bcrypt - xor obfuscation in bash

bcrypt.sh

#!/usr/bin/env shell-helpers

# bcrypt - simple obfuscation through xor
#          NOT safe for cryptographic use.
# @requires shell-helpers (https://github.com/briceburg/shell-helpers)
#
# example usage:
#   cat source.txt | bcrypt > source.txt.crypt
#   cat source.txt.crypt | bcrypt > source.txt.decrypted
#   diff source.txt source.txt.decrypted || echo "there was an error!"

crypt(){
  [ -n "$1" ] || die "please provide input stdin or through arguments"

  header="${BCRYPT_HEADER:-"~bCryPt~"}"
  if [ "${1:0:${#header}}" = "$header" ]; then
    cint="$(( ${1:${#header}:2} / 3))"
    set -- "${1:$((${#header} + 2))}"
    xor "$1" "$cint" | base64 -d
  else
    # select a random cint and print header
    cints=( 21 22 23 24 25 26 27 28 29 30 31 )
    cint=${cints[$RANDOM % ${#cints[@]}]}
    printf "${header}$(( $cint * 3 ))"
    xor "$(echo "$1" | base64)" "$cint" $encode
  fi
}

xor(){
  input="$1"
  cint="${2:-31}"
  output=""
  for ((i=0; i<${#1}; i++)); do
    printf -v ord "%d" "'${input:$i:1}"
    printf -v tmp '%03o' "$((ord ^ $cint))"
    printf -v tmp "\\$tmp"
    output+="$tmp"
  done
  echo "$output"
}

crypt "$(io/cat $@)"