[OTR-dev] Extra symmetric key in Java implementations
Ian Goldberg
ian at cypherpunks.ca
Thu Aug 16 08:30:27 EDT 2012
On Wed, Aug 15, 2012 at 11:44:19PM -0700, Tommy C. Li wrote:
> Hi,
>
> I wasn't able to find the referenced
>
> otrl_message_symkey
>
> function in the C library either. Has it been removed since 2008?
Look in version 4 of libotr; that's where it is.
> Is there any difference in the "extra" symmetric key compared to just generating 256 random bits and sending it to the counterparty inside a TLV?
Yes. In the "extra" symkey model, the value is derived from the current
DH parameters. That way, both sides are assured it's fresh.
- Ian
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