Turing (cipher)

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Turing is a stream cipher developed by Gregory G. Rose and Philip Hawkes at Qualcomm for CDMA.[1]

Turing generates 160 bits of output in each round by applying a non-linear filter to the internal state of an LFSR. It is named after Alan Turing.[citation needed] It was developed based on the SOBER cipher introduced by Rose in 1998.[2] This is evident in its major component, the Linear Feedback Shift Register (LFSR), which is the same technology found in the family of SOBER machines.[3] Turing, however, is distinguished from its predecessors by the way it produces five words (five times more) of output for every internal update.[2] It also provides up to 256-bit key strength and is designed to be fast in software,[3] achieving around 5.5 cycles/byte on some x86 processors.

There are experts who found that the Turing stream cipher has a number of weaknesses when faced with chosen IV attacks.[4] For instance, its key scheduling algorithm has the same secret key for different initialization vectors and this is found to lower the system's security.[4]

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  1. ^ Gregory G. Rose and Philip Hawkes, Turing: A Fast Stream Cipher, Fast Software Encryption 2003, pp. 290–306 (PDF).
  2. ^ a b Robshaw, Matthew; Billet, Olivier (2008). New Stream Cipher Designs: The ESTREAM Finalists. Berlin: Springer Science & Business Media. p. 58. ISBN 978-3540683506.
  3. ^ a b Johansson, Thomas (2003). Fast Software Encryption: 10th International Workshop, FSE 2003, LUND, Sweden, February 24-26, 2003, Revised Papers. Berlin: Springer Science & Business Media. p. 290. ISBN 3540204490.
  4. ^ a b Matsui, Mitsuru; Zuccherato, Robert (2004). Selected Areas in Cryptography: 10th Annual International Workshop, SAC 2003, Ottawa, Canada, August 14-15, 2003, Revised Papers. Berlin: Springer Science & Business Media. p. 205. ISBN 3540213708.


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