* aboietf(_at_)redtenbacher(_dot_)de wrote:
(1) Are such keys a security problem?
In general: Yes. In this particular case: No.
(2) Is such a key conforming to the OpenPGP spec (or at least
interoperable with a conforming OpenPGP product)?
There are 2.6.x versions of PGP generating keys without a self signature.
So they are introduced and common, despite considered obsolet.
(3) Which OpenPGP products support such unusual public keys?
There is a strong movement to require the self signature. This is currently
work in progress on the whole key space.