| /* ==================================================================== |
| 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); |
| } |
| 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); |
| } |
| } |