NAME

       krb5-strength-wordlist - Create a krb5-strength database from a word list

SYNOPSIS

       krb5-strength-wordlist [-am] [-c output-cdb] [-l min-length]
           [-L max-length] [-o output-wordlist] [-s output-sqlite]
           [-x exclude ...] wordlist

DESCRIPTION

       krb5-strength-wordlist converts a word list (a file containing one word per line) into a
       database that can be used by the krb5-strength plugin or heimdal-strength command for
       checking passwords.  Two database formats are supported, with different features.  CDB is
       more space-efficient and possibly faster, but supports checking passwords only against
       exact matches or simple transformations (removing small numbers of leading and trailing
       characters).  SQLite creates a much larger database, but supports rejecting any password
       within edit distance one of a word in the word list.

       CDB is a format invented by Dan Bernstein for fast, constant databases.  The database is
       fixed during creation and cannot be changed without rebuilding it, and is optimized for
       very fast access.  For cdb, the database generated by this program will have keys for each
       word in the word list and the constant 1 as the value.

       SQLite stores the word list in a single table containing both each word and each word
       reversed.  This allows the krb5-strength plugin or heimdal-strength command to reject
       passwords within edit distance one of any word in the word list.  (Edit distance one means
       that the word list entry can be formed by changing a single character of the password,
       either by adding one character, removing one character, or changing one character to a
       different character.)  However, the SQLite database will be much larger and lookups may be
       somewhat slower.

       krb5-strength-wordlist takes one argument, the input word list file.  Use the -c option to
       specify an output CDB file, -s to specify an output SQLite file, or -o to just filter the
       word list against the criteria given on the command line and generate a new word list.
       The input word list file does not have to be sorted.  See the individual option
       descriptions for more information.

OPTIONS

       -a, --ascii
           Filter all words that contain non-ASCII characters or control characters from the
           resulting cdb file, leaving only words that consist solely of ASCII non-control
           characters.

       -c output-cdb, --cdb=output-cdb
           Create a CDB database in output-cdb.  A temporary file named after output-cdb with
           ".data" appended will be created in the same directory and used to stage the database
           contents.  The actual CDB file will be built using the cdb command, which must be on
           the user's path.  If either file already exists, krb5-strength-wordlist will abort
           with an error.

           This option cannot be used with -o or -s.

       -L maximum, --max-length=maximum
           Filter all words of length greater than maximum from the resulting cdb database.  The
           length of each line (minus the separating newline) in the input word list will be
           checked against minimum and will be filtered out of the resulting database if it is
           shorter.  Useful for generating password dictionaries from word lists that contain
           random noise that's highly unlikely to be used as a password.

           The default is to not filter out any words for maximum length.

       -l minimum, --min-length=minimum
           Filter all words of length less than minimum from the resulting cdb database.  The
           length of each line (minus the separating newline) in the input word list will be
           checked against minimum and will be filtered out of the resulting database if it is
           shorter.  Useful for generating password dictionaries where shorter passwords will be
           rejected by a generic length check and no dictionary lookup will be done for a
           transform of the password shorter than the specified minimum.

           The default is not to filter out any words for minimum length.

       -m, --man, --manual
           Print out this documentation (which is done simply by feeding the script to "perldoc
           -t").

       -o wordlist, --output=wordlist
           Rather than creating a database, apply the filter rules given by the other command-
           line arguments and generate a new word list in the file name given by the wordlist
           option.  This can be used to reduce the size of a raw word list file (such as one
           taken from Internet sources) by removing the words that will be filtered out of the
           dictionary anyway, thus reducing the size of the source required to regenerate the
           dictionary.

           This option cannot be used with -c or -s.

       -s output-sqlite, --sqlite=output-sqlite
           Create a SQLite database in output-sqlite.  If this file already exists,
           krb5-strength-wordlist will abort with an error.  The resulting SQLite database will
           have one table, "passwords", with two columns, "password" and "drowssap".  The first
           holds a word from the word list, and the second holds the same word reversed.

           Using this option requires the DBI and DBD::SQLite Perl modules be installed.

           This option cannot be used with -c or -o.

       -x exclude, --exclude=exclude
           Filter all words matching the regular expression exclude from the resulting cdb
           database.  This regular expression will be matched against each line of the source
           word list after the trailing newline is removed.  This option may be given repeatedly
           to add multiple exclusion regexes.

AUTHOR

       Russ Allbery <eagle@eyrie.org>

COPYRIGHT AND LICENSE

       Copyright 2016, 2020 Russ Allbery <eagle@eyrie.org>

       Copyright 2013-2014 The Board of Trustees of the Leland Stanford Junior University

       Permission is hereby granted, free of charge, to any person obtaining a copy of this
       software and associated documentation files (the "Software"), to deal in the Software
       without restriction, including without limitation the rights to use, copy, modify, merge,
       publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
       to whom the Software is furnished to do so, subject to the following conditions:

       The above copyright notice and this permission notice shall be included in all copies or
       substantial portions of the Software.

       THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
       INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
       PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
       FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
       OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
       DEALINGS IN THE SOFTWARE.

       SPDX-License-Identifier: MIT

SEE ALSO

       cdb(1), DBI, DBD::SQLite

       The cdb file format is defined at <http://cr.yp.to/cdb.html>.

       The current version of this program is available from its web page at
       <https://www.eyrie.org/~eagle/software/krb5-strength/> as part of the krb5-strength
       package.