APG Bloom filter management program
-f filter -n numofwords [-q]
apgbfm -f filter -d dictfile
apgbfm -f filter -a word [-q]
apgbfm -f filter -A dictfile
apgbfm -f filter -c word [-q]
apgbfm -f filter -C dictfile
apgbfm -i filter
apgbfm [-v] [-h]
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
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:
It has very nice description of Bloom filter and it’s
advantages for password checking systems.
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
can be used as standalone utility, not only with apg,
Filter file format can be
changed in the future. I’ll try to make file formats
compatible but i can not guaranty this.
apgbfm may slow down
your computer during filter creation.
use filter as the name
for Bloom filter filename.
print information about
create new empty filter for
numofwords number of words. Useful when you want to
fill filter dynamicaly.
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.
add word to the
add all words from
dictfile to the filter. To indicate that program is
working apgbfm prints dot for every 100 words added
check word for
appearance in the filter.
check every word from
dictfile for appearance in the filter.
create new filter in case-insensitive mode.
print version information.
print help information.
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.
you’ve found one, please send bug description to the
This man page
is Alpha too.
Project home page: http://www.adel.nursat.kz/apg/