[Fsfe-ie] description of Tivoisation - comments sought

Ciaran O'Riordan ciaran at fsfe.org
Fri Dec 15 20:08:33 CET 2006

David O'Callaghan <david.ocallaghan at cs.tcd.ie> writes:
> I may be wrong but I assume that at least some Tivoisation schemes use
> cryptographic digital signatures.

I think all do, but if a lawyer wants an explanation, then I'm thinking that
"digital fingerprints" is an easier idea to understand than encryption keys.

Tivoisation could be done with watermarking-like fingerprints, or it could
be done with encrpytion keys.  In practice, it's probably always done with
encryption keys, but for thinking about the licence and how to block
tivoisation, I think (and I'm open to correction here) the two
implementation are the same.

Maybe instead of saying "insert the fingerprint into the software", I should
say "hide the fingerprint in the software" - to avoid the confusion you
mention where it looks easy to spoof.

> it might be best to verify
> them with others more familiar with, say, the actual Tivo devices.

I don't know anyone I can do that checking with, but it's ok to just think
of the range of ways it could work and assume Tivo uses one of those.

Ciarán O'Riordan __________________ \ http://fsfeurope.org/projects/gplv3
http://ciaran.compsoc.com/ _________ \  GPLv3 and other work supported by
http://fsfe.org/fellows/ciaran/weblog \   Fellowship: http://www.fsfe.org

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