Blog | G5 Cyber Security

GPG Key: Too Many User IDs?

G5 Cyber Security

TL;DR

Having lots of user IDs (UIDs) on your GPG key isn’t inherently a security risk, but it can make things more complicated and potentially increase the chance of accidental misuse. It’s generally best to keep the number of UIDs reasonable – only those you actively use.

Understanding User IDs

A GPG key can have multiple user IDs associated with it. Each UID represents a different name, email address, or other identifier that can be used to sign and encrypt messages. Think of it like having several aliases for the same key. The primary UID is the one you use most often.

Why Too Many UIDs Can Be Problematic

  1. Revocation Complications: If a UID gets compromised, you need to revoke *that specific* UID. With many UIDs, this becomes tedious and error-prone. You might accidentally revoke the wrong one!
  2. Key Confusion: When listing keys or importing them, a key with dozens of UIDs can be harder to identify correctly.
  3. Accidental Use: You (or someone else) could inadvertently sign something with the wrong UID, leading to trust issues.
  4. Subkey Management: While not directly caused by many UIDs, complex key setups often involve subkeys. More UIDs can add to this complexity.

How to Check Your Current User IDs

You can list the user IDs associated with your key using the following command:

gpg --list-keys --with-colons | grep uid

This will output a list of UIDs, showing their fingerprint and email address. For example:

gpg: key 1234567890ABCDEF: public key 'Your Name <your.email@example.com>'
gpg: key 1234567890ABCDEF: public key 'Another Name <another.email@example.com>'

Reducing the Number of User IDs

  1. Identify Unused UIDs: Go through your list (from step 2) and identify any user IDs you no longer use or are unlikely to use in the future.
  2. Remove Old/Unused UIDs: You can remove a UID from your key using the following process:
    • Edit your key: 
      gpg --edit-key 1234567890ABCDEF

      (replace with your actual key ID)

    • Select the key to edit: Type ‘key 1’ if it’s the first key listed, etc.
    • Remove the UID: Type ‘uid ‘ (the number shown in the output of step 2). You will be prompted for confirmation.
    • Save changes and exit: Type ‘save’, then ‘quit’.
  3. Consider Subkeys: If you need different keys for different purposes, consider using subkeys instead of adding more UIDs to your primary key. This keeps the main key secure and simplifies management.

Best Practices

Exit mobile version