[OTR-users] OTR - AKE v2

[CLAY SHENTRUP]

On 3/19/06, Ian Goldberg <ian at cypherpunks.ca> wrote:
>
>   1: A -> B: H(g^x), E(r, g^x), where r is a random symmetric key
>   2: B -> A: g^y
>   3: A -> B: r, "A", Sign...
>   4: ...
>
> Alice sends the value of g^x in the first message, but encrypts it with a
> random key.  She then reveals the key in message 3, which is equivalent
> to revealing the value of g^x.  The 128-bit r is much smaller than the
> 1500+ bit Diffie-Hellman exponent g^x, and this way message 3 *just*
> squeaks by under the message size limits.  Welcome to real-world
> security protocol engineering!


You are a kinder, more tolerant man than I.  I have to admit, I'd be
ignoring any protocol but Jabber.

CLAY
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