org.apache.poi.poifs.crypt.EcmaDecryptor Maven / Gradle / Ivy
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Licensed to the Apache Software Foundation (ASF) under one or more
contributor license agreements. See the NOTICE file distributed with
this work for additional information regarding copyright ownership.
The ASF licenses this file to You under the Apache License, Version 2.0
(the "License"); you may not use this file except in compliance with
the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
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package org.apache.poi.poifs.crypt;
import java.io.IOException;
import java.io.InputStream;
import java.security.GeneralSecurityException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Arrays;
import javax.crypto.Cipher;
import javax.crypto.CipherInputStream;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
import org.apache.poi.poifs.filesystem.DirectoryNode;
import org.apache.poi.poifs.filesystem.DocumentInputStream;
import org.apache.poi.util.LittleEndian;
/**
* @author Maxim Valyanskiy
* @author Gary King
*/
public class EcmaDecryptor extends Decryptor {
private final EncryptionInfo info;
private byte[] passwordHash;
private long _length = -1;
public EcmaDecryptor(EncryptionInfo info) {
this.info = info;
}
private byte[] generateKey(int block) throws NoSuchAlgorithmException {
MessageDigest sha1 = MessageDigest.getInstance("SHA-1");
sha1.update(passwordHash);
byte[] blockValue = new byte[4];
LittleEndian.putInt(blockValue, 0, block);
byte[] finalHash = sha1.digest(blockValue);
int requiredKeyLength = info.getHeader().getKeySize()/8;
byte[] buff = new byte[64];
Arrays.fill(buff, (byte) 0x36);
for (int i=0; i source.length) {
for(int i=source.length; i