apg
generates several random passwords
see also :
apgbfm
Synopsis
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]
add an example, a script, a trick and tips
examples
source
clear
apg -m8 -t -n10 -M NCL
description
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
RFC1750 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.
options
Password
generation modes options
-a algorithm
use algorithm for
password generation.
0 - (default) pronounceable password generation
1 - random character password generation
-n num_of_pass
generate num_of_pass
number of passwords. Default is 6.
-m min_pass_len
generate password with minimum
length min_pass_len. If min_pass_len >
max_pass_len then max_pass_len = min_pass_len.
Default minimum password length is 8.
-x max_pass_len
generate password with maximum
length max_pass_len. If min_pass_len >
max_pass_len then max_pass_len = min_pass_len.
Default maximum password length is 10.
-M mode
Use symbolsets specified with
mode for password generation. mode is a text
string consisting of characters S, s,
N, n, C, c, L, l.
Where:
S
generator must use special symbol set for every
generated password.
s
generator should use special symbol set for
password generation.
N
generator must use numeral symbol set for every
generated password.
n
generator should use numeral symbol set for
password generation.
C
generator must use capital symbol set for every
generated password.
c
generator should use capital symbol set for
password generation.
L
generator must use small letters symbol set for
every generated password (always present if pronounceable
password generation algorithm is used).
l
generator should use small letters symbol set for
password generation.
R,r
not supported any more. Use -E char_string option
instead.
mode can not be more
than 4 characters in length.
Note:
Usage of L, M, N, C will slow down password generation
process.
Examples:
-M sncl or -M SNCL or -M Cn
-E char_string
exclude characters in
char_string from password generation process (in
pronounceable password generation mode you can not exclude
small letters). To include special symbols that can be
recognized by shell (apostrophe, quotes, dollar sign, etc.)
in char_string use the backslashed versions.
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
Password
quality control options
-r dictfile
check generated passwords for
their appearance in dictfile
-b
filter_file
check generated passwords for
their appearance in filter_file. filter_file
should be created with apgbfm(1) utility.
-p min_substr_len
this option tells apg(1)
to check every substring of the generated password for
appearance in filter_file. If any of such substrings
would be found in the filter_file then generated
password would be rejected and apg(1) will generate another
one. min_substr_len specifies minimum substring
length to check. This option is active only if -b
option is defined.
Pseudo
random number generator options
-s
ask user for random sequence for password generation
-c cl_seed
use cl_seed as a random
seed for password generation. I use it when i have to
generate passwords in a shell script.
Password
output options
-d
do NOT use any delimiters between generated passwords. I
use it when i have to generate passwords in a shell
script.
-y
print generated passwords and crypted passwords (see man
crypt(3))
-q
quiet mode (do not print warnings)
-l
spell genetated passwords. Useful when you want to read
generated password by telephone.
WARNING: Think twice
before read your password by phone.
-t
print pronunciation for
generated pronounceable password
-h
print help information and exit
-v
print version information and exit
default options
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
diagnostics
If /dev/random is not available, apg will display a
message about it.
exit code
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.
files
None.
bugs
None. If
you’ve found one, please send bug description to the
author.
see also
apgbfm
author
Adel I.
Mirzazhanov, <a-del[:at:]iname[:dot:]com>
Project home page: http://www.adel.nursat.kz/apg/