Hi Matt,
It was a key generated with an old version of ssh-keygen, and then
converted to dropbear format.
The public key length shows 1024 bits with ssh-keygen -l
When I use this private key with dropbear it issued the warning that
the key was < MIN_RSA_KEYLEN
In dropbear the keylen was reported by function mp_count_bits as 1023
I worked around it by adapting the MIN_RSA_KEYLEN to 1023 and did a recompile..
It is not problematic...
Hans
On Thu, Oct 29, 2020 at 1:21 PM Matt Johnston wrote:
>
> Hi Hans,
>
> Sorry I missed replying to this message a while ago.
>
> What program created the key? As far as I can tell the test
> is correct, the top bit might be unset?
>
> Cheers,
> Matt
>
> On Thu, Aug 27, 2020 at 07:36:26AM +0200, Hans Harder wrote:
> > HI,
> >
> > I noticed that I got warnings that the RSA key was too short.
> > Further investigation showed that I was using a 1024 bits RSA key but
> > the mp_count_bits function return 1023 count (probably 0 based)
> >
> > in rsa.c it states:if (mp_count_bits(key->n) < MIN_RSA_KEYLEN)
> >
> > Is this intentional or should I just define the MIN_RSA_KEYLEN as
> > 1023 instead of the 1024 now in sysoptions.h
> >
> > Hans
