[messaging] Value of deniability

Jacob Appelbaum jacob at appelbaum.net
Wed Dec 10 11:57:13 PST 2014

On 12/10/14, Eleanor Saitta <ella at dymaxion.org> wrote:
> Hash: SHA256
> On 2014.12.10 13.56, Mike Hearn wrote:
>> I would like to hear opinions on the value of deniability in OTR
>> like protocols.
>> From a privacy perspective the rationale is fairly clear.
> Has anyone ever seen a case where cryptographic deniability was
> accepted by a judge?  As far as I can tell, its legal value is a
> fiction from the cryptographic community.

Yes, I think so. The lack of signatures ensures that a text log is
just that - a text file without cryptographic assurances. It is
subject to tampering. If I recall correctly, this issue came up a bit
in Anakata's recent trials.

Furthermore, the inverse is accepted routinely - digital signature
laws in some US states. Washington State in the United States seems to
be an example. If you have a PGP signed email, I'd expect some binding
laws to apply for statements made in the signed portion of the text.
Without a signature, I don't it will fall under the same digital
signature statutes.

Repudiation and non-Repudiation are real properties that they have
contextual value.

All the best,

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