KEY_SIZE);
// 生成密钥对
KeyPair keyPair = keyPairGenerator.generateKeyPair();
// 甲方公钥
DHPublicKey publicKey = (DHPublicKey) keyPair.getPublic();
// 甲方私钥
DHPrivateKey privateKey = (DHPrivateKey) keyPair.getPrivate();
// 将密钥对存储在Map中
Map<String, Object> keyMap = new HashMap<String, Object>(2);
keyMap.put(PUBLIC_KEY, publicKey);
keyMap.put(PRIVATE_KEY, privateKey);
return keyMap;
}
/**
* 初始化乙方密钥
*
* @param key
*
甲方公钥
* @return Map 乙方密钥Map
* @throws Exception
*/
public static Map<String, Object> initKey(byte[] key) throws Exception {
// 解析甲方公钥
// 转换公钥材料
X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(key);
// 实例化密钥工厂
KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
// 产生公钥
PublicKey pubKey = keyFactory.generatePublic(x509KeySpec);
// 由甲方公钥构建乙方密钥
DHParameterSpec dhParamSpec = ((DHPublicKey) pubKey).getParams();
// 实例化密钥对生成器
KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance(keyFactory.getAlgorithm());
// 初始化密钥对生成器
keyPairGenerator.initialize(dhParamSpec);
// 产生密钥对
KeyPair keyPair = keyPairGenerator.generateKeyPair();
// 乙方公钥
DHPublicKey publicKey = (DHPublicKey) keyPair.getPublic();
// 乙方私钥
DHPrivateKey privateKey = (DHPrivateKey) keyPair.getPrivate();
// 将密钥对存储在Map中
Map<String, Object> keyMap = new HashMap<String, Object>(2);
keyMap.put(PUBLIC_KEY, publicKey);
keyMap.put(PRIVATE_KEY, privateKey);
return keyMap;
}
/**
* 构建密钥
*
* @param publicKey
*
公钥
* @param privateKey
*
私钥
* @return byte[] 本地密钥
* @throws Exception
*/
public static byte[] getSecretKey(byte[] publicKey, byte[] privateKey)
throws Exception {
// 实例化密钥工厂
KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
// 初始化公钥
// 密钥材料转换
X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(publicKey);
// 产生公钥
PublicKey pubKey = keyFactory.generatePublic(x509KeySpec);
// 初始化私钥
// 密钥材料转换
PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(privateKey);
// 产生私钥
PrivateKey priKey = keyFactory.generatePrivate(pkcs8KeySpec);
// 实例化
KeyAgreement keyAgree = KeyAgreement.getInstance(keyFactory
.getAlgorithm());
// 初始化
keyAgree.init(priKey);
keyAgree.doPhase(pubKey, true);
// 生成本地密钥
SecretKey secretKey = keyAgree.generateSecret(SECRET_KEY_ALGORITHM);
return secretKey.getEncoded();
}
}
