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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.
• Asymmetric encryption encrypts and decodes using a pair of keys—public and private.

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.

1. Symmetric encryption (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.
• AES256 is the Advanced Encryption Standard with a 256-bit key.
• You will be requested to enter a password to lock the file.
• The encrypted file will be saved as file.txt.gpg.

2. 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 not already created)

gpg –full-generate-key

• Choose default option RSA encryption.
• Select a key size: 4096 bits for strong encryption.
• Either set an expiration date or keep it free from restrictions.
• Add your name and email address.
• Give your key a strong passphrase.

List your present GPG keys with:

gpg –list-keys

Step 2: Export and Share Public Key

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

• Share this public key with the designated recipient.

Step 3: Encrypt a File with Public Key

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

• Only the receiver will be able to decrypt file.txt.gpg with their private key.

How to Decrypt a File Encrypted with GPG

1. Deciphering a File Encrypted in Symmetric Fashion

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

gpg –decrypt file.txt.gpg > file.txt

You will be asked to input the password used during encryption.

2. Public-Key Decryption of an Encrypted File

If a file was encrypted using a public key, the recipient needs their 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

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

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

1. Apart from PGP, what distinguishes GPG?

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

2. Can I encrypt multiple files at once?

You can use tar to encrypt multiple files:

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

3. How can I share my public key with others?

You can share your public key via 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 crucial key:

gpg –import public-key.asc

Sign it to show trust:

gpg –sign-key keyID

5. How can I remove an unnecessary GPG key?

Deleting a Public Key:

gpg –delete-key keyID

Deleting a Private Key:

gpg –delete-secret-keys 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 keep your data secure from unauthorized access.

Visit the official GPG Documentation for additional reading.