Paper 2023/913 Original: eprint.iacr.org/2023/913 ↗

Hidden Stream Ciphers and TMTO Attacks on TLS 1.3, DTLS 1.3, QUIC, and Signal

John Preuß Mattsson
Abstract

Transport Layer Security (TLS) 1.3 and the Signal protocol are very important and widely used security protocols. We show that the key update function in TLS 1.3 and the symmetric key ratchet in Signal can be modeled as non-additive synchronous stream ciphers. This means that the efficient Time Memory Tradeoff Attacks for stream ciphers can be applied. The implication is that TLS 1.3, QUIC, DTLS 1.3, and Signal offer a lower security level against TMTO attacks than expected from the key sizes. We provide detailed analyses of the key update mechanisms in TLS 1.3 and Signal, illustrate the importance of ephemeral key exchange, and show that the process that DTLS 1.3 and QUIC use to calculate AEAD limits is flawed. We provide many concrete recommendations for the analyzed protocols.

Metadata
Available format(s)
PDF
Category
Cryptographic protocols
Publication info
Preprint.
History
2023-12-15: last updated
2023-06-12: published
Short URL
https://ia.cr/2023/913
License
https://creativecommons.org/licenses/by/4.0/

BibTeX

@misc{cryptoeprint:2023/913,
      author = {John Preuß Mattsson},
      title = {Hidden Stream Ciphers and TMTO Attacks on TLS 1.3, DTLS 1.3, QUIC, and Signal},
      howpublished = {Cryptology {ePrint} Archive, Paper 2023/913},
      year = {2023},
      url = {https://eprint.iacr.org/2023/913}
}
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