Forgot password option bash script

Question

I am trying to make a bash script that will generate a password. The script also has a "Forgot password" option. Because the password has random characters, it's hard to remember, so when a user forgets the pass it can be regenerated but, of course, there have to be security questions.

I figured out the part where I can ask a user 3 questions and generate a password. For example: username, favorite food and url. The part I can't seem to figure out is where a user can regenerate the password. I think I need to somehow store 3 variables (username, favoriteFood, url) but I have no idea how. This is the code that I have:

#!/bin/bash

pause(){
  read -p "Press [Enter] key to continue..." fackEnterKey
}

one(){
    echo "Enter your usename"
    read username
    echo "Whats your favorite food"
    read favoriteFood
    echo "Enter URL"
    read url
    choose() { echo ${1:RANDOM%${#1}:1} $RANDOM; }
        pass="$({ choose '!@#$%^\&'
        choose '0123456789'
        choose 'abcdefghijklmnopqrstuvwxyz'
        choose 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
        for i in $( seq 1 $(( 4 + RANDOM % 8 )) )
            do
                choose '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ'
            done
        } | sort -R | awk '{printf "%s",$1}')"
    echo "Your pass is:"$pass    
    pause
}
#this is the part where i am stuck 
two(){
    echo "Enter username"
    read username2
    echo "Whats your favorite food"
    read favoriteFood2
    echo "Enter URL"
    read url2
    if [ username==username2 -a favoriteFood==favoriteFood2 -a url==url2 ] #this only works if the scirpt is not closed.
        then 
            echo $pass
        else
            echo "not found"
    fi        
        pause
}

show_menus() {
    clear
    echo "~~~~~~~~~~~~~~~~~~~~~"    
    echo " M A I N - M E N U"
    echo "~~~~~~~~~~~~~~~~~~~~~"
    echo "1. Generate password"
    echo "2. Forgot password"
    echo "3. Exit"
}
read_options(){
    local choice
    read -p "Enter choice [ 1 - 3] " choice
    case $choice in
        1) one ;;
        2) two ;;
        3) exit 0;;
        *) echo -e "${RED}Error...${STD}" && sleep 2
    esac
}
trap '' SIGINT SIGQUIT SIGTSTP
while true
do

    show_menus
    read_options
done

Answer 1

If you want to be able to reproduce the same generated password if the user enters the same 3 answers again, just don't create a random password but derive the password from the answers only. That way your password is no longer truly random but only pseudo-random (seems random to humans, but is determined by the input only), but that's likely a smaller security problem than storing the passwords in plain-text in a password database.

I've written a short example that takes in 3 answers $answer1, $answer2, $answer3 and a numeric $length parameter that determines the output password length (max. 86 characters):

$ answer1=bytecommander
$ answer2=pizza
$ answer3=askubuntu.com
$ length=12

$ printf '%s-%s-%s%n' "$answer1" "$answer2" "$answer3" | sha512sum | xxd -r -p | base64 -w0 | grep -Eo "^.{$length}"
fBuIlC+lXiuW

The command looks complicated, but how it works is actually pretty easy:

• printf '%s-%s-%s%n' "$answer1" "$answer2" "$answer3" simply concatenate the three answer strings together using - as delimiter and adding a newline. You can use any other method that converts your user input into one single string, it doesn't matter as long as you just always use the same.
• sha512sum reads from standard input (where the output of the command above is piped) and calculates the SHA-512 hash of it. This is a string of 129 hexadecimal (0-9, a-f) characters.
• xxd -r -p converts the hexadecimal characters to binary code.
• base64 -w0 converts the binary code to Base 64 (a-z, A-Z, 0-9, +, /).
• grep -Eo "^.{$length}" prints the first $length characters of the result. You should not specify a length greater than 86 (there are 88 characters, but the last two will always be ==).