Counter Mode for Long Messages and a Long Nonce

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review


This paper proposes “Compound-CTR” mode—a simple variation of Counter mode (CTR) with an n bits block cipher. Its goal is to increase the allowed length of a single message and the total number of messages that can be encrypted under a single key. Compound-CTR encrypts a message and a (randomly chosen) nonce with length greater or equal n bits. It uses a master key to derive a nonce-based encryption key and subsequently uses it for encrypting the message in CTR mode. We show how Compound-CTR mode achieves its goal and explain why it can be used as a valid variation of CTR mode that could be of interest in some practical scenarios. Compared to CTR mode, the overhead of Compound-CTR is only the per-message key derivation and one extra key expansion (for the block cipher). We show here key derivation options that require only a few extra block cipher calls.

Original languageEnglish
Title of host publicationCyber Security, Cryptology, and Machine Learning - 6th International Symposium, CSCML 2022, Proceedings
EditorsShlomi Dolev, Amnon Meisels, Jonathan Katz
PublisherSpringer Science and Business Media Deutschland GmbH
Number of pages8
ISBN (Print)9783031076886
StatePublished - 2022
Event6th International Symposium on Cyber Security Cryptography and Machine Learning, CSCML 2022 - Beer Sheva, Israel
Duration: 30 Jun 20221 Jul 2022

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Volume13301 LNCS
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349


Conference6th International Symposium on Cyber Security Cryptography and Machine Learning, CSCML 2022
CityBeer Sheva

Bibliographical note

Publisher Copyright:
© 2022, Springer Nature Switzerland AG.


  • Block ciphers
  • Counter mode
  • Modes of operation

ASJC Scopus subject areas

  • Theoretical Computer Science
  • General Computer Science


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