java-信息安全（十）-数字签名算法DSA
概述
信息安全基本概念：
- DSA算法（Digital Signature Algorithm，数据签名算法）
DSA
Digital Signature Algorithm (DSA)是Schnorr和ElGamal签名算法的变种，被美国NIST作为DSfS(DigitalSignature Standard)。
简单的说，这是一种更高级的验证方式，用作数字签名。不单单只有公钥、私钥，还有数字签名。私钥加密生成数字签名，公钥验证数据及签名。如果数据和签名不匹配则认为验证失败！数字签名的作用就是校验数据在传输过程中不被修改。数字签名，是单向加密的升级！
算法分类
| 算法 | 密钥长度 | 默认长度 | 签名长度 | 实现的方 |
| SHA1withDSA | 512-65536 （64的整数倍） |
1024 | 同密钥 | JDK |
| SHA224withDSA | 同上 | 1024 | 同密钥 | BC |
| SHA256withDSA | ... | 1024 | 同密钥 | BC |
| SHA384withDSA | ... | 1024 | 同密钥 | BC |
| SHA512withDSA | ... | 1024 | 同密钥 | BC |
签名示例
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.Signature;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import com.sun.org.apache.xerces.internal.impl.dv.util.HexBin;
import sun.security.provider.DSAPrivateKey;
import sun.security.provider.DSAPublicKey;
public class DSA {
private static String src = "dsa security";
public static void main(String[] args) {
jdkDSA();
}
public static void jdkDSA(){
try {
//1.初始化密钥
KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("DSA");
keyPairGenerator.initialize(512);
KeyPair keyPair = keyPairGenerator.generateKeyPair();
DSAPublicKey dsaPublicKey = (DSAPublicKey)keyPair.getPublic();
DSAPrivateKey dsaPrivateKey = (DSAPrivateKey)keyPair.getPrivate();
//2.执行签名
PKCS8EncodedKeySpec pkcs8EncodedKeySpec = new PKCS8EncodedKeySpec(dsaPrivateKey.getEncoded());
KeyFactory keyFactory = KeyFactory.getInstance("DSA");
PrivateKey privateKey = keyFactory.generatePrivate(pkcs8EncodedKeySpec);
Signature signature = Signature.getInstance("SHA1withDSA");
signature.initSign(privateKey);
signature.update(src.getBytes());
byte[] res = signature.sign();
System.out.println("签名："+HexBin.encode(res));
//3.验证签名
X509EncodedKeySpec x509EncodedKeySpec = new X509EncodedKeySpec(dsaPublicKey.getEncoded());
keyFactory = KeyFactory.getInstance("DSA");
PublicKey publicKey = keyFactory.generatePublic(x509EncodedKeySpec);
signature = Signature.getInstance("SHA1withDSA");
signature.initVerify(publicKey);
signature.update(src.getBytes());
boolean bool = signature.verify(res);
System.out.println("验证："+bool);
} catch (Exception e) {
e.printStackTrace();
}
}
}
示例代码
package com.jd.order.util.encryption;
import java.security.Key;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.SecureRandom;
import java.security.Signature;
import java.security.interfaces.DSAPrivateKey;
import java.security.interfaces.DSAPublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.HashMap;
import java.util.Map;
import org.apache.commons.codec.binary.Base64;
/**
* DSA数字签名组件
*
* @author 木子旭
* @since 2017年3月17日上午10:37:30
* @version %I%,%G%
*/
public class DSACoder {
public static final String ALGORITHM = "DSA";
/**
* 默认密钥字节数
*
* <pre>
* DSA
* Default Keysize 1024
* Keysize must be a multiple of 64, ranging from 512 to 1024 (inclusive).
