ohmyzsh/plugins/genpass/genpass.plugin.zsh
2020-12-14 15:52:30 +01:00

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autoload -U regexp-replace
zmodload zsh/mathfunc
genpass-apple() {
# Generates a 128-bit password of 6 pseudowords of 6 characters each
# EG, xudmec-4ambyj-tavric-mumpub-mydVop-bypjyp
# Can take a numerical argument for generating extra passwords
local -i i j num
[[ $1 =~ '^[0-9]+$' ]] && num=$1 || num=1
local consonants="$(LC_ALL=C tr -cd b-df-hj-np-tv-xz < /dev/urandom \
| head -c $((24*$num)))"
local vowels="$(LC_ALL=C tr -cd aeiouy < /dev/urandom | head -c $((12*$num)))"
local digits="$(LC_ALL=C tr -cd 0-9 < /dev/urandom | head -c $num)"
# The digit is placed on a pseudoword edge using $base36. IE, Dvccvc or cvccvD
local position="$(LC_ALL=C tr -cd 056bchinotuz < /dev/urandom | head -c $num)"
local -A base36=(0 0 1 1 2 2 3 3 4 4 5 5 6 6 7 7 8 8 9 9 a 10 b 11 c 12 d 13 \
e 14 f 15 g 16 h 17 i 18 j 19 k 20 l 21 m 22 n 23 o 24 p 25 q 26 r 27 s 28 \
t 29 u 30 v 31 w 32 x 33 y 34 z 35)
for i in {1..$num}; do
local pseudo=""
for j in {1..12}; do
# Uniformly iterate through $consonants and $vowels for each $i and $j
# Creates cvccvccvccvccvccvccvccvccvccvccvccvc for each $num
pseudo="${pseudo}${consonants:$((24*$i+2*${j}-26)):1}"
pseudo="${pseudo}${vowels:$((12*$i+${j}-13)):1}"
pseudo="${pseudo}${consonants:$((24*$i+2*${j}-25)):1}"
done
local -i digit_pos=${base36[${position[$i]}]}
local -i char_pos=$digit_pos
# The digit and uppercase character must be in different locations
while [[ $digit_pos == $char_pos ]]; do
char_pos=$base36[$(LC_ALL=C tr -cd 0-9a-z < /dev/urandom | head -c 1)]
done
# Places the digit on a pseudoword edge
regexp-replace pseudo "^(.{$digit_pos}).(.*)$" \
'${match[1]}${digits[$i]}${match[2]}'
# Uppercase a random character (that is not a digit)
regexp-replace pseudo "^(.{$char_pos})(.)(.*)$" \
'${match[1]}${(U)match[2]}${match[3]}'
# Hyphenate each 6-character pseudoword
regexp-replace pseudo '^(.{6})(.{6})(.{6})(.{6})(.{6})(.{6})$' \
'${match[1]}-${match[2]}-${match[3]}-${match[4]}-${match[5]}-${match[6]}'
printf "${pseudo}\n"
done
}
genpass-monkey() {
# Generates a 128-bit base32 password as if monkeys banged the keyboard
# EG, nz5ej2kypkvcw0rn5cvhs6qxtm
# Can take a numerical argument for generating extra passwords
local -i i num
[[ $1 =~ '^[0-9]+$' ]] && num=$1 || num=1
local pass=$(LC_ALL=C tr -cd '0-9a-hjkmnp-tv-z' < /dev/urandom \
| head -c $((26*$num)))
for i in {1..$num}; do
printf "${pass:$((26*($i-1))):26}\n"
done
}
genpass-xkcd() {
# Generates a 128-bit XKCD-style passphrase
# e.g, 9-mien-flood-Patti-buxom-dozes-ickier-pay-ailed-Foster
# Can take a numerical argument for generating extra passwords
if (( ! $+commands[shuf] )); then
echo >&2 "$0: \`shuf\` command not found. Install coreutils (\`brew install coreutils\` on macOS)."
return 1
fi
if [[ ! -e /usr/share/dict/words ]]; then
echo >&2 "$0: no wordlist found in \`/usr/share/dict/words\`. Install one first."
return 1
fi
local -i i num
[[ $1 =~ '^[0-9]+$' ]] && num=$1 || num=1
# Get all alphabetic words of at most 6 characters in length
local dict=$(LC_ALL=C grep -E '^[a-zA-Z]{1,6}$' /usr/share/dict/words)
# Calculate the base-2 entropy of each word in $dict
# Entropy is e = L * log2(C), where L is the length of the password (here,
# in words) and C the size of the character set (here, words in $dict).
# Solve for e = 128 bits of entropy. Recall: log2(n) = log(n)/log(2).
local -i n=$((int(ceil(128*log(2)/log(${(w)#dict})))))
for i in {1..$num}; do
printf "$n-"
printf "$dict" | shuf -n "$n" | paste -sd '-'
done
}