mkpwd

1. Content (this section)
2. Installation
3. Development
4. Algorithm
5. Security

mkpwd is a password generating program. It is designed to satisfy a scalable range of security demands.

It's standard behavior is to generate one password consisting of any of all printable ASCII characters (32-128) with a length between 6 and 10.

You can modify the way passwords are generated via command-line switches. You can specify a length range, the characters used and even let mkpwd generate passwords which are kind of readable and therefore easier to remember (and easier to crack either, see below). mkpwd was tested under Solaris, FreeBSD and Linux.

Download the source and untar the package.
Change to the created directory and type:

# ./configure

# make and

# make install

That's all.

The sources are kept in a repository on sourceforge. Just checkout the sources:

git clone git://git.code.sf.net/p/mkpwd/code mkpwd

and send me diffs ;)

The algorithm is based on the systems rand()-function (see man 3 rand) and therefore depends heavily on it's implementation. I did some testing on the output of mkpwd which is represented in the table below. I let mkpwd generate 100000 passwords with the parameters listed below. The `*' run was performed using a script-file which started mkpwd 10 times at once (i.e. nearly, started in background) and evaluated the output of all 10 instances. The numbers in the table are the numbers printed by 'uniq -d'.

t1: -n 10 -m 10 -t 3 -l (fixed length 10, alpha)
t2: -t 5 (alphanum-readable)
t3: -t 6 (alpha-readable)
t4: -n 6 -m 6 -t 5 (fixed length 6, aplhanum-readable)
t5: -n 6 -m 6 -t 6 (fixed length 6, alpha-readable)
t6: -n 6 -m 6 -t 5 -l (same as t4, lowercase only)
t7: -n 6 -m 6 -t 6 -l (same as t5, lowercase only)
t8: -t 4 (numeric-only)
t9: -n 10 -m 10 -t 4 (fixed length 10, numeric-only)

As you can see one gets a lot of doubles if the password length is fixed, especialy if you use a short length.

Generally it is advisable to use only passwords which are generated by mkpwd in it's default mode. If you use options to get rememberable ones, you also make it easier for password cracking programms to guess them. Read 'man 1 passwd' to learn more about passwords and security. If someone would try to crack passwords (e.g. with john) which were generated with mkpwd with different options I would be appriciated to see the results.