apgbfm - Online in the Cloud

This is the command apgbfm that can be run in the OnWorks free hosting provider using one of our multiple free online workstations such as Ubuntu Online, Fedora Online, Windows online emulator or MAC OS online emulator

PROGRAM:

NAME


apgbfm - APG Bloom filter management program

SYNOPSIS


apgbfm -f filter -n numofwords [-q] [-s]
apgbfm -f filter -d dictfile [-q] [-s]
apgbfm -f filter -a word [-q]
apgbfm -f filter -A dictfile [-q]
apgbfm -f filter -c word [-q]
apgbfm -f filter -C dictfile [-q]
apgbfm -i filter
apgbfm [-v] [-h]

DESCRIPTION


apgbfm is used to manage Bloom filter that is used to restrict password generation in APG
pasword generation software. Usage of the Bloom filter allows to speed up password check
for large dictionaries and has some other benefits.

The idea to use Bloom filter for that purpose is came from the description of the OPUS
project OPUS: Preventing Weak Password Choices Purdue Technical Report CSD-TR 92-028
writen by Eugene H. Spafford.

You can obtain this article from:
http://www.cerias.purdue.edu/homes/spaf/tech-reps/9128.ps
It has very nice description of Bloom filter and it's advantages for password checking
systems.

In simple words, apgbfm generates n hash values for every word and sets corresponding bits
in filter file to 1. To check the word apgbfm generates the same hash functions for that
word and if all n corresponding bits in filter file are set to 1 then it suppose that word
exists in dicionary. apgbfm uses SHA-1 as a hash function.

apgbfm can be used as standalone utility, not only with apg, or apgd.

WARNING !!!
Filter file format can be changed in the future. I'll try to make file formats
compatible but i can not guaranty this.

WARNING !!!
apgbfm may slow down your computer during filter creation.

OPTIONS


-f filter
use filter as the name for Bloom filter filename.

-i filter
print information about filter.

-n numofwords
create new empty filter for numofwords number of words. Useful when you want to
fill filter dynamicaly.

-d dictfile
create new filter from dictfile. It may take a lot of time to generate filter from
a big dictionary. In that dictionary you may place words (one per line) that should
not appear as generated passwords. For example: user names common words, etc. You
even can use one of the dictionaries that come with dictionary password crackers.
This check is case sensitive. For example, if you want to reject word 'root', you
should insert in dictfile words: root, Root, RoOt, ... , ROOT. To indicate that
program is working apgbfm prints dot for every 100 words added in dictionary.

-a word
add word to the filter.

-A dictfile
add all words from dictfile to the filter. To indicate that program is working
apgbfm prints dot for every 100 words added in dictionary.

-c word
check word for appearance in the filter.

-C dictfile
check every word from dictfile for appearance in the filter.

-q quiet mode.

-s create new filter in case-insensitive mode.

-v print version information.

-h print help information.

EXIT CODE


On successful completion of its task, apgbfm will complete with exit code 0. An exit code
of -1 indicates an error occurred. Textual errors are written to the standard error
stream.

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