README
1ABOUT
2--
3Bcrypt is a cross platform file encryption utility. Encrypted files are
4portable across all supported operating systems and processors. Passphrases
5are between 8 and 56 characters and are hashed internally to a 448 bit
6key. However, all characters supplied are significant. The stronger your
7passphrase, the more secure your data.
8
9Bcrypt uses the blowfish encryption algorithm published by Bruce Schneier
10in 1993. More information on the algorithm can be found at:
11 http://www.counterpane.com/blowfish.html
12
13Specifically, bcrypt uses Paul Kocher's implementation of the algorithm.
14The source distributed with bcrypt has been slightly altered from the
15original. Original source code can be obtained from:
16 http://www.counterpane.com/bfsh-koc.zip
17
18SUPPORTED PLATFORMS
19--
20Bcrypt has been successfully tested on the following platforms:
21
22 x86
23 FreeBSD, OpenBSD, Linux, Cygwin, Win32
24 Sparc R220
25 Solaris 2.7, 2.8
26 Sparc Ultra60
27 Linux 2.4
28 Alpha
29 Linux 2.4
30 PPC G4
31 MacOS X 10.1 SERVER
32 PPC RS/6000
33 Linux 2.4
34
35No other operating systems have been tested, but most should work with
36minimal modifications. If you get bcrypt to compile without errors on any
37other platform / architecture, I'd like to know about it. If patches are
38necessary to get bcrypt work on your OS, I will try to incorporate them
39into the main distribution.
40
41If you have a machine not listed above that is incapable of compiling
42bcrypt and are willing to give me access to the machine, I will make an
43attempt to port it to your OS.
44
45SYSTEM REQUIREMENTS
46--
47zlib - http://www.gzip.org/zlib/
48
49INSTALLATION
50--
51If you're so inclined, edit config.h and change the defaults to whatever
52you think is appropriate for your needs. If you choose not to have
53bcrypt remove input files after processing, or set SECUREDELETE to 0,
54you are likely to have data on your hard drive that can be recovered
55even after deletion.
56
57All of these options can be set on the command line as well. When you're
58satisfied with the default settings, simply type:
59 make
60then su and type:
61 make install
62
63It would be wise to test the installation on a few unimportant files
64before encrypting anything you value and removing the only copy.
65
66USAGE
67--
68 bcrypt [-orc][-sN] file ...
69
70Encrypted files will be saved with an extension of .bfe. Any files ending
71in .bfe will be assumed to be encrypted with bcrypt and will attempt to
72decrypt them. Any other input files will be encrypted. If more than one
73type of file is given, bcrypt will process all files which are the same as
74the first filetype given.
75
76By default, bcrypt will compress input files before encryption, remove
77input files after they are processed (assuming they are processed
78successfully) and overwrite input files with random data to prevent data
79recovery.
80
81Passphrases may be between 8 and 56 characters. Regardless of the
82passphrase size, the key is hashed internally to 448 bits - the largest
83keysize supported by the blowfish algorithm. However, it is still wise to
84use a strong passphrase.
85
86OPTIONS
87 -o print output to standard out. Implies -r.
88
89 -c DO NOT compress files before encryption.
90
91 -r DO NOT remove input files after processing
92
93 -sN How many times to overwrite input files with random
94 data before processing. The default number of
95 overwrites is 3. Use -s0 to disable this feature.
96 No effect if -r is supplied.
97
98The options o,c and r each have the opposite effects if the appropriate
99settings are altered from the default in config.h. To determine what
100effect each of these have, run bcrypt without any options.
101
102Encrypted files should be compatible between most systems. Binary
103compatibility has been tested for all systems listed above.
104
105/* ====================================================================
106 * Copyright (c) 2002 Johnny Shelley. All rights reserved.
107 *
108 * Bcrypt is licensed under the BSD software license. See the file
109 * called 'LICENSE' that you should have received with this software
110 * for details
111 * ====================================================================
112 */
113