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前段时间需要用到这方面的技术,写了几个例子,不加文字说明,只贴代码
package demo.encrypt;

import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

/**
 * 
 * 摘要加密。检验信息完整性 目前广泛使用的算法有MD4、MD5、SHA-1
 * 
@author peidw 2008-03-02
 *
 
*/
public class MessageDigestExample {
/**
 * 信息摘要完整性加密
 * 
 
*/
    
    
/**
     * 单一摘要算法,不使用密码
     * 
@param args
     * 
@throws UnsupportedEncodingException 
     * 
@throws NoSuchAlgorithmException 
     
*/
    
public static void main(String[] args) throws UnsupportedEncodingException, NoSuchAlgorithmException {
        String str
="www.17lotto.com";  //要加密的字符串
        byte[] bstr=str.getBytes("utf-8");
        MessageDigest messageDigest
=MessageDigest.getInstance("SHA-1"); //获取算法
        System.out.println("\n"+messageDigest.getProvider().getInfo());
        System.out.println(
"加密前:\n "+new String(bstr));
        
        messageDigest.update(bstr);
        System.out.println(
"\n加密后结果:");
        System.out.println(
new String(messageDigest.digest(),"utf-8"));

    }

}


package demo.encrypt;

import java.io.*;
import java.security.Key;
import java.security.NoSuchAlgorithmException;

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;

/**
 * 私钥加密,也称对称性密码,加/解密双方共享同一密钥
 * 
 * 
@author peidw
 *
 
*/

public class PrivateExample {
    
/**
     * 加必解密例子
     * 
@throws Exception
     
*/
    
public void deendemo()throws Exception{
        String str
="www.17lotto.com";  //要加密的字符串
        byte[] bstr=str.getBytes("utf-8");
        
//产生密钥
        KeyGenerator keyGen=KeyGenerator.getInstance("AES");
        keyGen.init(
128);
        
        Key key
=keyGen.generateKey();
        
//密钥保存
        File fkey=new File("f:\\key.obj");
        OutputStream os
=new FileOutputStream(fkey);
        os.write(key.getEncoded());
        os.flush();
        os.close();
        
//密钥保存问题
        
        
//获得一个私鈅加密类Cipher,ECB是加密方式,PKCS5Padding是填充方法
        Cipher cipher=Cipher.getInstance("AES/ECB/PKCS5Padding");
        System.out.println(
"\n"+cipher.getProvider().getInfo());
        
        
//使用私鈅加密
        cipher.init(Cipher.ENCRYPT_MODE,key);
        
byte[] cipherText=cipher.doFinal(bstr);
        
//密文保存
        File cryptograph=new File("f:\\cryptograph.obj");
        OutputStream cos
=new FileOutputStream(cryptograph);
        cos.write(cipherText);
        cos.flush();
        cos.close();
        
        System.out.println(
"Finish encryption:");
        System.out.println(
new String(cipherText,"utf-8"));

        System.out.println(
"\nStart decryption:");
        cipher.init(Cipher.DECRYPT_MODE,key);
        
byte[] newPlainText=cipher.doFinal(cipherText);
        System.out.println(
"Finish decryption:");

        System.out.println(
new String(newPlainText,"utf-8"));
        
    }
    
    
/**
     * 从文件加载密钥和密文进行解密例子(新jdk不懂怎么加载)
     * 
@throws Exception
     
*/
    
public void decryptionFromFile()throws Exception{
        KeyGenerator keyGen
=KeyGenerator.getInstance("AES");
        
    }
    
    
/**
     * 
@param args
     * 
@throws Exception 
     
*/
    
public static void main(String[] args) throws Exception {
        PrivateExample pe
=new PrivateExample();
        pe.deendemo();
    }

}


package demo.encrypt;

import java.io.*;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;

import javax.crypto.Cipher;

/**
 *  非对称性加密,也叫公钥加密 产开两个密钥(私钥,公钥)私钥加密只有公钥才能解样,同时公钥加密只有私钥能解开.
 *  目前JDK5提供的RSA算法
 * 
@author peidw
 *
 
*/
public class PublicExample {
    
/**
     * 加密解密例子
     * 
@throws Exception
     
*/
    
public void deenDemo()throws Exception{
        String str
="www.17lotto.com";
        
byte bstr[]=str.getBytes("utf-8");
        
//构成一个RSA密钥
        System.out.println("\nStart generating RSA key");
        KeyPairGenerator keyGen
=KeyPairGenerator.getInstance("RSA");
        keyGen.initialize(
1024);
        KeyPair key
=keyGen.generateKeyPair();
        
//保存公/私密钥
        File pubfile=new File("f:\\public.dat");
        File prifile
=new File("f:\\private.dat");
        OutputStream pubos
=new FileOutputStream(pubfile);
        OutputStream prios
=new FileOutputStream(prifile);
        pubos.write(key.getPublic().getEncoded());
        prios.write(key.getPrivate().getEncoded());
        pubos.flush();
        prios.flush();
        pubos.close();
        prios.close();
        
