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hfranco
Asked: 2011-04-19 14:42:14 +0800 CST

Creating random password

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I need to create passwords on the fly from a script.

Unfortunately I cannot use applications that utilize /dev/urandom because of the time it takes to create the password.

Are there other applications that I can use to create passwords on the fly?

bash password

7 Answers

  1. Best Answer

    Apparently this answer worked:

    cat /dev/urandom | tr -dc 'a-zA-Z0-9-_!@#$%^&*()_+{}|:<>?=' | fold -w 12 | head -n 4

    ... takes about .01 seconds.

    • 6

  2. The apg tool is kinda dated but still good for password generation. It supports sizing the passwords, password checking with dictionaries, generation of pronounceable or random passwords, has a built-in PRNG and /dev/random support and can generate various passwords on a bunch or on a shell script.

    Examples:

    # apg -c random_seed 
dordififId
riHegyipju
Noafrathvu
IchJinCet
utadwulb
ethFench

    Generate only one with no delimiter:

    # apg -c random_seed -n 1 -d
AkKijNayn

    Spell the generated passwords:

    # apg -c random_seed -n 1 -d
aicWajbyRorp42863:~# apg -c random_seed -l
FrogQuev Foxtrot-romeo-oscar-golf-Quebec-uniform-echo-victor
cecNeiv1 charlie-echo-charlie-November-echo-india-victor-ONE
SkudVolt Sierra-kilo-uniform-delta-Victor-oscar-lima-tango
TowUlripab Tango-oscar-whiskey-Uniform-lima-romeo-india-papa-alfa-bravo
Bytquigpey Bravo-yankee-tango-quebec-uniform-india-golf-papa-echo-yankee
Doithneb Delta-oscar-india-tango-hotel-november-echo-bravo
    • 4

  3. You may try 'pwgen' (available in Ubuntu/Debian/Gentoo etc.)

    Generate a 10 char password:

    pwgen 10

    Generate a more secure 10 char password:

    pwgen -s 10

    Generate a 'really' secure 10 char password:

    pwgen -sy 10

    Hope this helps, Cheers

    • 2

  4. The following generates a unique 8 lower and upper character password: openssl rand -base64 6

    • 2 
  5. mkpasswd -l 10
# will make a randon password with 10 chars - you may need to install it ...
    • 1 
  6. #Chars allowed in password (I don't like l,o,O, etc):
P="0123456789ABCDEFGHIJKLMNPQRSTUVWXYZabcdefghijkmnpqrstuvwxyz"

#Or such:
#P="a-zA-Z0-9"

#The string pasted as $P$P$P... must be at least 256 chars long.

head -c 8 < /dev/urandom | tr '\000-\377' "$P$P$P$P$P"
echo
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  7. If you're creating a password a human should remember, pick a few random words from a dictionary:

    $ uniq < /usr/share/dict/words | shuf | head -n 4 | tr '\n' ' ' reinitialise content snug dimly

    Relevant XKCD strip

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