.TH bcrypt 1 "10 September 2002" "version 1.1"
.SH NAME
bcrypt - blowfish file encryption
.SH SYNOPSIS
.BR bcrypt " ["-orc] "["-s "N]
.I file ...
.SH DESCRIPTION
.B bcrypt
encrypts and decrypts files using the
.I blowfish 
algorithm.
.PP
Encrypted files will be saved with an extension of
.BR .bfe ".
Any files ending in
.B .bfe
will be assumed to be encrypted with
.BR bcrypt " and 
will attempt to decrypt them. Any other input files will be encrypted.
If more than one type of file is given,
.B bcrypt
will process all files which are the same as the first filetype given.
.PP
By default,
.B bcrypt
will compress input files before encryption, remove input files after
they are processed (assuming they are processed successfully) and
overwrite input files with random data to prevent data recovery.
.PP
Passphrases may be between 8 and 56 characters. Regardless of the
passphrase size, the key is hashed internally to 448 bits - the
largest keysize supported by the
.IR blowfish " algorithm. However, it is still wise to use a strong
passphrase. 
.SH OPTIONS
.TP
.B -o
print output to standard out. Implies -r.
.TP
.B -c
DO NOT compress files before encryption.
.TP
.B -r
DO NOT remove input files after processing
.TP
.BI -s "N
How many times to overwrite input files with random data before deleting. 
The default number of overwrites is 3. Use -s0 to disable this 
feature. No effect if -r is supplied.
.SH NOTES
.BR ""The " -o ", "-r "  ,and " -c " options 
each have the opposite effects
if the appropriate settings are altered from the defaults in config.h. To
determine what effect each of these have on your system, run
.B bcrypt
without any options.
.PP
Encrypted files should be compatible between most systems.
Binary compatibility has been tested on all supported systems. There
is a list of supported systems in the README file that was included
with this software.
.SH BUGS
Probably.
If you find that it will not compile and run on your system, or that 
encrypted files are not compatible with other platforms, its probably 
because I don't have access to the platform in question. Patches or 
access to an unsupported machine are welcome.
.SH AUTHOR
.TP
johnny shelley 
<jshelley@cahaus.com>, 
<jshelley@ictransnet.com>
.SH DISTRIBUTION
.B bcrypt
includes Paul Kocher's implementation of the
.IR blowfish " algorithm. The version distributed with
.BR bcrypt " has been altered. Original sources are available from
http://www.counterpane.com/bfsh-koc.zip