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OpenPGP加密解密文件

Posted on 2014-12-10 06:50 云自无心水自闲 阅读(10840) 评论(5)  编辑  收藏 所属分类: Java心得体会
OpenPGP 号称是世界上使用最广泛的邮件加密标准.  OpenPGP is the most widely used email encryption standard in the world. ( http://www.openpgp.org/ )
这篇例子介绍如何使用这个标准进行文件的加密解密 (https://www.bouncycastle.org/latest_releases.html, 需要下载: bcprov-jdk15on-151.jar, bcpg-jdk15on-151.jar).

主要是使用bouncycastle提供的OpenPGP的库来完成这个功能,参照了其提供的示例程序,进行了部分改动 ( Bouncy Castle 是一种用于 Java 平台的开放源码的轻量级密码术包。它支持大量的密码术算法,并提供 JCE 1.2.1 的实现。因为 Bouncy Castle 被设计成轻量级的,所以从 J2SE 1.4 到 J2ME(包括 MIDP)平台,它都可以运行。它是在 MIDP 上运行的唯一完整的密码术包。)
1. 添加循环遍历来查找第一个可用的message
2. 需要注意的是在main函数中的,如果不添加这一句的话 Security.addProvider(new BouncyCastleProvider()); 程序运行中会报错:No such Provider "BC"
3. 
错误Exception in thread "main" java.security.InvalidKeyException: Illegal key size or default parameters , 这是因为java缺省的库支持的key长度比较短,需要到oracle的网站上去下载一个支持更长key的库覆盖原有的库文件
<JAVA_HOME>/lib/securty/ 目录下的两个jar文件
local_policy.jar and US_export_policy.jar
搜索这个文件: Java Cryptography Extension (JCE) Unlimited Strength Jurisdiction Policy Files

package org.bouncycastle.openpgp.examples;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.security.NoSuchProviderException;
import java.security.SecureRandom;
import java.security.Security;
import java.util.Iterator;

import org.bouncycastle.bcpg.ArmoredOutputStream;
import org.bouncycastle.bcpg.CompressionAlgorithmTags;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
import org.bouncycastle.openpgp.PGPCompressedData;
import org.bouncycastle.openpgp.PGPEncryptedData;
import org.bouncycastle.openpgp.PGPEncryptedDataGenerator;
import org.bouncycastle.openpgp.PGPEncryptedDataList;
import org.bouncycastle.openpgp.PGPException;
import org.bouncycastle.openpgp.PGPLiteralData;
import org.bouncycastle.openpgp.PGPOnePassSignatureList;
import org.bouncycastle.openpgp.PGPPrivateKey;
import org.bouncycastle.openpgp.PGPPublicKey;
import org.bouncycastle.openpgp.PGPPublicKeyEncryptedData;
import org.bouncycastle.openpgp.PGPSecretKeyRingCollection;
import org.bouncycastle.openpgp.PGPSignatureList;
import org.bouncycastle.openpgp.PGPUtil;
import org.bouncycastle.openpgp.jcajce.JcaPGPObjectFactory;
import org.bouncycastle.openpgp.operator.jcajce.JcaKeyFingerprintCalculator;
import org.bouncycastle.openpgp.operator.jcajce.JcePGPDataEncryptorBuilder;
import org.bouncycastle.openpgp.operator.jcajce.JcePublicKeyDataDecryptorFactoryBuilder;
import org.bouncycastle.openpgp.operator.jcajce.JcePublicKeyKeyEncryptionMethodGenerator;
import org.bouncycastle.util.io.Streams;

/**
 * A simple utility class that encrypts/decrypts public key based
 * encryption files.
 * <p>
 * To encrypt a file: KeyBasedFileProcessor -e [-a|-ai] fileName publicKeyFile.<br>
 * If -a is specified the output file will be "ascii-armored".
 * If -i is specified the output file will be have integrity checking added.
 * <p>
 * To decrypt: KeyBasedFileProcessor -d fileName secretKeyFile passPhrase.
 * <p>
 * Note 1: this example will silently overwrite files, nor does it pay any attention to
 * the specification of "_CONSOLE" in the filename. It also expects that a single pass phrase
 * will have been used.
 * <p>
 * Note 2: if an empty file name has been specified in the literal data object contained in the
 * encrypted packet a file with the name filename.out will be generated in the current working directory.
 
