MAN page from openSUSE Leap 42 apg-2.2.3-4.1.x86_64.rpm
Section: User Manual (1)
Updated: 2003 Jun 19Index
apgbfm- APG Bloom filter management program
SYNOPSISapgbfm-f filter -n numofwords
]apgbfm-f filter -d dictfile
]apgbfm-f filter -a word
]apgbfm-f filter -A dictfile
]apgbfm-f filter -c word
]apgbfm-f filter -C dictfile
is used to manage Bloom filter that is used to restrict password generationin APG
pasword generation software. Usage of the Bloom filter allows to speedup password check for large dictionaries and has some other benefits.
The idea to use Bloom filter for that purpose is came from the description ofthe OPUS project OPUS: Preventing Weak Password ChoicesPurdue 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 passwordchecking systems.
In simple words, apgbfm generates n hash values for every word andsets corresponding bits in filter file to 1. To check the word apgbfmgenerates the same hash functions for that word and if all n correspondingbits 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, orapgd.
- WARNING !!!
- Filter file format can be changedin 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.
- -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 youwant to fill filter dynamicaly.
- -d dictfile
- create new filter from dictfile. It may take a lot of time togenerate filter from a big dictionary. In that dictionary you may placewords (one per line) that should not appear as generated passwords.For example: user names common words, etc. You even can use one of thedictionaries 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 100words 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 workingapgbfm 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.
- quiet mode.
- create new filter in case-insensitive mode.
- print version information.
- print help information.
On successful completion of its task,apgbfm
will complete with exit code 0. An exit code of -1 indicates an erroroccurred. Textual errors are written to the standard error stream.
If you've found one, please send bug description to the author.
This man page is Alpha too.
Adel I. Mirzazhanov, <a-delAATTiname.com>
Project home page: http://www.adel.nursat.kz/apg/
- EXIT CODE
- SEE ALSO
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