How to encrypt and decrypt strings on Linux using Openssl (v0.2)

If you're looking for a secure way to encrypt and decrypt strings on Linux, Openssl is a great tool to use. In my previous blog post, I introduced a script for this purpose, but I've recently made some enhancements to improve its security.

The updated script is now available for download as version 0.2 on GitHub at https://github.com/terencejackson8000/encrypt_decrypt/releases. I hope these improvements will help you update your own script and make it more secure.

I have added some enhancements to this script to make it more secure like:

1. Securely handling the strings
2. Securely handling the password with a prompt rather than a parameter

The script now looks like this:

#!/usr/bin/env bash

# Prompt user to enter password
read -s -p "Enter password: " password
echo

# Get the parameters of the script and assign them
while getopts m:s: flag; do
    case "${flag}" in
        m) mechanism="${OPTARG}" ;;
        s) string="${OPTARG}" ;;
        *) exit 1 ;;
    esac
done

# Check if all parameters are set, if not show an error message and exit the script
if [ -z "$mechanism" ] || [ -z "$string" ]; then
    echo "You need to set all variables to run the script: -m enc for encryption or dec for decryption, -s The string to encrypt/decrypt"
    exit 1
fi

# Check if mechanism is valid
if [[ "$mechanism" != "enc" && "$mechanism" != "dec" ]]; then
    echo "Mechanism (-m) must be enc for encryption or dec for decryption"
    exit 1
fi

if [ "$mechanism" == "enc" ]; then
    if [ -d "$string" ]; then
        # Get the last folder of the provided path
        dir="$(basename "$string")"
        # Compress the folder
        tar -czvf "${dir}.tar.gz" "$string"
        # Encrypt the tar file
        openssl enc -e -a -in "${dir}.tar.gz" -aes-256-cbc -salt -pass "pass:$password" -pbkdf2 -base64 -out "${dir}.enc"
        # Delete the tar file
        rm "${dir}.tar.gz"
        echo "Folder encryption done"
        elif [ -f "$string" ]; then
        openssl enc -e -a -in "$string" -aes-256-cbc -salt -pass "pass:$password" -pbkdf2 -base64 -out "${string}.enc"
        echo "File encryption done"
    else
        echo "$string" | openssl enc -base64 -e -aes-256-cbc -salt -pass "pass:$password" -pbkdf2
    fi
fi

if [ "$mechanism" == "dec" ]; then
    if [ -f "$string" ]; then
        new_str="$(echo "$string" | sed 's/.enc//')"
        openssl enc -d -a -in "$string" -aes-256-cbc -salt -pass "pass:$password" -pbkdf2 -base64 -out "$new_str"
        echo "File decryption done"
    else
        echo "$string" | openssl enc -base64 -e -aes-256-cbc -salt -pass "pass:$password" -pbkdf2
    fi
fi

By using Openssl, you can be confident that your sensitive data is protected. With this updated script, you can enjoy even greater security for your string encryption and decryption needs.