JAVA加密解密之DSA（Digital Signature Algorithm）算法

DSA算法简介

DSA-Digital Signature Algorithm是Schnorr和ElGamal签名算法的变种，被美国NIST作为DSS(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！

DSA算法实现

package com.jianggujin.codec;

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;

/**
* DSA
*
* @author jianggujin
*
*/
public class HQDSA
{
private static HQDSA dsa = new HQDSA();

public static HQDSA getInstance()
{
return dsa;
}

private HQDSA()
{
}

/**
* DSA签名算法
*
* @author jianggujin
*
*/
public static enum HQDSASignatureAlgorithm
{

DSA("DSA"), SHA1withDSA("SHA1withDSA"), SHA224withDSA("SHA224withDSA"), SHA256withDSA("SHA256withDSA");
private String name;

private HQDSASignatureAlgorithm(String name)
{
this.name = name;
}

public String getName()
{
return this.name;
}
}

public static final String ALGORITHM = "DSA";

public byte[] sign(byte[] data, byte[] privateKey, HQDSASignatureAlgorithm signatureAlgorithm) throws Exception
{
return sign(data, privateKey, signatureAlgorithm.getName());
}

public byte[] sign(byte[] data, byte[] privateKey, String signatureAlgorithm) throws Exception
{
PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(privateKey);

KeyFactory keyFactory = KeyFactory.getInstance(ALGORITHM);

PrivateKey priKey = keyFactory.generatePrivate(pkcs8KeySpec);

Signature signature = Signature.getInstance(signatureAlgorithm);
signature.initSign(priKey);
signature.update(data);
return signature.sign();
}

public boolean verify(byte[] data, byte[] publicKey, byte[] sign, HQDSASignatureAlgorithm signatureAlgorithm)
throws Exception
{
return verify(data, publicKey, sign, signatureAlgorithm.getName());
}

public boolean verify(byte[] data, byte[] publicKey, byte[] sign, String signatureAlgorithm) throws Exception
{
X509EncodedKeySpec keySpec = new X509EncodedKeySpec(publicKey);

KeyFactory keyFactory = KeyFactory.getInstance(ALGORITHM);

PublicKey pubKey = keyFactory.generatePublic(keySpec);

Signature signature = Signature.getInstance(signatureAlgorithm);
signature.initVerify(pubKey);
signature.update(data);

return signature.verify(sign);
}

/**
* 初始化密钥
*
* @return
*/
public HQKeyPair initKey() throws Exception
{
return initKey(1024);
}

/**
* 初始化密钥
*
* @param keySize
* @return
*/
public HQKeyPair initKey(int keySize) throws Exception
{
KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance(ALGORITHM);
keyPairGen.initialize(1024);
KeyPair keyPair = keyPairGen.generateKeyPair();
return new HQKeyPair(keyPair);
}
}

测试代码：

import org.junit.Test;

import com.jianggujin.codec.HQBase64;
import com.jianggujin.codec.HQDSA;
import com.jianggujin.codec.HQDSA.HQDSASignatureAlgorithm;
import com.jianggujin.codec.HQKeyPair;

public class DSATest
{
HQDSA dsa = HQDSA.getInstance();
HQBase64 base64 = HQBase64.getInstance();

@Test
public void encode() throws Exception
{
byte[] data = "jianggujin".getBytes();
HQKeyPair keyPair = dsa.initKey();
HQDSASignatureAlgorithm[] algorithms = HQDSASignatureAlgorithm.values();
for (HQDSASignatureAlgorithm algorithm : algorithms)
{
System.err.println("=========================================");
System.err.println(algorithm);
byte[] sign = dsa.sign(data, keyPair.getPrivateKey(), algorithm);
System.err.println("签名:" + base64.encodeToString(sign));
System.err.println("验签:" + dsa.verify(data, keyPair.getPublicKey(), sign, algorithm));
}
}
}

测试结果：

=========================================

DSA

签名:MC0CFQCRt2xFSIBJ/XSPHGYmSHhTOCjkwAIUSn8r6egiLg/d+Puq/AjE+IPGEvE=

验签:true

=========================================

SHA1withDSA

签名:MCwCFGOsJKBaGWXR5QA+YK3Z/QQ2li/LAhRQLQM3BFmM9B2jjyxrBUaO11xqVA==

验签:true

=========================================

SHA224withDSA

签名:MCwCFANthkgvsQ/zMFDUlkfMiv386bszAhRJCOvQI5LKRuvZdoyOOomNy2R7RA==

验签:true

=========================================

SHA256withDSA

签名:MCwCFH/IFt1WfO/y6cRAX2GHaA0PkqoSAhRVHgecDEVkXmuZwePvfeLuU/3lqA==

验签:true