PGP Encryption: A Tutorial and Differences from OpenGP and GnuPG.

Have you ever wondered how you can keep your data and communications safe and private in the online world? How can you prevent attackers, spies, or snoops from accessing or tampering with your information? How can you communicate confidentially with your friends, family, or colleagues without worrying about eavesdropping?

The answer is encryption. Encryption is a technique of transforming data into a scrambled form that only authorized parties can understand. Encryption helps you to protect your privacy and security in the digital world. It allows you to send and receive secret messages, store sensitive information, and prevent unauthorized access or modification.

We have covered this [here](https://www.binaryte.com/blog/the-basics-of- cryptography), and you may find it helpful to understand the basics of encryption. Now, we are going to learn one of the most common and widely used encryption techniques, the PGP encryption. But what exactly is PGP encryption and how does it work? In this article, we will explain the fundamentals of PGP encryption, the difference between PGP, OpenPGP, and GnuPG, and how to use GnuPG for PGP encryption.

What is PGP encryption?

PGP stands for Pretty Good Privacy, and it was invented by Phil Zimmermann in 1991 as a way for people to communicate securely without eavesdropping. Today, PGP encryption is used to encrypt and decrypt text messages, emails, files, and other data. PGP encryption uses a hybrid cryptosystem by combining symmetric-key encryption and asymmetric-key encryption.

How PGP encryption works

PGP encryption is based on a concept called public key cryptography. This means that it uses two different keys to encrypt and decrypt data: a public key and a private key. A public key is a string of characters that can be shared with anyone, while a private key is a secret string of characters that should be kept only by the owner.

The idea is that when you want to send an encrypted message or file to someone, you use their public key to encrypt it. This way, only they can decrypt it with their private key. Likewise, when you receive an encrypted message or file from someone, you use your private key to decrypt it. This way, only you can read it.

To use PGP encryption, you need to generate your own pair of public and private keys. You can do this using a software tool called GnuPG (which we will talk about later). Once you have your keys, you need to exchange them with the people you want to communicate with securely. You can do this by sending them your public key or by publishing it on a public key server or directory. You also need to get their public keys in the same way.

To encrypt a message or file with PGP encryption, you need to use a software tool that supports PGP encryption (such as GnuPG which is based on OpenPGP) and select the recipient’s public key. The tool will then turn the message or file into an encrypted form that can be sent over any channel (such as email or instant messaging). To decrypt a message or file with PGP encryption, you need to use the same tool and select your private key. The tool will then restore the message or file into its original form that can be read.

The difference between PGP, OpenPGP, and GnuPG

You may have noticed that we have used different terms to refer to PGP encryption: PGP, OpenPGP, and GnuPG. What is the difference between them?

PGP is the original encryption software created by Phil Zimmermann in 1991. It is not an open patent and is currently owned by Symantec. In the 1990s, there was a law in the US that restricted the export of cryptographic technology outside the US. This led to a lengthy investigation of Zimmermann for releasing PGP overseas. To avoid legal issues, Zimmermann released the source code of PGP which allowed anyone to create their own versions of encryption software based on PGP.

OpenPGP is an open standard that defines how PGP encryption should work. It was created in 1997 by a group of developers who wanted to make PGP encryption more interoperable and accessible. OpenPGP is defined by RFC4880 (also known as PGP) and specifies the format, algorithms, and procedures for PGP encryption. Anyone can implement OpenPGP in their own software without infringing any patents.

GnuPG is a free implementation of OpenPGP created by Werner Koch in 1999. It is also known as GPG (GNU Privacy Guard) and it is part of the GNU project. GnuPG is a command line tool that allows you to encrypt and decrypt data and communications using OpenPGP. It also features a versatile key management system and access modules for various public key directories. GnuPG is compatible with PGP and other OpenPGP implementations.

How to use GnuPG for PGP encryption

GnuPG is one of the most popular and widely used tools for PGP encryption. It is available for various operating systems, such as Windows, Linux, and Mac OS. You can download GnuPG from its official website. Alternatively, on Windows, you can use a package called Gpg4win, which includes GnuPG and other graphical frontends and plugins. You can download Gpg4win from its official website.

To install GnuPG on Linux, you can use the package manager of your distribution, such as apt, yum, or pacman. For example, on Ubuntu, you can run the following command in a terminal:

sudo apt install gnupg2

To install GnuPG on Mac OS, you can use a package called GPG Suite, which includes GnuPG and other graphical frontends and plugins. You can download GPG Suite from its official website.

Once you have installed GnuPG, you can use it to generate your own pair of public and private keys. To do this, you need to run the following command in a terminal or a command prompt:

gpg --full-generate-key

You will then be asked to choose the type of key, the key size, the expiration date, your name, your email address, and a passphrase. The passphrase is a password that protects your private key from unauthorized access. You should choose a strong and memorable passphrase that you will not forget.

After you have generated your keys, you can view them by running the following command:

gpg --list-keys

You will see something like this:

pub rsa4096 2023-07-06 [SC] [expires: 2025-07-06]
1234567890ABCDEF1234567890ABCDEF12345678
uid           [ultimate] Alice <[email protected]>
sub rsa4096 2023-07-06 [E] [expires: 2025-07-06]

The first line shows your public key, which consists of a key type (rsa), a key size (4096), a creation date (2023-07-06), a usage flag (SC for signing and certifying), an expiration date (2025-07-06), and a key ID (1234567890ABCDEF1234567890ABCDEF12345678). The second line shows your user ID, which consists of your name (Alice) and your email address ([email protected]). The third line shows your subkey, which is used for encryption (E).

To export your public key to a file or to copy it to the clipboard, you can run the following command:

gpg --armor --export [email protected] > alice.pub

gpg --armor --export [email protected] | clip

The --armor option converts your binary key into an ASCII text format that can be easily shared. The --export option specifies the user ID of the key you want to export. The > or | symbols redirect the output to a file or to the clipboard.

To import someone else’s public key from a file or from the clipboard, you can run the following command:

gpg --import bob.pub

clip | gpg --import

The --import option adds the key to your local keyring.

To encrypt a message or file with someone else’s public key, you can run the following command:

gpg --encrypt --recipient [email protected] message.txt

The --encrypt option specifies that you want to encrypt the data. The --recipient option specifies the user ID of the key you want to use for encryption. The last argument is the name of the file you want to encrypt.

This will create an encrypted file called message.txt.gpg that can only be decrypted by Bob with his private key.

To decrypt a message or file with your private key, you can run the following command:

gpg --decrypt message.txt.gpg

The --decrypt option specifies that you want to decrypt the data. You will be asked to enter your passphrase to unlock your private key.

This will restore the original file called message.txt that can be read by you.

Conclusion

We have learned what PGP encryption is and how it works in this article. We have also learned the difference between PGP, OpenPGP, and GnuPG, and how to use GnuPG for PGP encryption.

PGP encryption is a powerful and reliable way to protect your data and communications from unauthorized access or modification. It uses public and private keys to encrypt and decrypt data securely. It is based on an open standard called OpenPGP, which is implemented by various software tools, such as GnuPG.