Minimal Digital Safe (for dummies). Download the file, then make it executable: chmod +x ./mindisafe

mindisafe

#/usr/bin/env bash
# Brief: Minimal Digital Safe (MinDiSafe)
# Usage: mindisafe <path>

trap 'eval ${reset}' exit

keygen(){
  echo -n "Safe: Enter Mother's maiden name (case-insensitive): "
  read -r salt || return 1
  echo -n "Safe: Enter your passkey now: "
  read -r pass || return 1
  tput cuu 2 ; tput ed ; echo "Safe: Got the creds :)"
  key=$(echo -n "${pass}" | "${argon2}" "mindisafe${salt,,*}" -i -t 12 -m 17 -p 4 -l 32 -r)
}

cmd="${0} ${@}"
path="${@}"
[[ -n "${path}" ]] || read -erp "Safe: Drag-n-drop file here - " path || exit 1
path="${path/#\"/}" ; path="${path/%\"/}" # Quote (") removal, if any
converted="$(wslpath "${path}" 2>/dev/null)"
path="${converted:="${path}"}"
path="${path/#~\//${HOME}\/}" # Tilde expansion
path="${path/#~-\//${OLDPWD}\/}" # Tilde expansion
[[ -f "${path}" ]] || { echo "Error: ${path} doesn't exist"; exit 1;}

argon2="$(which argon2)" ; argon2="${argon2:="${HOME}/.argon2.mindisafe"}"
if ! [[ -x "${argon2}" ]]; then
  echo "Safe: argon2 not installed. Need to download it. Check your internet connection and then press any key: "
  read -sn1
  echo -n "Safe: Wait..."
  curl -sSNfL -o "${argon2}" \
  "https://github.com/SomajitDey/phc-winner-argon2/releases/download/static-build_linux_x86_64/argon2" \
  || { echo "Error: argon2 binary couldn't be downloaded"; exit 1;}
  chmod +x "${argon2}"
  echo -e "\rSafe: argon2 obtained. Proceeding."
fi

tmp=$(mktemp -u .mindisafeXXXXXX); reset="${reset:-:} ; rm -f ${tmp}"
if grep -zq "^.*BEGIN PGP MESSAGE.*END PGP MESSAGE.*$" "${path}"; then
  echo "Safe: You provided a lockedfile. So let's unlock it."
  keygen || exit 1
  PS3="Safe: Type 1 or 2 - "$'\n'
  echo "Safe: Now, do you want to" 
  select opt in "unlock the file permanently" "just see the contents here";do
    case "${REPLY}" in
      1)
        cp "${path}" "${tmp}" || exit "${?}"
        gpg --batch -q --pinentry-mode loopback --passphrase "${key}" -d "${path}" > "${tmp}" && \
        mv "${tmp}" "${path}" && \
        echo "Safe: Done. To lock the file again, simply: ${cmd}"
        break
        ;;
      2) 
        tput smcup
          echo -e "Safe: Here is your data. No worries, the file has been kept locked. Press anykey when you are ready to exit.\n\n"
          gpg --batch -q --pinentry-mode loopback --passphrase "${key}" -a -o - -d "${path}"
          read -sn1
          tput rmcup
        break
        ;;
    esac
  done
else
  echo "Safe: You provided an unlocked file. So let's lock it."
  keygen || exit 1
  gpg --batch -q --pinentry-mode loopback --passphrase "${key}" -a -o "${tmp}" -c "${path}" && \
  mv "${tmp}" "${path}" && \
  echo "Safe: File locked. To unlock the file, simply: ${cmd}"
  echo -n "Safe: Do you need a download link for the locked file (internet connectivity required)? (y/n): "
  read -n1; echo
  case "${REPLY,,*}" in
    y) echo "Safe: Uploading..." ; echo "Safe: $(curl -sSfN -T "${path}" https://transfer.sh)";;
    n) tput cuu1; tput ed;;
    *) echo "Safe: You didn't type y so assuming n. Ok bye then";;
  esac
fi