*/
public class KeyBasedFileProcessor
{
    private static void decryptFile(
        String inputFileName,
        String keyFileName,
        char[] passwd,
        String defaultFileName)
        throws IOException, NoSuchProviderException
    {
        InputStream in = new BufferedInputStream(new FileInputStream(inputFileName));
        InputStream keyIn = new BufferedInputStream(new FileInputStream(keyFileName));
        decryptFile(in, keyIn, passwd, defaultFileName);
        keyIn.close();
        in.close();
    }

    /**
     * decrypt the passed in message stream
     
*/
    private static void decryptFile(
        InputStream in,
        InputStream keyIn,
        char[]      passwd,
        String      defaultFileName)
        throws IOException, NoSuchProviderException
    {
        in = PGPUtil.getDecoderStream(in);
        
        try
        {
            JcaPGPObjectFactory pgpF = new JcaPGPObjectFactory(in);
            PGPEncryptedDataList    enc;

            Object                  o = pgpF.nextObject();
            //
            
// the first object might be a PGP marker packet.
            
//
            if (o instanceof PGPEncryptedDataList)
            {
                enc = (PGPEncryptedDataList)o;
            }
            else
            {
                enc = (PGPEncryptedDataList)pgpF.nextObject();
            }
            
            //
            
// find the secret key
            
//
            Iterator                    it = enc.getEncryptedDataObjects();
            PGPPrivateKey               sKey = null;
            PGPPublicKeyEncryptedData   pbe = null;
            PGPSecretKeyRingCollection  pgpSec = new PGPSecretKeyRingCollection(
                PGPUtil.getDecoderStream(keyIn), new JcaKeyFingerprintCalculator());

            while (sKey == null && it.hasNext())
            {
                pbe = (PGPPublicKeyEncryptedData)it.next();
                
                sKey = PGPExampleUtil.findSecretKey(pgpSec, pbe.getKeyID(), passwd);
            }
            
            if (sKey == null)
            {
                throw new IllegalArgumentException("secret key for message not found.");
            }
    
            InputStream         clear = pbe.getDataStream(new JcePublicKeyDataDecryptorFactoryBuilder().setProvider("BC").build(sKey));
            
            JcaPGPObjectFactory    plainFact = new JcaPGPObjectFactory(clear);
            
            Object              message = plainFact.nextObject();
    
            while ( true ) {
                if (message instanceof PGPCompressedData)
                {
                    PGPCompressedData   cData = (PGPCompressedData)message;
                    JcaPGPObjectFactory    pgpFact = new JcaPGPObjectFactory(cData.getDataStream());
                    
                    message = pgpFact.nextObject();
                }
                
                if (message instanceof PGPLiteralData)
                {
                    PGPLiteralData ld = (PGPLiteralData)message;

                    String outFileName = ld.getFileName();
                    if (outFileName.length() == 0)
                    {
                        outFileName = defaultFileName;
                    }

                    InputStream unc = ld.getInputStream();
                    OutputStream fOut = new BufferedOutputStream(new FileOutputStream(outFileName));

                    Streams.pipeAll(unc, fOut);

                    fOut.close();
                    break;
                }
                else if (message instanceof PGPOnePassSignatureList)
                {
                    System.out.println("encrypted message contains a signed message - not literal data.");
                }
                else if (message instanceof PGPSignatureList)
                {
                    System.out.println("encrypted message contains a signed message - not literal data.");
                }
                else
                {
                    throw new PGPException("message is not a simple encrypted file - type unknown.");
                }
                message = plainFact.nextObject();
            }
            
            if (pbe.isIntegrityProtected())
            {
                if (!pbe.verify())
                {
                    System.err.println("message failed integrity check");
                }
                else
                {
                    System.err.println("message integrity check passed");
                }
            }
            else
            {
                System.err.println("no message integrity check");
            }
        }
        catch (PGPException e)
        {
            System.err.println(e);
            if (e.getUnderlyingException() != null)
            {
                e.getUnderlyingException().printStackTrace();
            }
        }
    }

