#!/bin/bash
-
-# Date: 2020-01-20T16:34Z
-#
-# Author: Steven Baltakatei Sandoval (baltakatei.com)
-#
-# License: This bash script, `bknpass`, is licensed under GPLv3 or
-# later by Steven Baltakatei Sandoval:
-#
-# `bknpass`, an alphanumeric password generator
-# Copyright (C) 2020 Steven Baltakatei Sandoval (baltakatei.com)
-#
-# This program is free software: you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation, either version 3 of the License, or
-# any later version.
-#
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-# GNU General Public License for more details.
-#
-# A copy of the GNU General Public License may be found at
-# <https://www.gnu.org/licenses/>.
-#
-# Description: This bash script generates alphanumeric passphrases
-# with a char-count determined by a user-provided number of bits of
-# entropy. The passphrase is then outputted to stdout with a trailing
-# newline. It works as follows:
+# Desc: Generate alphanumeric passphrase with specified bits of entropy.
+# Usage: bknpass [int]
+# Example: bknpass 128
+# Depends: bash, echo, bc, awk, tr, head, Debian 10
+# Version: 0.1.0
+# Note: This bash script generates alphanumeric passphrases
+# with a char-count determined by a user-provided number of bits of
+# entropy. The passphrase is then outputted to stdout with a trailing
+# newline. It works as follows:
#
-# - Prompt user for an integer. This integer is the number of bits
-# of entropy that the generated password should have.
-#
-# - Check if user-provided string is an integer using `bash` regular
-# expression test.
-#
-# - Calculate the minimum number of alphanumeric characters required
-# to encode the specified number of bits of entropy.
+# - Prompt user for an integer. This integer is the number of bits
+# of entropy that the generated password should have.
#
-# - This step uses `bc` to calculate a logarithm float string
-# and `awk` to convert the float into an integer, rounding up.
+# - Check if user-provided string is an integer using `bash` regular
+# expression test.
#
-# - Use `tr`, `/dev/urandom`, and `head` to generate a random
-# alphanumeric string with the length calculated in the previous
-# step.
+# - Calculate the minimum number of bech32 base32 characters
+# required to encode the specified number of bits of entropy.
#
-# - Use `echo` to display the passphrase in stdout with a trailing
-# newline.
+# - This step uses `bc` to calculate a logarithm float string
+# and `awk` to convert the float into an integer, rounding up.
#
-# Dependencies: bash, echo, bc, awk, tr, head. See end of file
+# - Use `tr`, `/dev/urandom`, and `head` to generate a random
+# alphanumeric string with the length calculated in the previous
+# step.
#
-# Tested on:
-#
-# - GNU/Linux Debian 10
+# - Use `echo` to display the passphrase in stdout with a trailing
+# newline.
#==Initialization==
-let ALPHABET_SIZE="26+26+10" # number of unique chars in [:alnum:], argument fed to `tr -c` in 'Generate passphrase' step)
+let ALPHABET_SIZE="32" # number of unique chars in bech32 base32 charset
LOG_BASE=2 # Set logarithm base to 2
# Define `echoerr` function which outputs text to stderr
echo "$@" 1>&2;
}
-# Define `rpass` function which generates an alphanumeric passphrase of length $1 (ex: `rpass 22` generates a 22-char string)
- # Note: function adapted from https://www.thegeekstuff.com/2010/04/unix-bash-function-examples/
+# Define `rpass` function which generates a base32 passphrase of length $1 (ex: `rpass 20` generates a 20-char string)
+# Note: function adapted from https://www.thegeekstuff.com/2010/04/unix-bash-function-examples/
+# Note: base32 charset uses bech32 charset
function rpass {
- cat /dev/urandom | LC_ALL=C tr -cd "[:alnum:]" | head -c ${1:-22}
+ cat /dev/urandom | LC_ALL=C tr -cd "qpzry9x8gf2tvdw0s3jn54khce6mua7l" | head -c ${1:-22}
}
#==Main Program==
# Define $ENTROPY_BIT_COUNT1 as argument $1 or prompt user if $1 is not defined.
- # note: argument test adapted from https://stackoverflow.com/a/6482403
+# Note: argument test adapted from https://stackoverflow.com/a/6482403
if [ -z "$1" ]
then
echo "Entropy bit count argument (\$1) not supplied."
fi
# Check if $ENTROPY_BIT_COUNT1 is an non-negative integer
- # Note: Regular expression test is adapted from https://stackoverflow.com/a/806923
+# Note: Regular expression test is adapted from https://stackoverflow.com/a/806923
RETEST1='^[0-9]+$'
if ! [[ $ENTROPY_BIT_COUNT1 =~ $RETEST1 ]] ; then
echo "error: Not an integer." >&2; exit 1
fi
# Calculate minimum count of chars needed to encode $ENTROPY_BIT_COUNT1 with alphabet size of $ALPHABET_SIZE as float
- # Solve ln(a^n)/ln(2)=b for n using `bc` where
- # a=$ALPHABET_SIZE
- # n=$CHAR_COUNT1_FLOAT
- # b=$ENTROPY_BIT_COUNT1
- # Note: `bc` logarithm usage adapted from http://phodd.net/gnu-bc/bcfaq.html#bashlog
+# Solve ln(a^n)/ln(2)=b for n using `bc` where
+# a=$ALPHABET_SIZE
+# n=$CHAR_COUNT1_FLOAT
+# b=$ENTROPY_BIT_COUNT1
+# Note: `bc` logarithm usage adapted from http://phodd.net/gnu-bc/bcfaq.html#bashlog
CHAR_COUNT1_FLOAT=$(echo "$ENTROPY_BIT_COUNT1*l($LOG_BASE)/l($ALPHABET_SIZE)" | bc -l)
- # Note: Float will be of form "21.49744370650136860806". This particular float should be rounded to "22" later.
+# Note: Float will be of form "21.49744370650136860806".
+# Note: This particular example float should be rounded to "22" later.
# Round $CHAR_COUNT1_FLOAT1 up to next highest integer for use as argument in later bash functions.
- # Note: awk expression from https://bits.mdminhazulhaque.io/linux/round-number-in-bash-script.html
+# Note: awk expression from https://bits.mdminhazulhaque.io/linux/round-number-in-bash-script.html
CHAR_COUNT1=$(echo "$CHAR_COUNT1_FLOAT" | awk '{print ($0-int($0)>0)?int($0)+1:int($0)}')
# Generate passphrase
# Date: 2010-04-21
# Date Accessed: 2020-01-20
#
+# - Bech32 base32 charset
+# https://github.com/bitcoin/bips/blob/master/bip-0173.mediawiki
+# Author: Pieter Wuille <pieter.wuille@gmail.com>
+# Date: 2017-03-20
+# License: BSD-2-Clause
+# Date: Accessed: 2021-01-23
+#
# - Dependencies: bash, echo, bc, awk, tr, head.
#
# - GNU bash, version 5.0.3(1)-release (x86_64-pc-linux-gnu)
# There is NO WARRANTY, to the extent permitted by law.
#
# Written by David MacKenzie and Jim Meyering.
+
+# Author: Steven Baltakatei Sandoval
+# License: GPLv3+
projects / BK-2020-03.git / blobdiff