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Wireshark-users: Re: [Wireshark-users] question about bug 3303

Date: Tue, 7 Sep 2010 12:01:31 +0200 (CEST)
Hi Sake,

This is what I see in my capture that makes me think this might be the
same issue:

216 <timestamp> <srcip> <dstip> TCP   [TCP segment of a reassembled PDU]
217 <timestamp> <srcip> <dstip> TLSv1 Server Hello, Certificate, Server Key Exchange, Server Hello Done

I kind of missed the " Certificate, Server Key Exchange" before. But this means it is a totally different issue. This means the keying material is not created by the client and sent to the server encrypted with it's public key. Instead of that the DH algorithm is used to negotiate keying material. Wireshark is not able to decrypt sessions that used DH to negotiate keys.

You can see this by looking at the chosen cipher in the ServerHello message. It should have DH in the ciphername.

You can circumvent this by restricting the allowed ciphers on either the client or the server.

Indeed, you were right. Thank you!

Just out of interest, will Wireshark support the decryption of sessions that used DH to negotiate keys?