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);
}
}
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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));
}
}
}
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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
