This is our old Q&A Site. Please post any new questions and answers at


I'm trying to build a protocol dissector.

The dissector works just fine, however the problem is the body is encrypted. I already reversed everything and i can retrieve the session key from within the dissector (its hackish but w/e).

However as the key changes, and we can not store extra info somewhere to link a key to a pcap file.

So my question is, is there a way to: A) Store the key somewhere related to pcap file to load the key in the dissector for each pcap file B) Save modified packets to pcap file (its a hell, already tried, but perhaps i looked wrong)

Kind regards, ~Intline9

asked 12 Mar '12, 16:46

Intline9's gravatar image

accept rate: 0%

A) The capture files that Wireshark can read can be in a number of formats; the only format that allows arbitrary information of that sort to be stored in it is pcap-NG format, so that's not a general solution. It also involves registering a new block type for pcap-NG and adding code to support that.

B) Wireshark does not support saving decrypted data out in a conversation (that's why it was hell to try to do so).

Your only general alternative would be to store the extra information in another file, with a preference pointing to that file, or store it in a preference; that's what's used for the other flavors of decryption supported by Wireshark.

permanent link

answered 12 Mar '12, 18:34

Guy%20Harris's gravatar image

Guy Harris ♦♦
accept rate: 19%

After loads of thinkin i thought of another way, we could keep track of packet stream key pairs by getting a checksum of a packet we know that is unique each session and save the checksum with the session key.

Working now to implement that!

(01 Apr '12, 08:59) Intline9
Your answer
toggle preview

Follow this question

By Email:

Once you sign in you will be able to subscribe for any updates here



Answers and Comments

Markdown Basics

  • *italic* or _italic_
  • **bold** or __bold__
  • link:[text]( "title")
  • image?![alt text](/path/img.jpg "title")
  • numbered list: 1. Foo 2. Bar
  • to add a line break simply add two spaces to where you would like the new line to be.
  • basic HTML tags are also supported

Question tags:


question asked: 12 Mar '12, 16:46

question was seen: 2,460 times

last updated: 01 Apr '12, 08:59

p​o​w​e​r​e​d by O​S​Q​A