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What is PGP Encryption?

Have you ever thought about how submarines talk to each other safely? These underwater boats need to send messages to far-away naval bases without being found. They use special codes to keep their messages safe from outliers. 

Keeping information safe is important not just for submarines but also when we use the online services. Online, keeping our personal information private is really important. Encryption is like a shield that keeps our data safe and only lets certain people see it. Enter Pretty good privacy (PGP). It's a popular way to put messages in a code and then decode them. PGP is easy to use but also very safe, making it a key part of keeping our online lives private and secure.

What is PGP in Information Security?

PGP, or Pretty Good Privacy, is an encryption program widely used for sending encrypted emails and encrypting sensitive files. Invented in 1991 by Phil Zimmermann, PGP has become a standard for secure email communication.

What is PGP encryption?

PGP's popularity stems from two main factors. Initially, it was available as freeware, quickly gaining a user base that sought enhanced email security. Additionally, PGP employs a mix of symmetric and public-key encryption, enabling users who have never met to exchange encrypted messages without needing to share private keys.

More than just email security, PGP is a versatile tool for data encryption, offering authentication and cryptographic privacy for various types of data transfers.

PGP vs. OpenPGP

PGP was originally created for secure digital communication, which included use on Bulletin Board Systems (BBS) - a type of computerized messaging system popular before the mid-nineties. As technology evolved, PGP went through several ownership changes, eventually being acquired by Symantec in 2010.

A bulletin board system (BBS) is a computer or an application dedicated to the sharing or exchange of messages or other files on a network.

OpenPGP, also known as Open-source PGP, was developed collaboratively to circumvent patent restrictions limiting PGP's use. Now an Internet Engineering Task Force (IETF) approved standard, OpenPGP allows any company to create and sell PGP-compatible products.

How Does PGP Work?

PGP keeps digital assets like text messages, emails, files, and even disk partitions secure. But the question how pops in everyone’s minds, here is how PGP secures data:

  1. Key System: PGP uses two types of keys - a public key that everyone can see, and a private key that only the user knows. To send a secure message, you encrypt it with the recipient's public key. They then use their private key to decrypt it.
  1. Efficient Encryption: Encrypting large messages with public key encryption alone can be slow. So, PGP first encrypts the message with a faster, symmetric key. Then, it encrypts that symmetric key with the recipient's public key. Both the encrypted message and the encrypted symmetric key are sent to the recipient.
  1. Digital Signatures: For digital signatures, PGP creates a unique code (hash) from the message and encrypts it with the sender's private key. The recipient can use the sender’s public key to verify the hash and confirm the message’s authenticity.
How does PGP encryption work?
PGP Encryption Process

Using PGP for email

  • Get a PGP Program: Some email applications have PGP built-in, or you might need a separate tool.
  • Public Key: Share your public key with others so they can send you encrypted messages.
  • Private Key: Keep this key secret. It decrypts messages sent to you and signs your outgoing messages.

Sending a PGP-Encrypted Email

  • Encrypt: Use the recipient’s public key to encrypt your message.
  • Send: The encrypted message travels securely to the recipient.
  • Decrypt: The recipient uses their private key to decrypt the message.

For extra security, some systems use a unique session key for each message, which is encrypted with the recipient's public key. In highly secure scenarios, a phone call might be used to verify identities and keys.

PGP Use Cases

PGP is primarily used for two reasons: Encryption and Authentication.

  • Encryption: PGP allows users to encrypt sensitive data, such as files, emails, or messages, ensuring that only the intended recipient, who has the secret key, can decrypt and access the information.
  • Authentication: Through digital signing, PGP enables the authentication of messages, files, or emails, whether they are encrypted or not. The recipient can use the signer's public key to verify the authenticity of the digital signature.

PGP software provides various functions, including creating and revoking public key pairs, managing keys, encrypting and decrypting messages, digitally signing and authenticating signatures, and more. Different OpenPGP implementations offer similar functionalities but may vary slightly in their processes.

Specifically, PGP is often used for:

Digital Signatures 

These confirm the sender's identity and ensure that a message hasn't been altered. PGP adds a digital signature to messages, which can be authenticated by the recipient using the sender's public key.

Email Encryption

For secure communication via email, PGP requires an exchange of public keys between sender and recipient. This allows encrypted messages to be sent and decrypted by the intended recipient.

File Encryption

PGP also secures files, either in transit or at rest. It offers various functions compatible with different operating systems and software, including encrypting individual files, multiple documents, or entire folder trees.

Disadvantages of PGP Encryption

PGP is a quick-to-implement and cost-effective encryption method. However, it has some drawbacks:

  • The Administration is difficult: The different versions of PGP complicate the administration.
  • Compatibility issues: Both the sender and the receiver must have compatible versions of PGP. For example, if you encrypt an email by using PGP with one of the encryption techniques, the receiver has a different version of PGP which cannot read the data.
  • Complexity: PGP is a complex technique. Other security schemes use symmetric encryption that uses one key or asymmetric encryption that uses two different keys. PGP uses a hybrid approach that implements symmetric encryption with two keys. PGP is more complex, and it is less familiar than the traditional symmetric or asymmetric methods.
  • No Recovery: Computer administrators face the problem of losing their passwords. In such situations, an administrator should use a special program to retrieve passwords. For example, a technician has physical access to a PC which can be used to retrieve a password. However, PGP does not offer such a special program for recovery; encryption methods are very strong so, it does not retrieve forgotten passwords resulting in lost messages or lost files.

Is PGP Encryption Safe?

PGP encryption is renowned for its high security, making it a popular choice in industries handling sensitive information, such as healthcare and finance. PGP's effectiveness hinges on correct and secure usage by individuals and organizations. The encryption method employs algorithms that are currently among the most secure available, making it one of the strongest ways to protect data, including in cloud systems.

While no encryption method can guarantee absolute immunity against all forms of cyber attacks, using PGP to protect data significantly increases the difficulty for unauthorized parties, such as hackers, to access it. However, the overall security also depends on rigorous key management and adherence to best encryption practices.


What is a PGP Used for?

PGP (Pretty Good Privacy) is primarily used for securing emails through encryption and authenticating messages with digital signatures. It also plays a crucial role in file encryption, ensuring data confidentiality and integrity.

What is the Algorithm for PGP?

PGP employs a hybrid cryptosystem combining symmetric-key and public-key encryption. A unique session key encrypts the message, and the recipient's public key encrypts this session key, ensuring secure key exchange and message encryption.

Why is PGP still Used?

PGP remains popular due to its robust security, being nearly unbreakable. It's especially valued for securing data in cloud environments, making it a preferred choice for protecting sensitive information against various cyber threats.

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