encrypt-transfer.sh

#!/bin/bash

set -e

if ! [[ -x "$(command -v curl 2> /dev/null)" ]]; then
    echo >&2 "No curl command"
    exit 1
fi

if ! [[ -x "$(command -v openssl 2> /dev/null)" ]]; then
    echo >&2 "No openssl command"
    exit 1
fi

randpw() { tr -dc _A-Z-a-z-0-9 < /dev/urandom  | head -c16; }
transfer() { curl --progress-bar --upload-file "$1" "https://transfer.sh/$2" | tee /dev/null; }

case "$1" in
    -e|--encrypt)
        shift

        if [[ -z "$1" ]]; then
            echo >&2 "File name is missing"
            exit 1
        fi

        if [[ -z "$PASSWORD" ]]; then
            PASSWORD=$(randpw)
            echo "Use random password: $PASSWORD"
        else
            echo "Use password from PASSWORD environment variable"
        fi

        transfer <(openssl enc -aes-256-cbc -md sha256 -kfile <(echo -n "$PASSWORD") -in "$1") "$(basename "$1")"
        echo
        ;;
    -d|--decrypt)
        shift

        if [[ -z "$PASSWORD" ]]; then
            echo -n Password:
            read -rs PASSWORD
            echo
            if [[ -z "$PASSWORD" ]]; then
                echo >&2 "Password is empty"
                exit 1
            fi
        fi

        DEST_FN=$(basename "$1")
        if [[ -e "$DEST_FN" ]]; then
            DEST_FN=$(mktemp -p "$PWD" -t "${DEST_FN}.XXXXXX")
        fi

        curl -s "$1" | openssl enc -d -aes-256-cbc -md sha256 -kfile <(echo -n "$PASSWORD") -out "$DEST_FN"
        echo "Decrypted file: $DEST_FN"
        ;;
    -h|--help|*)
        echo "Usage:"
        echo " -e|--encrypt file-name   Encrypt and transfer"
        echo " -d|--decrypt   url         Download and decrypt (password must be in PASSWORD environment variable)"
        echo " -h|--help                  Print this"
        exit 0
        ;;
esac