OpenPGP加密解密文件

转载

我爱学习项目管理 2018-08-23 15:51:56 博主文章分类：技术学习

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。)

添加循环遍历来查找第一个可用的message
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"
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 下载页面(以JDK6为例)：http://www.oracle.com/technetwork/java/javase/downloads/jce-6-download-429243.html

package com.test.test;

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.
To encrypt a file: KeyBasedFileProcessor -e [-a|-ai] fileName publicKeyFile.
If -a is specified the output file will be "ascii-armored".
If -i is specified the output file will be have integrity checking added.
To decrypt: KeyBasedFileProcessor -d fileName secretKeyFile passPhrase.
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.
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], false, true);
     }
     else
     {
         encryptFile(args[1] + ".bpg", args[1], args[2], false, false);
     }
 }
 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]");
 }

} }