mirror of
https://github.com/ohmyzsh/ohmyzsh.git
synced 2024-11-30 09:40:09 +00:00
68 lines
1.7 KiB
Bash
Executable file
68 lines
1.7 KiB
Bash
Executable file
#!/usr/bin/env zsh
|
|
#
|
|
# Usage: genpass-xkcd [NUM]
|
|
#
|
|
# Generate a password made of words from /usr/share/dict/words
|
|
# with the security margin of at least 128 bits.
|
|
#
|
|
# Example password: 9-mien-flood-Patti-buxom-dozes-ickier-pay-ailed-Foster
|
|
#
|
|
# If given a numerical argument, generate that many passwords.
|
|
#
|
|
# The name of this utility is a reference to https://xkcd.com/936/.
|
|
|
|
emulate -L zsh -o no_unset -o warn_create_global -o warn_nested_var -o extended_glob
|
|
|
|
if [[ ARGC -gt 1 || ${1-1} != ${~:-<1-$((16#7FFFFFFF))>} ]]; then
|
|
print -ru2 -- "usage: $0 [NUM]"
|
|
return 1
|
|
fi
|
|
|
|
zmodload zsh/system zsh/mathfunc || return
|
|
|
|
local -r dict=/usr/share/dict/words
|
|
|
|
if [[ ! -e $dict ]]; then
|
|
print -ru2 -- "$0: file not found: $dict"
|
|
return 1
|
|
fi
|
|
|
|
# Read all dictionary words and leave only those made of 1-6 characters.
|
|
local -a words
|
|
words=(${(M)${(f)"$(<$dict)"}:#[a-zA-Z](#c1,6)}) || return
|
|
|
|
if (( $#words < 2 )); then
|
|
print -ru2 -- "$0: not enough suitable words in $dict"
|
|
return 1
|
|
fi
|
|
|
|
if (( $#words > 16#7FFFFFFF )); then
|
|
print -ru2 -- "$0: too many words in $dict"
|
|
return 1
|
|
fi
|
|
|
|
# Figure out how many words we need for 128 bits of security margin.
|
|
# Each word adds log2($#words) bits.
|
|
local -i n=$((ceil(128. / (log($#words) / log(2)))))
|
|
|
|
{
|
|
local c
|
|
repeat ${1-1}; do
|
|
print -rn -- $n
|
|
repeat $n; do
|
|
while true; do
|
|
# Generate a random number in [0, 2**31).
|
|
local -i rnd=0
|
|
repeat 4; do
|
|
sysread -s1 c || return
|
|
(( rnd = (~(1 << 23) & rnd) << 8 | #c ))
|
|
done
|
|
# Avoid bias towards words in the beginning of the list.
|
|
(( rnd < 16#7FFFFFFF / $#words * $#words )) || continue
|
|
print -rn -- -$words[rnd%$#words+1]
|
|
break
|
|
done
|
|
done
|
|
print
|
|
done
|
|
} </dev/urandom
|