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
       password generation software. Usage of the Bloom filter allows one 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
       written 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.

FILES

       None.

BUGS

       None.  If you've found one, please send bug description to the author.

       This man page is Alpha too.

SEE ALSO

       apg(1)

AUTHOR

       Adel I. Mirzazhanov, <a-del@iname.com>
       Project home page: http://www.adel.nursat.kz/apg/