In this attack a differential propagates with difficulty for some 20, 40 and up to 64 rounds. We can say that the propagation encounters some “friction”, because the non-linear functions do not always behave as the attacker would like them to behave. Everything looks normal and this is what happens for all block ciphers all …
Continue reading ‘An Anomalous Differential Attack on a Block Cipher’ »
A small ceremony took place on 16 August 2020.
A new documentary tells the story of the discovery of one of the most important cryptography papers of all times. We are talking about an extensive technical report written in German language and entitled “Kurzgefasste Darstellung der Auflösungsmethoden”. For some 80 years it has remained classified, part of the so called Gustave Bertrand WW2 archives. It was …
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In 2004 I have published a paper [Crypto 2004, Santa Barbara] in which I explain the concept of the so called Bi-Linear attack on DES. The old attack was not extremely strong. It is possible to see that two conditions would be necessary for such an attack to somewhat work well in cryptanalysis of DES: There …
Continue reading ‘A Linear Annihilator Property and Strong Biases with Original DES S-boxes’ »
There is abundant literature on the security of Data Encryption Standard (DES or 3DES). Today we have released a new way to attack this cipher, see Section 11 in here. Anyone who reads this paper should immediately see that the high confidence which have developed over decades in research community about our ability to design secure block …
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I have written an elementary tutorial and a first proof of concept about how to backdoor a block cipher in a quite general setting. Potentially it applies to any block cipher. Success is not guaranteed though, see the paper. ADDED 2 JAN 2019: a new paper shows that invariants of higher degree are substantially more powerful. …
Written by UCL student Maxine Emuobosa: Beginners Guide. And here is another one made by UCL student Killian Davitt.
Public donations are sought by Pilsudski Institute in London. The most prominent host of the institute is an extremely rare WW2 Enigma machine. This machine was made in France during WW2 to assist Polish code breakers in their daily code-breaking tasks [done in close collaboration with Bletchley Park, UK]. Only two such machines exist, see here …
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Our trip took place 29 Sept 2017. Some 32 UCL students participated. Students have explored the past in order to find role models for the future. Due to large numbers, we have split into two groups for a guided Bletchley Park tour, and also had assisted at two bombe demonstrations. …
Continue reading ‘UCL InfoSec Visit at Bletchley Park – Friday 29 Sept 2017’ »
When Marc Stevens and a team of researchers from Google have finally found a collision for SHA-1, which we have been expecting for longer than 10 years, somebody who is apparently none of these people, has apparently used it to obtain 2.5 BTC prize created by Peter Todd.