I would like to share some interesting info of Kasumi implementation on Third
Generation Phones.
http://www.etsi.org/WebSite/OurServices/Algorithms/3gppalgorithms.aspx
Check DOCUMENT 2.
The new attack speed up the decoding process, it is a practical attack (compare
to previous 2005 attack).
(COPY/PASTE from http://en.allexperts.com/e/k/ka/kasumi.htm)
KASUMIIn cryptography, KASUMI, also termed A5/3, is a block cipher used in the
confidentiality (f8) and integrity algorithms (f9) for 3GPP mobile
communications. KASUMI was designed by the Security Algorithms Group of Experts
(SAGE), part of the European standards body ETSI. Rather than invent a cipher
from scratch, an existing algorithm, MISTY1, was selected by SAGE and slightly
optimised for implementation in hardware. Hence, both MISTY1 and KASUMI are
very similar — kasumi (霞) is the Japanese word for "misty" — and the
cryptanalysis of one is likely to be readily adaptable to the other.
KASUMI has a block size of 64 bits and a key size of 128 bits. It is a Feistel
cipher with eight rounds, and like MISTY1 and MISTY2, it has a recursive
structure, with subcomponents also having a Feistel-like form.
In 2001, an impossible differential attack on six rounds of KASUMI was
presented by Kühn (2001).
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. 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 not a practical attack, it
invalidates some proofs about the security of the 3GPP protocols that
had relied on the presumed strength of KASUMI.
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