* </pre>
*/
private static final int KEY_SIZE = 1024;
/**
* 默认种子
*/
private static final String DEFAULT_SEED = "0f22507a10bbddd07d8a3082122966e3";
private static final String PUBLIC_KEY = "DSAPublicKey";
private static final String PRIVATE_KEY = "DSAPrivateKey";
/**
* 用私钥对信息生成数字签名
*
* @param data
* 加密数据
* @param privateKey
* 私钥
*
* @return
* @throws Exception
*/
public static String sign(byte[] data, String privateKey) throws Exception {
// 解密由base64编码的私钥
byte[] keyBytes = decryptBASE64(privateKey);
// 构造PKCS8EncodedKeySpec对象
PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
// KEY_ALGORITHM 指定的加密算法
KeyFactory keyFactory = KeyFactory.getInstance(ALGORITHM);
// 取私钥匙对象
PrivateKey priKey = keyFactory.generatePrivate(pkcs8KeySpec);
// 用私钥对信息生成数字签名
Signature signature = Signature.getInstance(keyFactory.getAlgorithm());
signature.initSign(priKey);
signature.update(data);
return encryptBASE64(signature.sign());
}
/**
* 校验数字签名
*
* @param data
* 加密数据
* @param publicKey
* 公钥
* @param sign
* 数字签名
*
* @return 校验成功返回true 失败返回false
* @throws Exception
*
*/
public static boolean verify(byte[] data, String publicKey, String sign)
throws Exception {
// 解密由base64编码的公钥
byte[] keyBytes = decryptBASE64(publicKey);
// 构造X509EncodedKeySpec对象
X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);
// ALGORITHM 指定的加密算法
KeyFactory keyFactory = KeyFactory.getInstance(ALGORITHM);
// 取公钥匙对象
PublicKey pubKey = keyFactory.generatePublic(keySpec);
Signature signature = Signature.getInstance(keyFactory.getAlgorithm());
signature.initVerify(pubKey);
signature.update(data);
// 验证签名是否正常
return signature.verify(decryptBASE64(sign));
}
/**
* 生成密钥
*
* @param seed
* 种子
* @return 密钥对象
* @throws Exception
*/
public static Map<String, Object> initKey(String seed) throws Exception {
KeyPairGenerator keygen = KeyPairGenerator.getInstance(ALGORITHM);
// 初始化随机产生器
SecureRandom secureRandom = new SecureRandom();
secureRandom.setSeed(seed.getBytes());
keygen.initialize(KEY_SIZE, secureRandom);
KeyPair keys = keygen.genKeyPair();
DSAPublicKey publicKey = (DSAPublicKey) keys.getPublic();
DSAPrivateKey privateKey = (DSAPrivateKey) keys.getPrivate();
Map<String, Object> map = new HashMap<String, Object>(2);
map.put(PUBLIC_KEY, publicKey);
map.put(PRIVATE_KEY, privateKey);
return map;
}
/**
* 默认生成密钥
*
* @return 密钥对象
* @throws Exception
*/
public static Map<String, Object> initKey() throws Exception {
return initKey(DEFAULT_SEED);
}
/**
* 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());
}
public static byte[] decryptBASE64(String data) {
return Base64.decodeBase64(data);
}
public static String encryptBASE64(byte[] data) {
return new String(Base64.encodeBase64(data));
}
}
测试代码
package com.jd.order.util.encryption;
import static org.junit.Assert.assertTrue;
import java.util.Map;
import org.junit.Test;
public class DSACoderTest {
@Test
public void test() throws Exception {
String inputStr = "abc";
byte[] data = inputStr.getBytes();
// 构建密钥
Map<String, Object> keyMap = DSACoder.initKey();
// 获得密钥
String publicKey = DSACoder.getPublicKey(keyMap);
String privateKey = DSACoder.getPrivateKey(keyMap);
System.err.println("公钥:\r" + publicKey);
System.err.println("私钥:\r" + privateKey);
// 产生签名
String sign = DSACoder.sign(data, privateKey);
System.err.println("签名:\r" + sign);
// 验证签名
boolean status = DSACoder.verify(data, publicKey, sign);
System.err.println("状态:\r" + status);
assertTrue(status);
}
}
输出
公钥: 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 私钥: MIIBTAIBADCCASwGByqGSM44BAEwggEfAoGBAP1/U4EddRIpUt9KnC7s5Of2EbdSPO9EAMMeP4C2USZpRV1AIlH7WT2NWPq/xfW6MPbLm1Vs14E7gB00b/JmYLdrmVClpJ+f6AR7ECLCT7up1/63xhv4O1fnxqimFQ8E+4P208UewwI1VBNaFpEy9nXzrith1yrv8iIDGZ3RSAHHAhUAl2BQjxUjC8yykrmCouuEC/BYHPUCgYEA9+GghdabPd7LvKtcNrhXuXmUr7v6OuqC+VdMCz0HgmdRWVeOutRZT+ZxBxCBgLRJFnEj6EwoFhO3zwkyjMim4TwWeotUfI0o4KOuHiuzpnWRbqN/C/ohNWLx+2J6ASQ7zKTxvqhRkImog9/hWuWfBpKLZl6Ae1UlZAFMO/7PSSoEFwIVAIegLUtmm2oQKQJTOiLugHTSjl/q 签名: MCwCFGQHO9AO70cMxFTPeYqAwq7B7OFxAhRGC8A6YwFFZSfuVTAfleDof/yGug== 状态: true
参考地址：
http://snowolf.iteye.com/blog/382749
