Turing (cipher)

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.^[1] 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]

See also

• SOBER-128
• Helix

References

1. Gregory G. Rose and Philip Hawkes, Turing: A Fast Stream Cipher, Fast Software Encryption 2003, pp. 290–306 (PDF).
2. Robshaw, Matthew; Billet, Olivier (2008). New Stream Cipher Designs: The ESTREAM Finalists. Berlin: Springer Science & Business Media. p. 58. ISBN 978-3540683506.
3. 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. 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.

Bibliography

• Antoine Joux and Frédéric Muller, A Chosen IV Attack Against Turing, Selected Areas in Cryptography 2003, pp. 194–207 (PDF).

External links

• Optimized Java implementation of Turing algorithm
• Java Implementation of Turing Algorithm
• Turing: a Fast Stream Cipher
• Slides and C reference implementation at Qualcomm