Cryptanalysis of WG-7: a lightweight stream cipher

Mohammad Ali Orumiehchiha, Josef Pieprzyk, Ron Steinfeld

Research output: Contribution to journalArticlepeer-review

20 Citations (Scopus)


WG-7 is a stream cipher based on WG stream cipher and has been designed by Luo et al. (2010). This cipher is designed for low cost and lightweight applications (RFID tags and mobile phones, for instance). This paper addresses cryptographic weaknesses of WG-7 stream cipher. We show that the key stream generated by WG-7 can be distinguished from a random sequence after knowing 2 13. 5 keystream bits and with a negligible error probability. Also, we investigate the security of WG-7 against algebraic attacks. An algebraic key recovery attack on this cipher is proposed. The attack allows to recover both the internal state and the secret key with the time complexity about 2 27.

Original languageEnglish
Pages (from-to)277-285
Number of pages9
JournalCryptography and Communications
Issue number3-4
Publication statusPublished - 2012


  • WG-7 stream cipher
  • cryptanalysis
  • key recovery attack
  • distinguishing attack
  • WG stream cipher


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