bcrypt (1) - Linux Manuals

bcrypt: blowfish file encryption

NAME

bcrypt - blowfish file encryption

SYNOPSIS

bcrypt [-orc][-sN] file ...

DESCRIPTION

bcrypt encrypts and decrypts files using the blowfish algorithm.

Encrypted files will be saved with an extension of .bfe. Any files ending in .bfe will be assumed to be encrypted with bcrypt and will attempt to decrypt them. Any other input files will be encrypted. If more than one type of file is given, bcrypt will process all files which are the same as the first filetype given.

By default, 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.

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 blowfish algorithm. However, it is still wise to use a strong passphrase.

OPTIONS

-o

print output to standard out. Implies -r.

-c

DO NOT compress files before encryption.

-r

DO NOT remove input files after processing

-sN

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.

NOTES

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 bcrypt without any options.

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.

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.

AUTHOR

johnny shelley

<jshelley [at] cahaus.com>, <jshelley [at] ictransnet.com>

DISTRIBUTION

bcrypt includes Paul Kocher's implementation of the blowfish algorithm. The version distributed with bcrypt has been altered. Original sources are available from http://www.counterpane.com/bfsh-koc.zip