Skip to main content
SpringerLink
Log in

A5/1

  • Reference work entry
Encyclopedia of Cryptography and Security

  • 2349 Accesses

Related Concepts

Stream Cipher

Definition

A5/1 is the symmetric cipher used for encrypting over- the-air transmissions in the GSM standard. A5/1 is used in most European countries, whereas a weaker cipher, called A5/2, is used in other countries (a description of A5/2 and an attack can be found in [9]).

Background

The description of A5/1 was first kept secret, but its design was reversed engineered in 1999 by Briceno, Golberg, and Wagner.

Theory

A5/1 is a synchronous stream cipher based on linear feedback shift registers (LFSRs). It has a \(64\)-bit secret key.

A GSM conversation is transmitted as a sequence of 228-bit frames (114 bits in each direction) every \(4.6\) millisecond. Each frame is xored with a 228-bit sequence produced by the A5/1 running-key generator. The initial state of this generator depends on the 64-bit secret key, \(K\), which is fixed during the conversation, and on a 22-bit public frame number, \(F\).

Description of the Running-Key Generator

The A5/1 running-key...

This is a preview of subscription content, log in via an institution to check access.

Access this chapter

Log in via an institution
Chapter
USD 29.95
Price excludes VAT (USA)
  • Available as PDF
  • Read on any device
  • Instant download
  • Own it forever
eBook
USD 799.99
Price excludes VAT (USA)
  • Available as EPUB and PDF
  • Read on any device
  • Instant download
  • Own it forever
Hardcover Book
USD 949.99
Price excludes VAT (USA)
  • Durable hardcover edition
  • Dispatched in 3 to 5 business days
  • Free shipping worldwide - see info

Tax calculation will be finalised at checkout

Purchases are for personal use only

Institutional subscriptions

Recommended Reading

  1. Barkan E, Biham E, Keller N (2003) Instant ciphertext-only cryptanalysis of gsm encrypted communication. In: Advances in cryptology – CRYPTO’03. Lecture notes in computer science number, vol 2729. Springer, Heidelberg, pp 600–616

    Google Scholar 

  2. Barkan E, Biham E (2005) Conditional estimators: An effective attack on A5/1. In: Selected areas in cryptography – SAC 2005. Lecture notes in computer science, vol 3897. Springer, Heidelberg, pp 1–19

    Google Scholar 

  3. Barkan E, Biham E, Keller N (2008) Instant ciphertext-only cryptanalysis of GSM encrypted communication. J Cryptol 21(3):392–429

    Article  MATH  MathSciNet  Google Scholar 

  4. Biham E, Dunkelman O (2000) Cryptanalysis of the A5/1 GSM stream cipher. In: Indocrypt 2000. Lecture notes in computer science, vol 1977. Springer, Heidelberg, pp 43–51

    Google Scholar 

  5. Biryukov A, Shamir A, Wagner D (2000) Real time attack of A5/1 on a PC. In: Fast software encryption – FSE 2000. Lecture notes in computer science, vol 1978. Springer, Heidelberg, pp 1–18

    Google Scholar 

  6. Ekdahl P, Johansson T (2003) Another attack on A5/1. IEEE Trans Inform Theory 49(1):284–289

    Article  MATH  MathSciNet  Google Scholar 

  7. Maximov A, Johansson T, Babbage S (2004) An improved correlation attack on A5/1. In: Selected areas in cryptography – SAC 2004. Lecture notes in computer science, vol 3357. Springer, Heidelberg, pp 1–18

    Google Scholar 

  8. Paget C, Nohl K (2009) GSM: SRSLY? In: 26th chaos communication congress – 26C3. http://events.ccc.de/congress/2009/Fahrplan/events/3654.en.html

  9. Petrović S, Fúster-Sabater A (2000) Cryptanalysis of the A5/2 algorithm. Cryptology ePrint Archive, Report 2000/052. Available on http://eprint.iacr.org/. Accessed Oct 2000

Download references

Author information

Authors and Affiliations

  1. Project-Team SECRET, INRIA Paris-Rocquencourt, B.P. 105, 78153, Le Chesnay, France

    Anne Canteaut Prof.

Authors
  1. Anne Canteaut Prof.
    View author publications

    You can also search for this author in PubMed Google Scholar

Editor information

Editors and Affiliations

  1. Department of Mathematics and Computing Science, Eindhoven University of Technology, 5600 MB, Eindhoven, The Netherlands

    Henk C. A. van Tilborg

  2. Center for Secure Information Systems, George Mason University, Fairfax, VA, 22030-4422, USA

    Sushil Jajodia

Rights and permissions

Reprints and permissions

Copyright information

© 2011 Springer Science+Business Media, LLC

About this entry

Cite this entry

Canteaut, A. (2011). A5/1. In: van Tilborg, H.C.A., Jajodia, S. (eds) Encyclopedia of Cryptography and Security. Springer, Boston, MA. https://doi.org/10.1007/978-1-4419-5906-5_332

Download citation

Publish with us

Policies and ethics

Search

Navigation