數字簽字RSA

package 數字簽字;

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.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;

import org.apache.commons.codec.binary.Hex;



public class RSA {
private static String src="imooc";

    public static void main(String[] args) {
        jdkRSA();
    }
    /*
     * 
     * 私鑰簽名  公鑰認證
     */

    public static void jdkRSA(){
         //1初始化祕鑰
        try {
            KeyPairGenerator keyPairGenerator=KeyPairGenerator.getInstance("RSA");
            keyPairGenerator.initialize(512);
            KeyPair keyPair=keyPairGenerator.generateKeyPair();
            RSAPublicKey rsaPublicKey=(RSAPublicKey) keyPair.getPublic();
            RSAPrivateKey rsaPrivateKey=(RSAPrivateKey) keyPair.getPrivate();


            //2執行簽名
            PKCS8EncodedKeySpec pkcs8=new PKCS8EncodedKeySpec(rsaPrivateKey.getEncoded());
            KeyFactory keyFactory=KeyFactory.getInstance("RSA");
            PrivateKey privateKey=keyFactory.generatePrivate(pkcs8);
            Signature signature=Signature.getInstance("MD5withRSA");
            //初始化signature
             signature.initSign(privateKey);
            signature.update(src.getBytes());
            byte[]result=signature.sign();
            System.out.println("jdk RSA:"+Hex.encodeHexString(result));
            //驗證簽名
            X509EncodedKeySpec x509EncodedKeySpec=new X509EncodedKeySpec(rsaPublicKey.getEncoded());
            KeyFactory keyFactory2=KeyFactory.getInstance("RSA");
            PublicKey publicKey=keyFactory2.generatePublic(x509EncodedKeySpec);
            signature=Signature.getInstance("MD5withRSA");
            signature.initVerify(publicKey);
            signature.update(src.getBytes());
            boolean bool=signature.verify(result);
            System.out.println("jdk RSA Verify"+bool);

        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }


    }

}