Translations:Concepts/OpenPGP Getting Started/20/en

User IDs are formally just arbitrary strings but expected to consist of a name, an optional comment, and an email address. This structure allows email software to find the suitable key for a recipient address (which most programs require you to confirm for obvious reasons). An OpenPGP public key (more precise: certificate) must have a user ID but can have as many as you like. Thus you can use the same key for several email addresses (which makes sense only if these addresses shall be used at the same security level). Combining addresses has advantages and disadvantages. The main advantage is that you need less keys and thus you and others have less work with certifications. The main disadvantages are that you can revoke user IDs but they keep visible forever and that such a combined key allows to make a trivial connections between different roles of you which you may not want connected: private person, business, other organizations (associations, political parties, whatever). You may want to keep these groups separate. And there are even reasons to keep addresses from the same group separate: reputable addresses (firstname.lastname@example.com), anonymous addresses (heejei7u@example.org), fun addresses (superman17@example.org). It also may be that you have no reason to ever use OpenPGP with certain addresses; such addresses should not be part of a user ID, of course. The decision to add an address to a key and publish that key is forever. But it is easy to add an address later. Thus consider this well before you generate the key. In case of doubt start with fewer addresses.