OpenPGP user IDs as defined in OpenPGP 4880, OpenPGP, 5.11. User ID Packet (Tag 13) are formed by arbitrary strings, "Real Name (Comment) " is not more than a convention. Following the specifications, it even may be the empty string.
5.11. User ID Packet (Tag 13)
A User ID packet consists of UTF-8 text that is intended to represent
the name and email address of the key holder. By convention, it
includes an RFC 2822 [RFC2822] mail name-addr, but there are no
restrictions on its content. The packet length in the header
specifies the length of the User ID.
GnuPG (at least in version 2.1, which I used to verify this statement) does not enforce a name, either -- just omit any content. In fact, GnuPG actually seems to support empty-string user IDs!
gpg> adduid
Real name:
Email address: mail@example.org
Comment:
You selected this USER-ID:
"mail@example.org"
Change (N)ame, (C)omment, (E)mail or (O)kay/(Q)uit?
Not all versions of GnuPG allow free-form user IDs by default and require --allow-freeform-uid
. From man gpg
:
--allow-freeform-uid
Disable all checks on the form of the user ID while generating a new one. This option should only be used in very special environments as it does not ensure the de-facto
standard format of user IDs.
Do you want to remove the name from an existing key or create a new one without it? Technically, this is no problem at all: The PGP key format contains just a UID field which is not required to abide by any particular format (such as the usual "Real Name email@address.tld").
– None – 2017-08-13T18:04:38.250