Mitigating eMail Attacks: GnuPG (en)

This module will guide you step by step in securing your email communications using GnuPG (GNU Privacy Guard) encryption in the Thunderbird email client. GnuPG is a powerful and free encryption tool, while Thunderbird is a popular open-source email client. By combining the two, you can protect sensitive information that you send and receive via email from unauthorized parties.

Module Objectives

• Understand the basic concepts of asymmetric cryptography and GnuPG.
• Create PGP (Pretty Good Privacy) keys and manage the keyring.
• Configure Thunderbird to use GnuPG encryption.
• Send and receive encrypted emails.
• Verify message integrity with digital signatures.

Prerequisites

• A computer with an installed operating system (Windows, macOS, or Linux).
• Thunderbird email client installed.
• A stable internet connection.

Steps

Installing GnuPG and Thunderbird

• GnuPG: Download and install GnuPG from the official website ([1](https://gnupg.org/)). Follow the installation instructions provided.
• Thunderbird: GnuPG is currently a built-in add-on for Thunderbird that facilitates the use of GnuPG.

Creating PGP Keys

• Open the GnuPG application or use the Thunderbird interface to create a PGP key pair.
• Choose an appropriate key length (minimum of 2048 bits) and enter a strong passphrase. This passphrase is crucial for protecting your private key.
• Store your private key in a safe place. The public key can be shared with others who wish to communicate with you securely.

Configuring Thunderbird

• After installing Thunderbird, configure general settings such as keyring location and encryption preferences.
• Import the public keys of others you wish to send encrypted emails to.

Sending Encrypted Emails

• When composing a new email, enable the encryption option in Thunderbird.
• Select the recipient and choose their public key to encrypt the message.
• Write your message and send it.

Receiving and Decrypting Emails

• When receiving an encrypted email, Thunderbird will automatically prompt you for your passphrase to decrypt the message.
• Enter the correct passphrase, and the message will be decrypted.

Verifying Digital Signatures

• In addition to encryption, GnuPG also supports digital signatures to verify the sender's identity.
• Thunderbird will display information about the digital signature when you open a signed email.

Practical Exercises

• Exercise 1: Create your own PGP key pair and share your public key with a friend or family member.
• Exercise 2: Send an encrypted email to a friend or family member who has your public key.
• Exercise 3: Verify the digital signature on an email you received.

Interesting Links

• Forensic: IT
• GnuPG Documentation: [2](https://gnupg.org/documentation/)
• Thunderbird Documentation:
• Basic Concepts of Cryptography: Briefly explain symmetric and asymmetric cryptography, as well as the role of public and private keys in GnuPG.
• Security Best Practices: Provide security tips such as choosing a strong passphrase, protecting your private key, and avoiding phishing.
• Advanced Usage: Explain advanced Thunderbird features like creating digital signatures, file encryption, and keyring management.