Text Operations

GpgFrontend lets you do four things with text: encrypt it (hide it), decrypt it (read it), sign it (prove it came from you), and verify a signature (check it really did). This page walks through each one.

Before You Start

These tasks use a pair of keys:

• Public key: used to encrypt a message for someone, or to verify their signature.
• Private key: used to decrypt a message sent to you, or to sign your own.

So before you begin, make your own key pair and swap public keys with the people you write to. You encrypt with their public key; they decrypt with their private key.

Encrypt Text

To hide a message so only one person can read it, encrypt it with their public key. Only their private key can open it.

This way:

• The result is short.
• It does not reveal who sent it, which is good when you want to stay anonymous.

Tip

Don’t encrypt with your own public key unless the message is meant for you. Use the recipient’s public key, or only you will be able to read it.

If You Are Asked to Pick a Subkey

Some people have more than one encryption subkey on their key. When that happens, GpgFrontend opens Select Encryption Key(s) and asks which one to use. Expand a key to see its subkeys.

If you have no reason to prefer one, just confirm the selection GpgFrontend offers. This dialog does not appear when there is only one sensible choice.

Sending to a Chat App

A normal encrypted message is a large block of text, and chat apps often break it. GpgFrontend has a second kind of encryption made for exactly that case. See Instant Messaging.

Decrypt Text

To read an encrypted message sent to you, paste or load the ciphertext into GpgFrontend. The tool then:

• Picks the correct private key for you.
• Tells you if it can’t find a matching key.

You don’t need to choose a key by hand. GpgFrontend matches it for you.

Sign Text

To prove a message came from you, sign it with your private key. The text stays readable; signing adds proof, not secrecy.

• It confirms you wrote it.
• Anyone with your public key can check it.

Before you sign, look at the key’s Usage column for an S, which means the key can sign.

Verify a Signature

To check that a signed message is genuine, use the sender’s public key. Paste or load the signed message, and GpgFrontend will:

• Check that the message wasn’t changed.
• Report any mismatch or a missing public key.

Note

If you don’t have the sender’s public key yet, GpgFrontend asks you to import it first.

Safety Tips

• Verify before you trust. Check a signature before you act on a message.
• Share only your public key. Never give out your private key.
• Encrypt and sign together for messages that should be both private and proven.
• Sign only (no encryption) for public documents that need to be trusted but not hidden.