Differences between version 17 and revision by previous author of ChoosingPasswords.
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| Newer page: | version 17 | Last edited on Sunday, December 26, 2004 4:26:31 pm | by CraigBox | Revert |
| Older page: | version 15 | Last edited on Sunday, December 19, 2004 5:59:08 pm | by AristotlePagaltzis | Revert |
@@ -1,24 +1,48 @@
-PerryLorier's prefered and highly recommended way of choosing passwords:
+!!
PerryLorier's prefered and highly recommended way of choosing passwords
<pre>
-<
/dev/urandom tr -cd
'~[:print:]
' | head
-c
20 ''# every time you waste a cat, god kills a kitten''
+ cat
/dev/urandom |
tr -dc
' -
~' | fold
-w
20 | head -1
</pre>
His new password is <tt>_]}e9pgU5-u6_hr~[KF|*</tt>.
+
+!What this does
+
+/dev/urandom is an interface to the kernel's random number generator. If you cat it, you'll get (mostly) random characters. See random(4) for information.
+
+tr(1) is a character translator. -d stands for 'delete characters in this set' and -c stands for 'compliment'. If you check ascii(7) you will see that space and tilde (~) are the outer limits of the 'typeable' ASCII character set. The translator stage will throw away anything lower than space or higher than tilde (all the high-bit ASCII character).
+
+fold(1) wraps lines to a certain width. -w 20 wraps at 20 characters (the default is 80.) Mere mortals will probably want to set this to around 8.
+
+head(1) (the opposite of tail(1)) returns the first lines of an input. head -1 returns only the first line. (use head -n 8 if you want some choices to pick from).
+
+!But but but
+
+If you're a real Unix nerd or are worried that using another process for ''cat(1)'' will only accelerate our path to the heat death of the universe, you can use
+
+<pre>
+< /dev/urandom tr -cd '~[:print:]' | head -c 20 ''# every time you waste a cat, god kills a kitten''
+</pre>
+
+!Variants
AristotlePagaltzis prefers slightly less cryptic passwords that are longer instead, which results in
<verbatim>
#!/bin/sh
< /dev/urandom tr -cd '[:alnum:]$!@_:=-' | head -c "${1:-32}"
echo
</verbatim>
+
+!!Other methods
Another popular method is to take the first letter of each word in a line from a song (eg ''I want to ride my bicycle'' -> <tt>iw2rmb</tt>)
+
+Pick a password that sounds like an English word, and people are more likely to remember it. A good Java password generator can be found at http://www.multicians.org/thvv/gpw.html.
If none of these methods are to your liking, you can always set your password to <tt>gandalf</tt>. This is highly original, and noone is likely to think of it.
You might find more information on the SecurityNotes page.
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CategorySecurity
