[Cryptography] RSA equivalent key length/strength

Bill Frantz frantz at pwpconsult.com
Wed Sep 25 18:55:10 EDT 2013

On 9/24/13 at 4:58 PM, hallam at gmail.com (Phillip Hallam-Baker) wrote:

>And the problem appears to be compounded by dofus legacy implementations
>that don't support PFS greater than 1024 bits. This comes from a
>misunderstanding that DH keysizes only need to be half the RSA length.
>So to go above 1024 bits PFS we have to either
>1) Wait for all the servers to upgrade (i.e. never do it because the won't
>2) Introduce a new cipher suite ID for 'yes we really do PFS at 2048 bits
>or above'.
>I suggest (2)

Agreed, however eventually we will want to do (3):

(3) Make insecure obsolete servers show as insecure in the 
user's UI or refuse to communicate with them. Embedded systems 
are the Achilles Heel of this suggestion. The only way to 
upgrade them is to replace them, which might be too costly.

Cheers - Bill

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