[Cryptography] OpenPGP and trust

Dave Horsfall dave at horsfall.org
Sun Mar 30 01:56:38 EDT 2014

On Sat, 29 Mar 2014, Watson Ladd wrote:

[ Encryption over Amateur Radio ]

> > Naturally I changed the key every so often, because the idiots 
> > regarded it as a challenge to decrypt my commands (I'd quickly learned 
> > to avoid replay attacks by using some sort of a rolling-key scheme), 
> > but strong crypto was, and still is, a definite no-no.
> Aren't MACs okay? I believe the 2003 ARRL handbook explains that each 
> command to an OSCAR is suffixed with an authentication code to prevent 
> mischief.

Can't remember (well, you show me wet-ware that's still working after 60+ 
years) but yeah, encryption is allowed for satellite commands and the 
like; we merely had to inform the powers-that-be of our scheme.

I don't think that anyone has hijacked an Amateur satellite yet, but I do 
recall that, err, pr0n broadcast over a commercial bird...  No doubt the 
Mums and Dads were desperately trying to cover the eyes of their little 
ones, whilst desperately searching for the off switch :-)

Moral: Always expect the unexpected, then you'll never be surprised.

-- Dave, with a seriously warped sense of humour

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