        System.out.println(
"Finish generating RSA key");        
        
//获得一个RSA的Cipher类,使用公鈅加密
        Cipher cipher=Cipher.getInstance("RSA/ECB/PKCS1Padding");
        System.out.println(
"\n"+cipher.getProvider().getInfo());

        System.out.println(
"\nStart encryption");
        cipher.init(Cipher.ENCRYPT_MODE,key.getPublic());
        
byte[] cipherText=cipher.doFinal(bstr);
        
        File pub_cryptograph
=new File("f:\\pub_cryptograph.dat");
        OutputStream os
=new FileOutputStream(pub_cryptograph);
        os.write(cipherText);
        os.flush();
        os.close();
        
        System.out.println(
"Finish encryption:");
        System.out.println(
new String(cipherText,"UTF8"));        
        
//使用私鈅解密
        System.out.println("\nStart decryption");
        cipher.init(Cipher.DECRYPT_MODE,key.getPrivate());
        
byte[] newPlainText=cipher.doFinal(cipherText);
        System.out.println(
"Finish decryption:");
        System.out.println(
new String(newPlainText,"UTF8"));
        
    }
    
/**
     * 加裁私钥,解密公钥加密的文的文件
     * 
@throws Exception
     
*/
    
public void fromfielEnDeDemo()throws Exception{
        File prifile
=new File("f:\\private.dat");
        FileInputStream fsprivateKey 
= new FileInputStream(prifile); 
        BufferedInputStream bfsprivateKey 
= new BufferedInputStream(fsprivateKey); 
        
byte[] byteprivateKey = new byte[bfsprivateKey.available()]; 
        bfsprivateKey.read(byteprivateKey); 
        bfsprivateKey.close();
        
//X509EncodedKeySpec priKeySpec = new X509EncodedKeySpec(byteprivateKey);  公钥加载法
        PKCS8EncodedKeySpec priKeySpec = new PKCS8EncodedKeySpec(byteprivateKey);  //私钥加载
        
        KeyFactory keyFactory 
= KeyFactory.getInstance("RSA"); 
        PrivateKey priKey 
= keyFactory.generatePrivate(priKeySpec); 
        System.out.println(priKey.getFormat());
        
        Cipher cipher
=Cipher.getInstance("RSA/ECB/PKCS1Padding");
        cipher.init(Cipher.DECRYPT_MODE,priKey);
        
        File pubcryptographfile
=new File("f:\\pub_cryptograph.dat");
        FileInputStream pubcis 
= new FileInputStream(pubcryptographfile);     
        
byte cstr[]=new byte[pubcis.available()];
        pubcis.read(cstr);
        pubcis.close();
        
        
byte[] newPlainText=cipher.doFinal(cstr);
        System.out.println(
"Finish decryption:");
        System.out.println(
new String(newPlainText,"UTF8"));        
    }
    
    
    
/**
     * 
@param args
     
*/
    
public static void main(String[] args) throws Exception{
        
// TODO Auto-generated method stub
        PublicExample pe=new PublicExample();
        pe.fromfielEnDeDemo();
    }

}

package demo.encrypt;

import java.security.*;

/**
 * <p>数字签名</p>
 * <pre>
 *   使用RSA私钥对信息摘要签名,然后用公钥进行解密
 * </pre>
 * 
@author peidw
 *
 
*/
public class DigitalSignature2Example {
    
    
public void test () throws Exception {
        String str
="www.17lotto.com";
        
byte[] bstr=str.getBytes("utf-8");
        
//形成RSA公私钥对
        System.out.println("\nStart generating RSA key");
        KeyPairGenerator keyGen
=KeyPairGenerator.getInstance("RSA");
        keyGen.initialize(
1024);
        KeyPair key
=keyGen.generateKeyPair();
        
        Signature sig
=Signature.getInstance("SHA1WithRSA");
        sig.initSign(key.getPrivate());
        sig.update(bstr);
        
byte[] signature=sig.sign();
        System.out.println(sig.getProvider().getInfo());
        System.out.println(
"\nSignature:");
        System.out.println(
new String(signature,"utf-8"));

        
//使用公鈅验证
        System.out.println("\nStart signature verification");
        sig.initVerify(key.getPublic());
        sig.update(bstr);
        
try{
            
if(sig.verify(signature)){
              System.out.println(
"Signature verified");
            }
else System.out.println("Signature failed");
        }
catch(SignatureException e){
            System.out.println(
"Signature failed");
        }        

        
    }
    
    
/**
     * 
@param args
     
*/
    
public static void main(String[] args) {
        
// TODO Auto-generated method stub

    }

}
posted on 2008-04-15 11:44 有猫相伴的日子 阅读(1340) 评论(0)  编辑  收藏 所属分类: jdk

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