Sleuth Kit Java Bindings (JNI)  4.3
Java bindings for using The Sleuth Kit
EncodedFileUtil.java
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1 /*
2  * SleuthKit Java Bindings
3  *
4  * Copyright 2011-2016 Basis Technology Corp.
5  * Contact: carrier <at> sleuthkit <dot> org
6  *
7  * Licensed under the Apache License, Version 2.0 (the "License");
8  * you may not use this file except in compliance with the License.
9  * You may obtain a copy of the License at
10  *
11  * http://www.apache.org/licenses/LICENSE-2.0
12  *
13  * Unless required by applicable law or agreed to in writing, software
14  * distributed under the License is distributed on an "AS IS" BASIS,
15  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16  * See the License for the specific language governing permissions and
17  * limitations under the License.
18  */
19 package org.sleuthkit.datamodel;
20 
21 import java.io.IOException;
22 import java.io.RandomAccessFile;
23 import java.util.Arrays;
24 
28 class EncodedFileUtil {
29 
30  final static private int HEADER_LENGTH = 32; // All headers must be this long
31  final static private String XOR1_HEADER = "TSK_CONTAINER_XOR1_xxxxxxxxxxxxx";
32 
39  static String getHeader(TskData.EncodingType type) throws IOException{
40  switch (type){
41  case XOR1:
42  return XOR1_HEADER;
43  default:
44  throw new IOException("Can not get header for " + type.toString());
45  }
46  }
47 
57  static byte [] getEncodedHeader(TskData.EncodingType type) throws IOException{
58  if(type.equals(TskData.EncodingType.NONE)){
59  throw new IOException("Can not get encoded header for " + type.toString());
60  }
61  byte [] encHeader = new byte[HEADER_LENGTH];
62  byte [] plainHeader = getHeader(type).getBytes();
63 
64  for(int i = 0;i < HEADER_LENGTH;i++){
65  encHeader[i] = encodeByte(plainHeader[i], type);
66  }
67  return encHeader;
68  }
69 
75  static int getHeaderLength(){
76  return HEADER_LENGTH;
77  }
78 
86  static byte encodeByte(byte b, TskData.EncodingType type) throws IOException{
87  switch (type){
88  case XOR1:
89  return ((byte)(b ^ 0xca));
90  default:
91  throw new IOException("Can not encode byte with encoding type " + type.toString());
92  }
93  }
94 
102  static byte decodeByte(byte b, TskData.EncodingType type) throws IOException{
103  switch (type){
104  case XOR1:
105  return ((byte)(b ^ 0xca));
106  default:
107  throw new IOException("Can not decode byte with encoding type " + type.toString());
108  }
109  }
110 
117  static TskData.EncodingType getEncoding(RandomAccessFile fileHandle){
118  try{
119  long curOffset = fileHandle.getFilePointer();
120  if (curOffset != 0) {
121  fileHandle.seek(0);
122  }
123  byte[] header = new byte[HEADER_LENGTH];
124  int bytesRead = fileHandle.read(header, 0, HEADER_LENGTH);
125  if(bytesRead != HEADER_LENGTH){
126  return TskData.EncodingType.NONE;
127  }
128 
129  return(getTypeFromHeader(header));
130  } catch (IOException ex){
131  return TskData.EncodingType.NONE;
132  }
133  }
134 
140  static private TskData.EncodingType getTypeFromHeader(byte[] header){
141  if(header.length != HEADER_LENGTH){
142  return TskData.EncodingType.NONE;
143  }
144 
145  if(Arrays.equals(header, XOR1_HEADER.getBytes())){
146  return TskData.EncodingType.XOR1;
147  } else {
148  return TskData.EncodingType.NONE;
149  }
150 
151  }
152 }

Copyright © 2011-2015 Brian Carrier. (carrier -at- sleuthkit -dot- org)
This work is licensed under a Creative Commons Attribution-Share Alike 3.0 United States License.