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The Bouncy Castle Crypto package is a Java implementation of cryptographic algorithms. This jar contains JCE provider and lightweight API for the Bouncy Castle Cryptography APIs for JDK 1.5 to JDK 1.8.

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package org.bouncycastle.crypto.util;

import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.io.OutputStream;
import java.io.Serializable;
import java.security.SecureRandom;

import org.bouncycastle.asn1.ASN1EncodableVector;
import org.bouncycastle.asn1.ASN1OctetString;
import org.bouncycastle.asn1.ASN1Sequence;
import org.bouncycastle.asn1.DEROctetString;
import org.bouncycastle.asn1.DERSequence;
import org.bouncycastle.asn1.x509.AlgorithmIdentifier;
import org.bouncycastle.crypto.CryptoServicesRegistrar;
import org.bouncycastle.util.Encodable;
import org.bouncycastle.util.io.Streams;

/**
 * JournaledAlgorithm keeps state of the JournalingSecureRandom and the
 * AlgorithmIdentifier necessary to fully resume an encryption session. This
 * class can be used to retrieve a session even if a process is completely
 * stopped. NOTE: This should be used with a shutdown hook to save the state of
 * the journaling and the algorithm identifier even in the case of a forced
 * shutdown.
 * 

* The raw encoding is in ASN.1 format. *

*

* Details: Use serialization of critical parameters of the the * JournalingSecureRandom and AlgorithmIdentifier. Because these two classes are * not serializable, create interior class to serialize only the critical * parameters in the form of byte[] arrays */ public class JournaledAlgorithm implements Encodable, Serializable { private transient JournalingSecureRandom journaling; private transient AlgorithmIdentifier algID; public JournaledAlgorithm(AlgorithmIdentifier aid, JournalingSecureRandom journaling) { if (aid == null) { throw new NullPointerException("AlgorithmIdentifier passed to JournaledAlgorithm is null"); } else if (journaling == null) { throw new NullPointerException("JournalingSecureRandom passed to JournaledAlgorithm is null"); } this.journaling = journaling; this.algID = aid; } /** * Construct from a previous encoding, using CryptoServicesRegistrar.getSecureRandom() as the backup source of entropy. * * @param encoding raw encoding of a previous JournaledAlgorithm. */ public JournaledAlgorithm(byte[] encoding) { this(encoding, CryptoServicesRegistrar.getSecureRandom()); } /** * Construct from a previous encoding, using the passed in random as a source for when the existing entropy runs out. * * @param encoding raw encoding of a previous JournaledAlgorithm. * @param random back up source of entropy. */ public JournaledAlgorithm(byte[] encoding, SecureRandom random) { if (encoding == null) { throw new NullPointerException("encoding passed to JournaledAlgorithm is null"); } else if (random == null) { throw new NullPointerException("random passed to JournaledAlgorithm is null"); } initFromEncoding(encoding, random); } private void initFromEncoding(byte[] encoding, SecureRandom random) { ASN1Sequence seq = ASN1Sequence.getInstance(encoding); this.algID = AlgorithmIdentifier.getInstance(seq.getObjectAt(0)); this.journaling = new JournalingSecureRandom(ASN1OctetString.getInstance(seq.getObjectAt(1)).getOctets(), random); } public JournalingSecureRandom getJournalingSecureRandom() { return journaling; } public AlgorithmIdentifier getAlgorithmIdentifier() { return algID; } /** * Store state of JournalingSecureRandom and AlgorithmIdentifier in temporary * file * * @param tempfile * @throws IOException */ public void storeState(File tempfile) throws IOException { if (tempfile == null) { throw new NullPointerException("file for storage is null in JournaledAlgorithm"); } // Extract key information in byte[] form FileOutputStream fOut = new FileOutputStream(tempfile); try { storeState(fOut); } finally { fOut.close(); } } public void storeState(OutputStream out) throws IOException { if (out == null) { throw new NullPointerException("output stream for storage is null in JournaledAlgorithm"); } out.write(this.getEncoded()); } public static JournaledAlgorithm getState(InputStream stateIn, SecureRandom random) throws IOException, ClassNotFoundException { if (stateIn == null) { throw new NullPointerException("stream for loading is null in JournaledAlgorithm"); } InputStream fIn = new BufferedInputStream(stateIn); try { return new JournaledAlgorithm(Streams.readAll(fIn), random); } finally { fIn.close(); } } /** * Reconstructs JournaledAlgorithm session from file containing it's raw encoding. * * @param tempfile temporary file containing serialized state * @return * @throws IOException * @throws ClassNotFoundException */ public static JournaledAlgorithm getState(File tempfile, SecureRandom random) throws IOException, ClassNotFoundException { if (tempfile == null) { throw new NullPointerException("File for loading is null in JournaledAlgorithm"); } InputStream fIn = new BufferedInputStream(new FileInputStream(tempfile)); try { return new JournaledAlgorithm(Streams.readAll(fIn), random); } finally { fIn.close(); } } public byte[] getEncoded() throws IOException { ASN1EncodableVector v = new ASN1EncodableVector(); v.add(algID); v.add(new DEROctetString(journaling.getFullTranscript())); return new DERSequence(v).getEncoded(); } private void readObject( ObjectInputStream in) throws IOException, ClassNotFoundException { in.defaultReadObject(); initFromEncoding((byte[])in.readObject(), CryptoServicesRegistrar.getSecureRandom()); } private void writeObject( ObjectOutputStream out) throws IOException { out.defaultWriteObject(); out.writeObject(getEncoded()); } }





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