The Hitchhiker's Guide to PGP

PGP (Pretty Good Privacy) is an encryption software that is used to protect data privacy and secure communication between two parties. It allows its users to securely exchange data and digital transmissions, by providing encryption and decryption tools.

PGP encryption

To provide encryption and decryption, PGP uses public key cryptography. Public key cryptography is an asymmetric encryption scheme that uses two different keys, the public key that encrypts data and the private key for decryption.
You are free to share your public key with anyone while keeping your private key secret. Anyone with your public key can use it to encrypt information that only you can decrypt using your private key.
To use PGP encryption, you first need to generate a public and private key pair using a PGP software, such as Kleopatra. You can then share your public key with others, who can then use it to encrypt data they want to send to you.
Here's how PGP message encryption works:

Key generation

A user generates a pair of keys, a public key, and a private key. The public key is shared with others while the private key is kept secret.

Encryption

To send an encrypted message, the sender uses the recipient's public key to encrypt the message. This ensures that only the intended recipient can decrypt the message.

Decryption

The recipient then uses their private key to decrypt the encrypted message.

Signing

For additional security, the sender can use their private key to add a digital signature to the message. The signature acts as proof that the message was written and sent by the key owner.

Verification

On receiving a signed message, the recipient can use the sender's public key to verify the digital signature of a message. A valid signature proves that the message was sent by the sender and has not been changed. The slightest change in the original message, even by just one character will cause the verification process to fail.
Here's a step-by-step guide to how you can do all this with Kleopatra:

Download and Install Kleopatra

Go here and download Gpg4win (GNU Privacy Guard for Windows) installer. Kleopatra, a certificate manager for OpenPGP, is one of the software contained in Gpg4win.
For Linux users, get Kleopatra here.

Install Kleopatra

Install the program and run it.

Generate a PGP Key Pair

Once the installation finishes, Click on “New Key Pair.”

New Key Pair Generation

You will then have the option to set a name to be associated with your PGP public key. You can also enter your email address and protect your key with a passphrase. The passphrase will make sure you're the only one with access to your private key.

Enter name, email address, and passphrase

Click OK on the success popup.

Key successfully created

Next, double-click on the certificate you just created and then click on "Export."

Export your public key

This will open a popup with your public key. You can copy it, save it and share it with other people.

The public key

You can delete the lines that begin with "comment" if you do not wish to share the information with others.

Import Public Keys

To encrypt messages you send to others, you will need to import their PGP public keys.
Copy the public key you want to import and paste it into the Notepad.

Begin the import process

Next, click on Tools, then Clipboard followed by Certificate Import.

Certify the import

On the popup, click on Certify. The information displayed on the popup that follows can help you verify that you are importing the correct public key.
Click Certify, followed by OK on the next popup.

Key successfully imported

Encrypt a Message

Copy the plain text message you want to import and paste it into the Notepad.

Begin encryption

Next, click on Tools, then Clipboard followed by Encrypt. On the popup, click on Add Recipient.
Then select the public key you want to encrypt the message with and click on OK.
[img]Recipient added[/img]
Click on Next to start the encryption process. Click on OK after the encryption completes.

Encryption completed

The encrypted message is saved in your clipboard, you should paste and send it to the intended recipient as it is.

Decrypt a Message

To decrypt a message encrypted with your PGP public key, paste the whole message as it is on the Notepad. You should then click on “Decrypt/Verify Notepad.”

Decrypt a message encrypted with your public key

The decryption process will only be successful if the message was encrypted with your public key.

Sign a Message

Paste the message you want to sign on the Notepad. Then click on recipients. Unchecking the “Encrypt for me” and “Encrypt for others” checkboxes, will result in an unencrypted message.

Sign a message with your keys

Next, click on Sign Notepad. The signed message will be on the Notepad once the signing succeeds.

Message signed

Verify a Signed Message

To verify a signed message you will need to have imported the sender's public key.
Paste the message into the Notepad.

Verify signed message

Click on the “Decrypt/Verify Notepad” tab to verify the message.

Successfully verified signature

The message will be successfully verified if the signature is valid.
Basically, PGP encryption secures communications by:

• Preventing the modification and interception of data during transfer.
• Ensuring the transferred data is protected from unauthorized access.
• Allowing recipients to verify the authenticity of senders.

Keeping private keys secure is crucial in ensuring the integrity of the encryption process is preserved. Remember to back up your keys and secure the backups.