/* ==================================================================== | |
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. | |
==================================================================== */ | |
package org.apache.poi.poifs.crypt.standard; | |
import java.io.IOException; | |
import org.apache.poi.EncryptedDocumentException; | |
import org.apache.poi.poifs.crypt.ChainingMode; | |
import org.apache.poi.poifs.crypt.CipherAlgorithm; | |
import org.apache.poi.poifs.crypt.EncryptionInfo; | |
import org.apache.poi.poifs.crypt.EncryptionInfoBuilder; | |
import org.apache.poi.poifs.crypt.HashAlgorithm; | |
import org.apache.poi.util.LittleEndianInput; | |
public class StandardEncryptionInfoBuilder implements EncryptionInfoBuilder { | |
/** | |
* initialize the builder from a stream | |
*/ | |
@Override | |
public void initialize(EncryptionInfo info, LittleEndianInput dis) throws IOException { | |
/* int hSize = */ dis.readInt(); | |
StandardEncryptionHeader header = new StandardEncryptionHeader(dis); | |
info.setHeader(header); | |
info.setVerifier(new StandardEncryptionVerifier(dis, header)); | |
if (info.getVersionMinor() == 2 && (info.getVersionMajor() == 3 || info.getVersionMajor() == 4)) { | |
StandardDecryptor dec = new StandardDecryptor(); | |
dec.setEncryptionInfo(info); | |
info.setDecryptor(dec); | |
} | |
} | |
/** | |
* initialize the builder from scratch | |
*/ | |
@Override | |
public void initialize(EncryptionInfo info, CipherAlgorithm cipherAlgorithm, HashAlgorithm hashAlgorithm, int keyBits, int blockSize, ChainingMode chainingMode) { | |
if (cipherAlgorithm == null) { | |
cipherAlgorithm = CipherAlgorithm.aes128; | |
} | |
if (cipherAlgorithm != CipherAlgorithm.aes128 && | |
cipherAlgorithm != CipherAlgorithm.aes192 && | |
cipherAlgorithm != CipherAlgorithm.aes256) { | |
throw new EncryptedDocumentException("Standard encryption only supports AES128/192/256."); | |
} | |
if (hashAlgorithm == null) { | |
hashAlgorithm = HashAlgorithm.sha1; | |
} | |
if (hashAlgorithm != HashAlgorithm.sha1) { | |
throw new EncryptedDocumentException("Standard encryption only supports SHA-1."); | |
} | |
if (chainingMode == null) { | |
chainingMode = ChainingMode.ecb; | |
} | |
if (chainingMode != ChainingMode.ecb) { | |
throw new EncryptedDocumentException("Standard encryption only supports ECB chaining."); | |
} | |
if (keyBits == -1) { | |
keyBits = cipherAlgorithm.defaultKeySize; | |
} | |
if (blockSize == -1) { | |
blockSize = cipherAlgorithm.blockSize; | |
} | |
boolean found = false; | |
for (int ks : cipherAlgorithm.allowedKeySize) { | |
found |= (ks == keyBits); | |
} | |
if (!found) { | |
throw new EncryptedDocumentException("KeySize "+keyBits+" not allowed for Cipher "+cipherAlgorithm.toString()); | |
} | |
info.setHeader(new StandardEncryptionHeader(cipherAlgorithm, hashAlgorithm, keyBits, blockSize, chainingMode)); | |
info.setVerifier(new StandardEncryptionVerifier(cipherAlgorithm, hashAlgorithm, keyBits, blockSize, chainingMode)); | |
StandardDecryptor dec = new StandardDecryptor(); | |
dec.setEncryptionInfo(info); | |
info.setDecryptor(dec); | |
StandardEncryptor enc = new StandardEncryptor(); | |
enc.setEncryptionInfo(info); | |
info.setEncryptor(enc); | |
} | |
} |