technology blog

Friday, 11 March 2011

Generating passwords

Note to myself as I always forget. How to generate a (mostly) uncrackable password:
sudo apt-get install apg
apg -m 9 -MLNS -a0 -t
This request: min 9 chars, must contain lowercase,  numeral, and symbol, be pronounceable, and print the pronunciation.


  • Prepend /! for irc&bash safety.
  • Append any accented letter in (non-exclusive) çÇ àÀ­áÁäÄâ éÉèÈëËêÊ íÍìÌïÏîÎ óÓòÒöÖôÔ úÚùÙüÜûÛ ýÝÿ ±£¢¤¬¦²³¼½¾¶§µ¯­­­. All these letters can be seamlessly typed from a FR-CA keyboard with AltGr or two keys combination.
    • You can simplify the apg complexity because of this one since it's adding many letters of entropy and each of these letters is ~3 bytes of utf-8, dramatically increasing the effective password length.
    • If you are selecting your password on linux, don't forget that Windows won't accept certain combinations like ȩȨ ÝŸŷŶ. You may want to not use them if you ever plan to login from a windows workstation.
    • «»° aren't accessible on all FR-CA keyboard so you need to memorize the Alt-Numlock combination.
    • Similar alternatives for Spanish people: ¿¡
  • You now have a password that:
    • is mostly copy-paste safe
    • is uncrackable by most rainbow tables. Who generates a utf8 rainbow table with ½ or µ with length of 12 characters?
    • will probably not be accepted by most web sites since it's too secure. :(