Data Is a Stream: Security of Stream-Based Channels

  • Marc Fischlin
  • Felix Günther
  • Giorgia Azzurra Marson
  • Kenneth G. Paterson
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 9216)


The common approach to defining secure channels in the literature is to consider transportation of discrete messages provided via atomic encryption and decryption interfaces. This, however, ignores that many practical protocols (including TLS, SSH, and QUIC) offer streaming interfaces instead, moreover with the complexity that the network (possibly under adversarial control) may deliver arbitrary fragments of ciphertexts to the receiver. To address this deficiency, we initiate the study of stream-based channels and their security. We present notions of confidentiality and integrity for such channels, akin to the notions for atomic channels, but taking the peculiarities of streams into account. We provide a composition result for our setting, saying that combining chosen-plaintext confidentiality with integrity of the transmitted ciphertext stream lifts confidentiality of the channel to chosen-ciphertext security. Notably, for our proof of this theorem in the streaming setting we need an additional property, called error predictability. We finally give an AEAD-based construction that achieves our notion of a secure stream-based channel. The construction matches rather well the one used in TLS, providing validation of that protocol’s design.


Secure channel Data stream AEAD Confidentiality Integrity 



The authors thank the anonymous reviewers for their valuable comments. Marc Fischlin is supported by the Heisenberg grant Fi 940/3-2 of the German Research Foundation (DFG). Kenneth Paterson is supported by EPSRC Leadership Fellowship EP/H005455/1 and by EPSRC grant EP/M013472/1. This work has been co-funded by the DFG as part of projects P2 and S4 within the CRC 1119 CROSSING and by the EU COST Action IC 1306.


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Copyright information

© International Association for Cryptologic Research 2015

Authors and Affiliations

  • Marc Fischlin
    • 1
  • Felix Günther
    • 1
  • Giorgia Azzurra Marson
    • 1
  • Kenneth G. Paterson
    • 2
  1. 1.CryptoplexityTechnische Universität DarmstadtDarmstadtGermany
  2. 2.Information Security Group, Royal HollowayUniversity of LondonLondonUK

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