数字签名算法--2.DSA

package Imooc;


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.Signature;
import java.security.interfaces.DSAPrivateKey;
import java.security.interfaces.DSAPublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;


import com.sun.org.apache.xerces.internal.impl.dv.util.HexBin;


public class ImoocDSA {


private static String src ="imooc security dsa";
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[] result = signature.sign();
System.out.println("jdk dsa sign :" + HexBin.encode(result));
//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(result);
System.out.println("jdk dsa verify : "+ bool );
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}


}
}