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apg - generates several random passwords
apg [-a algorithm] [-M mode] [-E char_string] [-n num_of_pass] [-m min_pass_len] [-x max_pass_len] [-r dictfile] [-b filter_file] [-p min_substr_len] [-s] [-c cl_seed] [-d] [-y] [-l] [-t] [-q] [-h] [-v]
apg generates several random passwords. It uses several password generation algorithms (currently two) and a built-in pseudo random number generator.
Default algorithm is pronounceable password generation algorithm designed by Morrie Gasser and described in A Random Word Generator For Pronounceable Passwords National Technical Information Service (NTIS) AD-A-017676. The original paper is very old and had never been put online, so I have to use NIST implementation described in FIPS-181.
Another algorithm is simple random character generation algorithm, but it uses four user-defined symbol sets to produce random password. It means that user can choose type of symbols that should appear in password. Symbol sets are: numeric symbol set (0,...,9), capital letters symbol set (A,...,Z), small letters symbol set (a,...,z) and special symbols symbol set (#,@,!,...).
Built-in pseudo random number generator is an implementation of algorithm described in Appendix C of ANSI X9.17 or RFC 1750 with exception that it uses CAST or SHA-1 instead of Triple DES. It uses local time with precision of microseconds (see gettimeofday(2)) and /dev/random (if available) to produce initial random seed.
apg also have the ability to check generated password quality using dictionary. You can use this ability if you specify command-line options -r dictfile or -b filtername where dictfile is the dictionary file name and filtername is the name of Bloom filter file. 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. Bloom filter file should be created with apgbfm(1) utility included in apg distribution. In future releases I plan to implement some other techniques to check passwords (like pattern check) just to make life easier.
Note:
Usage of L, M, S, C will slow down password generation process.
Examples:
-M sncl
-M SNCL
-M Cn
Examples:
Command apg -a 1 -M n -n 3 -m 8 -E 23456789 will generate a
set of passwords that will look like this:
10100110
01111000
11011101
Command apg -a 1 -M nc -n 3 -m 26 -E GHIJKLMNOPQRSTUVWXYZ
will generate a set of passwords that will look like this:
16A1653CD4DE5E7BD9584A3476
C8F78E06944AFD57FB9CB882BC
8C8DF37CD792D36D056BBD5002
apg -a 0 -M sncl -n 6 -x 10 -m 8 (new style)
If you want to generate really secure passwords, you should use
option -s. To simplify apg usage, you can write a small shell
script. For example:
[begin]----> pwgen.sh
#!/bin/sh
/usr/local/bin/apg -m 8 -x 12 -s
[ end ]----> pwgen.sh
On successful completion of its task, apg will complete with exit code 0. An exit code of -1 indicates an error occurred. Textual errors are written to the standard error stream.
If /dev/random is not available, apg will display a message about it.
None.
apg is no longer maintained upstream. Alternatives include pwgen, diceware and xkcdpass.
In particular, pronouncable passwords may be prone to various
attacks and enforcing the use of certain symbolsets (via the S,
N, C and L modes of the -M option) might
even simplify attacking the password.
See Debian bug #987952.
None. If you've found one, please send bug description to the author.
apgbfm(1)
Adel I. Mirzazhanov, <a-del@iname.com>
Project home page: http://www.adel.nursat.kz/apg/
2003 Aug 04 | Automated Password Generator |