Introduction

Sensitive file protection is more crucial in the digital terrain of today than it was years ago. Encryption guarantees that only authorised users may access your data whether you are protecting personal or corporate records. Implementing the Pretty Good Privacy (PGP) encryption standard, GNU Privacy Guard (GPG) is one of the most potent tools available for file encryption. This post will lead you through how to efficiently use GPG to encrypt and decrypt Linux files.

GPG Encryption is what?

Free and open-source, GPG (GNU Privacy Guard) encryption program lets users sign, encrypt, and validate messages and data. Its very safe for both personal and professional use since it employs both symmetric and asymmetric encryption.

Symmetric encryption locks and decodes data using a single key.

Using a pair of keys—public and private—asymmetric encryption encrypts and decodes.

Sensitive data, documents, and emails are all routinely sent using GPG.

Putting GPG on Linux

Make sure GPG is installed on your Linux machine before encrypting documents. GPG pre-installed is standard for most Linux distributions. Running will allow you to see whether it is installed.

gpg –version

Should GPG not already be installed, you may do so with:

Debian/Ubuntu:

sudo apt install gnupg && sudo apt update

CentOS/RHEL:

sudo yum install gnupg

Arch Linux:

sudo pacman -S gnupg

File Encryption Using GPG: Methods

GPG encryption guarantees that only those with the proper decryption key may access the content of a file.

Symmetric encryption, or encrypting a file with a password

Run the following to encrypt a file using a password:

gpg –symmetric –cipher-algo AES256 file.txt

The –symmetric flag indicates to GPG to employ symmetric encryption.

Advanced Encryption Standard with a 256-bit key is AES256.

To lock the file, you will be requested to enter a password.

The encrypted file will be saved as file.txt.gpg.

Public-Key Encrypting a File

Only a designated recipient—who possesses the private key—can decode the file using public-key encryption.

Step 1: Create a GPG Key Pair (if you do not already have one)

gpg –full-generate-key

Choose default option RSA encryption.

Select a key size: strong encryption calls for 4096 bits.

Either set an expiration date or keep it free from restrictions.

Add your name and email address.

Give your key a strong passphrase.

Your present GPG keys can be listed with:

gpg –list-keys

Step 2: Export and share your public key

gpg –export -a “recipient@example.com” > recipient_public_key.asc

Show the designated recipient this public key.

Step 3: Encrypt a file with the public key

gpg –encrypt –recipient recipient@example.com file.txt

Only the receiver will be able to decode this encrypted file (file.txt.gpg) with their private key.

How to decrypt a file encrypted with GPG?

1. Deciphering a file encrypted with symmetric encryption

If you encrypted a file using a password, decrypt it with:

gpg –decrypt file.txt.gpg > file.txt

You will be asked to input the password you used for encryption.

2. Decrypting a file encrypted with a public key

If a file was encrypted using a public key, the recipient must use their own private key to decrypt it:

gpg –decrypt file.txt.gpg > file.txt

The passphrase for the private key will be prompted.

Guidelines for Making Use of GPG Encryption

• Make sure your private key is protected with a strong, distinctive passphrase.
• Keep your private key secret; never distribute it to anyone.
• Verify the validity of an encrypted file by checking the sender’s GPG signature.
• If a private key is compromised, promptly revoke it using Key Revocation:

gpg –gen-revoke keyID > revoke.asc
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Q&Rs

1. Apart from PGP, what distinguishes GPG?

Pretty Good Privacy (PGP) encryption standard is an open-source implementation by GPG. While both provide digital signatures and encryption, GPG is free and extensively supported on Linux.

2. Can I encrypt several files concurrently?

Yes, you can use tar to encrypt multiple files together:

tar -czf files.tar.gz file1.txt file2.txt | gpg –symmetric –cipher-algo AES256 –output files.tar.gz.gpg

3. How can I distribute my public key among others?

Share your public key by email or a public key server:

gpg –export -a “Your_Email@example.com” > public-key.asc

4. Importance of trust in public keys?

Import the key:

gpg –import public-key.asc

Sign it to indicate trust:

gpg –sign-key keyID

5. How can I remove an unneeded GPG key?

Deleting a public key:

gpg –delete-key keyID

To erase a private key:

gpg –delete-secret-key keyID

Conclusion

One of the best strategies for Linux file security and protection of private data is GPG encryption. GPG offers a strong solution for data security regardless of your preference for public-key or password-based encryption. Following the advice in this guide will help you to keep your data free from unauthorized access.

Visit the official GPG Documentation for additional reading.