How OpenPGP Encrypts Your Data

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How OpenPGP Encrypts Your Data

OpenPGP is the most widely adopted standard for encrypted communication. It powers tools like FlowCrypt and ensures that your emails, files, and messages stay private, even if intercepted. But how does it actually work?

This post breaks down the encryption process in simple terms.

The Basics of Encryption

At its core, encryption transforms readable data (plaintext) into an unreadable format (ciphertext). Only someone with the right key can turn it back into readable form. OpenPGP uses a hybrid encryption model, combining the speed of symmetric encryption with the security of asymmetric encryption.

  • Symmetric Encryption: Uses one key to both encrypt and decrypt data. Fast, but the key must be shared securely.
  • Asymmetric Encryption: Uses a key pair, one public, one private. The public key encrypts, and the private key decrypts.

How OpenPGP Uses Both

When you send an encrypted message with OpenPGP:

  1. A random session key is generated.
  2. Your message is encrypted with this session key using symmetric encryption (fast and efficient).
  3. The session key itself is then encrypted with the recipient’s public key using asymmetric encryption.
  4. Both the encrypted message and encrypted session key are sent to the recipient.

When the recipient gets the message:

  • Their private key decrypts the session key.
  • That session key then decrypts the message.

This two-layered process combines performance with strong security.

Why It Matters

  • Confidentiality: Only the intended recipient can decrypt the message.
  • Integrity: Digital signatures ensure the message hasn’t been altered.
  • Authentication: The recipient can verify who the sender really is.

This makes OpenPGP a trusted standard for securing sensitive communications worldwide.

Learn More with FlowCrypt

FlowCrypt brings OpenPGP encryption to Gmail in an easy-to-use way so your team can benefit from proven encryption without complex setups. If you want to see how FlowCrypt helps organizations use OpenPGP, explore the FlowCrypt Email Encryption overview.

If you’re also interested in Google Workspace Client-side Encryption (CSE), check out our FlowCrypt Workspace Key Manager.