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.

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/