Revisiting Turning Online Cipher Off

Ritam Bhaumik; Mridul Nandi

Paper 2015/813

Revisiting Turning Online Cipher Off

Ritam Bhaumik and Mridul Nandi

Abstract

In 'Turning Online Ciphers Off', a class of constructions was defined based on layers of secure online ciphers interleaved with simple mixing layers (like reversing and block-shifting). Here we show that an SPRP construction proposed in the work cited is insecure. Howevewr, the same construction is secure under the assumption that the underlying construction is online-but-last ciphers. We include a simpler proof for beyond-birthday security of other constructions proposed in the same work.

Metadata

Available format(s): PDF
Category: Secret-key cryptography
Publication info: Preprint. MINOR revision.
Keywords: symmetric-key cryptography cryptanalysis SPRP security provable security online online ciphers
Contact author(s): bhaumik ritam @ gmail com
History: 2015-08-17: received
Short URL: https://ia.cr/2015/813
License: CC BY

BibTeX

@misc{cryptoeprint:2015/813,
      author = {Ritam Bhaumik and Mridul Nandi},
      title = {Revisiting Turning Online Cipher Off},
      howpublished = {Cryptology ePrint Archive, Paper 2015/813},
      year = {2015},
      note = {\url{https://eprint.iacr.org/2015/813}},
      url = {https://eprint.iacr.org/2015/813}
}