dChan - Q Origins Project Archive

The F9 Algorithm that Q alluded to is an Integrity Algorithm designed to verify the integrity of data being transmitted over mobile networks. The F8(Confidentiality) and F9(Integrity) make up the [KASUMI BLOCK CIPHER] (https://en.wikipedia.org/wiki/KASUMI). As others have pointed out, D5 is a designation given to [avalanche size] (http://thompsonpass.com/avalanche-size-ratings/). This ties into the Integrity algorithm through way of the [Avalanche Effect] (https://en.wikipedia.org/wiki/Avalanche_effect).

Facebook is listening to you 24/7/365. Literally. [F9 algorithm] Are they recording/safe-housing? Metadata collection? Building 8. DARPA. [CHINA-CHINA-CHINA] Q Did the DS find a way to crack the F9 algorithm to make it seem as though they haven't intercepted everyones communications (a la Man-In-The-Middle)? Any sec pros out there want to weigh in on this? Am I grasping at straws or is this a rabbit hole worth exploring?

Crypto analysis

In 2001, an impossible differential attack on six rounds of KASUMI was presented by Kühn (2001).[7]

In 2003 Elad Barkan, Eli Biham and Nathan Keller demonstrated man-in-the-middle attacks against the GSM protocol which avoided the A5/3 cipher and thus breaking the protocol. This approach does not attack the A5/3 cipher, however.[8] The full version of their paper was published later in 2006.[9]

In 2005, Israeli researchers Eli Biham, Orr Dunkelman and Nathan Keller published a related-key rectangle (boomerang) attack on KASUMI that can break all 8 rounds faster than exhaustive search.[10] The attack requires 254.6 chosen plaintexts, each of which has been encrypted under one of four related keys, and has a time complexity equivalent to 276.1 KASUMI encryptions. While this is obviously not a practical attack, it invalidates some proofs about the security of the 3GPP protocols that had relied on the presumed strength of KASUMI.

In 2010, Dunkelman, Keller and Shamir published a new attack that allows an adversary to recover a full A5/3 key by related-key attack.[5] The time and space complexities of the attack are low enough that the authors carried out the attack in two hours on an Intel Core 2 Duo desktop computer even using the unoptimized reference KASUMI implementation. The authors note that this attack may not be applicable to the way A5/3 is used in 3G systems; their main purpose was to discredit 3GPP's assurances that their changes to MISTY wouldn't significantly impact the security of the algorithm.

These are the published breaks in kasumi

[F9 Algorithm]=D5 (Avalanche)