gpg: [don't know]: invalid packet (ctb=00)

[Ángel]

On 2021-03-03 at 09:17 +0100, Charles Moulliard via Gnupg-users wrote:
> As the file was present on the filesystem, I suspect another error
> then. Anyway, GPG should report a more user friendly message
> explaining what we should investigate to fix it.

Of course the file is there. The problem is with its contents.
Run
  gpg --list-packets secring.gpg

that should begin with
# off=0 ctb=95 tag=5 hlen=3 plen=...
:secret key packet:
...

but it will probably show you
 gpg: [don't know]: invalid packet (ctb=00)

either due to nul bytes at the beginning, or after some valid pgp
packets.


Cheers