+++ /dev/null
-#!/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:
-#
-# - 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.
-#
-# - This step uses `bc` to calculate a logarithm float string
-# and `awk` to convert the float into an integer, rounding up.
-#
-# - Use `tr`, `/dev/urandom`, and `head` to generate a random
-# alphanumeric string with the length calculated in the previous
-# step.
-#
-# - Use `echo` to display the passphrase in stdout with a trailing
-# newline.
-#
-# Dependencies: bash, echo, bc, awk, tr, head. See end of file
-#
-# Tested on:
-#
-# - GNU/Linux Debian 10
-
-
-#==Initialization==
-
-let ALPHABET_SIZE="26+26+10" # number of unique chars in [:alnum:], argument fed to `tr -c` in 'Generate passphrase' step)
-LOG_BASE=2 # Set logarithm base to 2
-
-# Define `echoerr` function which outputs text to stderr
- # Note: function copied from https://stackoverflow.com/a/2990533
-function echoerr {
- 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/
-function rpass {
- cat /dev/urandom | LC_ALL=C tr -cd "[:alnum:]" | 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
-if [ -z "$1" ]
-then
- echo "Entropy bit count argument (\$1) not supplied."
- # Get from user the number of bits of entropy.
- echoerr -n "Please specify the required strength of the password in bits of entropy (ex: 256):" # prompt via stderr
- read ENTROPY_BIT_COUNT1
-else
- ENTROPY_BIT_COUNT1="$1"
-fi
-
-# Check if $ENTROPY_BIT_COUNT1 is an non-negative integer
- # Note: Regular expression test is adapted from https://stackoverflow.com/a/806923
-RETEST1='^[0-9]+$'
-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
-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.
-
-# Round $CHAR_COUNT1_FLOAT1 up to next highest integer for use as argument in later bash functions.
- # Note: awk expression from https://bits.mdminhazulhaque.io/linux/round-number-in-bash-script.html
-CHAR_COUNT1=$(echo "$CHAR_COUNT1_FLOAT" | awk '{print ($0-int($0)>0)?int($0)+1:int($0)}')
-
-# Generate passphrase
-PASS1=$(rpass "$CHAR_COUNT1")
-echo -e "$PASS1"
-
-
-#==References==
-#
-# - How to echo a string as stderr instead of stdout.
-# https://stackoverflow.com/a/2990533
-# Author: James Roth
-# Date: 2010-06-07T14:52Z
-# Date Accessed: 2020-01-20
-#
-# - How to check if script argument exists or not.
-# https://stackoverflow.com/a/6482403
-# Author: phoxix
-# Date: 2011-06-26T05:55Z
-# Date Accessed: 2020-01-20
-#
-# - How to check that a string is an integer using regular expression test.
-# https://stackoverflow.com/a/806923
-# Author: Charles Duffy
-# Date: 2009-04-30T13:32Z
-# Date Accessed: 2020-01-20
-#
-# - How to use `bc` to calculate logarithms in Bash
-# http://phodd.net/gnu-bc/bcfaq.html#bashlog
-# Author: unknown
-# Date Accessed: 2020-01-20
-#
-# - How to use `awk` to convert and round up a float to an integer.
-# https://bits.mdminhazulhaque.io/linux/round-number-in-bash-script.html
-# Author: Md. Minhazul Haque
-# Date: 2015-01-09
-# Date Accessed: 2020-01-20
-#
-# - How to use `/dev/urandom`, `tr`, and `head` to generate a random password in Bash.
-# https://www.thegeekstuff.com/2010/04/unix-bash-function-examples/
-# Author: SASIKALA, Ramesh Natarajan
-# Date: 2010-04-21
-# Date Accessed: 2020-01-20
-#
-# - Dependencies: bash, echo, bc, awk, tr, head.
-#
-# - GNU bash, version 5.0.3(1)-release (x86_64-pc-linux-gnu)
-# Copyright (C) 2019 Free Software Foundation, Inc.
-# License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
-# This is free software; you are free to change and redistribute it.
-# There is NO WARRANTY, to the extent permitted by law.
-#
-# - echo (GNU coreutils) 8.30
-# Copyright (C) 2018 Free Software Foundation, Inc.
-# License GPLv3+: GNU GPL version 3 or later <https://gnu.org/licenses/gpl.html>.
-# This is free software: you are free to change and redistribute it.
-# There is NO WARRANTY, to the extent permitted by law.
-#
-# Written by Brian Fox and Chet Ramey.
-#
-# - bc 1.07.1
-# Copyright 1991-1994, 1997, 1998, 2000, 2004, 2006, 2008, 2012-2017 Free Software Foundation, Inc.
-#
-# - GNU Awk 4.2.1, API: 2.0 (GNU MPFR 4.0.2, GNU MP 6.1.2)
-# Copyright (C) 1989, 1991-2018 Free Software Foundation.
-#
-# 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
-# (at your option) 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.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program. If not, see http://www.gnu.org/licenses/.
-#
-# - tr (GNU coreutils) 8.30
-# Copyright (C) 2018 Free Software Foundation, Inc.
-# License GPLv3+: GNU GPL version 3 or later <https://gnu.org/licenses/gpl.html>.
-# This is free software: you are free to change and redistribute it.
-# There is NO WARRANTY, to the extent permitted by law.
-#
-# Written by Jim Meyering.
-#
-# - head (GNU coreutils) 8.30
-# Copyright (C) 2018 Free Software Foundation, Inc.
-# License GPLv3+: GNU GPL version 3 or later <https://gnu.org/licenses/gpl.html>.
-# This is free software: you are free to change and redistribute it.
-# There is NO WARRANTY, to the extent permitted by law.
-#
-# Written by David MacKenzie and Jim Meyering.
projects / BK-2020-03.git / blobdiff