    private static void encryptFile(
        String          outputFileName,
        String          inputFileName,
        String          encKeyFileName,
        boolean         armor,
        boolean         withIntegrityCheck)
        throws IOException, NoSuchProviderException, PGPException
    {
        OutputStream out = new BufferedOutputStream(new FileOutputStream(outputFileName));
        PGPPublicKey encKey = PGPExampleUtil.readPublicKey(encKeyFileName);
        encryptFile(out, inputFileName, encKey, armor, withIntegrityCheck);
        out.close();
    }

    private static void encryptFile(
        OutputStream    out,
        String          fileName,
        PGPPublicKey    encKey,
        boolean         armor,
        boolean         withIntegrityCheck)
        throws IOException, NoSuchProviderException
    {
        if (armor)
        {
            out = new ArmoredOutputStream(out);
        }

        try
        {
            byte[] bytes = PGPExampleUtil.compressFile(fileName, CompressionAlgorithmTags.ZIP);

            PGPEncryptedDataGenerator encGen = new PGPEncryptedDataGenerator(
                new JcePGPDataEncryptorBuilder(PGPEncryptedData.CAST5).setWithIntegrityPacket(withIntegrityCheck).setSecureRandom(new SecureRandom()).setProvider("BC"));

            encGen.addMethod(new JcePublicKeyKeyEncryptionMethodGenerator(encKey).setProvider("BC"));

            OutputStream cOut = encGen.open(out, bytes.length);

            cOut.write(bytes);
            cOut.close();

            if (armor)
            {
                out.close();
            }
        }
        catch (PGPException e)
        {
            System.err.println(e);
            if (e.getUnderlyingException() != null)
            {
                e.getUnderlyingException().printStackTrace();
            }
        }
    }

    public static void main(
        String[] args)
        throws Exception
    {
        Security.addProvider(new BouncyCastleProvider());

        if (args.length == 0)
        {
            System.err.println("usage: KeyBasedFileProcessor -e|-d [-a|ai] file [secretKeyFile passPhrase|pubKeyFile]");
            return;
        }

        if (args[0].equals("-e"))
        {
            if (args[1].equals("-a") || args[1].equals("-ai") || args[1].equals("-ia"))
            {
                encryptFile(args[2] + ".asc", args[2], args[3], true, (args[1].indexOf('i') > 0));
            }
            else if (args[1].equals("-i"))
            {
                encryptFile(args[2] + ".bpg", args[2], args[3], falsetrue);
            }
            else
            {
                encryptFile(args[1] + ".bpg", args[1], args[2], falsefalse);
            }
        }
        else if (args[0].equals("-d"))
        {
            decryptFile(args[1], args[2], args[3].toCharArray(), new File(args[1]).getName() + ".out");
        }
        else
        {
            System.err.println("usage: KeyBasedFileProcessor -d|-e [-a|ai] file [secretKeyFile passPhrase|pubKeyFile]");
        }
    }
}


asdf


评论

# re: OpenPGP加密解密文件   回复  更多评论   

2014-12-11 11:47 by 专业祛痘
不错的文章,赞一个,我还想问楼主个问题,是不是文件加密了,就一定安全了呢

# re: OpenPGP加密解密文件   回复  更多评论   

2014-12-11 19:45 by usherlight
@专业祛痘
从理论上来说,如果你的私钥和密码保存妥当,使用的密钥长度足够的话,被加密的文件是不可能被破解的. 就算要破解,需要消耗的时间也将是一个非常大的数字

# re: OpenPGP加密解密文件   回复  更多评论   

2014-12-26 16:36 by bu 李
可以提供下这个PGPExampleUtil类吗?

# re: OpenPGP加密解密文件 [未登录]  回复  更多评论   

2015-05-29 15:14 by 123
@usherlight
为什么我的程序会进这个判断里,求解,急。。。。
else if (message instanceof PGPOnePassSignatureList)
{
System.out.println("encrypted message contains a signed message - not literal data.");
}

# re: OpenPGP加密解密文件   回复  更多评论   

2016-05-20 11:06 by vigo
还是直接拿源码包中的 两个实例代码,直接运行就OK,这个类改的,解密文件跳过去了。

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