Paper 2016/1028

Ratcheted Encryption and Key Exchange: The Security of Messaging

Mihir Bellare, Asha Camper Singh, Joseph Jaeger, Maya Nyayapati, and Igors Stepanovs

Abstract

We aim to understand, formalize and provably achieve the goals underlying the core key-ratcheting technique of Borisov, Goldberg and Brewer, extensions of which are now used in secure messaging systems. We give syntax and security definitions for ratcheted encryption and key-exchange. We give a proven-secure protocol for ratcheted key exchange. We then show how to generically obtain ratcheted encryption from ratcheted key-exchange and standard encryption.

Note: Fixed the upper bounds provided for the security of ODHE in ROM assumption in Appendix A.

Metadata
Available format(s)
PDF
Category
Cryptographic protocols
Publication info
A major revision of an IACR publication in CRYPTO 2017
Keywords
symmetric encryptionforward securitybackward securityauthenticated key exchangeDiffie-HellmanOff-the-Record Messaging protocolSignal protocol
Contact author(s)
istepano @ eng ucsd edu
History
2019-03-16: last of 3 revisions
2016-11-01: received
See all versions
Short URL
https://ia.cr/2016/1028
License
Creative Commons Attribution
CC BY

BibTeX

@misc{cryptoeprint:2016/1028,
      author = {Mihir Bellare and Asha Camper Singh and Joseph Jaeger and Maya Nyayapati and Igors Stepanovs},
      title = {Ratcheted Encryption and Key Exchange: The Security of Messaging},
      howpublished = {Cryptology ePrint Archive, Paper 2016/1028},
      year = {2016},
      note = {\url{https://eprint.iacr.org/2016/1028}},
      url = {https://eprint.iacr.org/2016/1028}
}
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