Comparison of RSA vs elliptical keys

[Ángel]

On 2020-05-16 at 22:49 +0200, Stefan Claas wrote:
> out of curiosity, you signed the reply with two sub keys, but
> what makes the signature so large, the hash algo used? I must
> admit I have never seen such a large signature before.

It is quite large, indeed. This Radix 64 block of 12375 bytes contains
two signatures, of 3857 and 5225 bytes respectively. The first one EdDSA
(22) and the second a normal RSA one.

In both cases, most of the signature space is taken by a hashed
subpacket of type 38. This value is not assigned, but looking at
https://git.gnupg.org/cgi-bin/gitweb.cgi?p=gnupg.git;a=blob;f=common/openpgpdefs.h#l123
it is used to store the whole key used.


Cheers