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T0RTT: Non-Interactive Immediate Forward-Secret Single-Pass Circuit Construction

Sebastian Lauer, Kai Gellert, Robert Merget, Tobias Handirk, Jörg Schwenk
2020 Proceedings on Privacy Enhancing Technologies  
It was even conjectured that it is impossible to achieve both message complexity 𝒪(n) and forward secrecy immediately after circuit construction (so-called immediate forward secrecy).  ...  The circuit construction protocol (CCP) negotiates cryptographic keys for Tor circuits, which overlay TCP/IP by routing Tor cells over n onion routers.  ...  [32] to circuit construction protocols and disprove this assumption by proposing a new non-interactive single-pass circuit construction protocol that utilizes non-static secret keys and achieves immediate  ... 
doi:10.2478/popets-2020-0030 fatcat:q3rlcpz37ffqxok2v3wxrndjke

A Modern View on Forward Security

Colin Boyd, Kai Gellert
2020 Computer journal  
Forward security ensures that compromise of entities today does not impact the security of cryptographic primitives employed in the past.  ...  We survey existing methods for achieving forward security for different cryptographic primitives and propose new definitions and terminology aimed at a unified treatment of the notion.  ...  achieved in their non-interactive constructions.  ... 
doi:10.1093/comjnl/bxaa104 fatcat:4rmqca3iabh2plsmjif7ai25je

Bloom Filter Encryption and Applications to Efficient Forward-Secret 0-RTT Key Exchange

David Derler, Kai Gellert, Tibor Jager, Daniel Slamanig, Christoph Striecks
2021 Journal of Cryptology  
This gives rise to the first forward-secret 0-RTT protocols that are efficient enough to be deployed in practice. We believe that BFE will find applications beyond forward-secret 0-RTT protocols.  ...  Only recently, the first forward-secret 0-RTT protocol was described by Günther et al. (Eurocrypt, 2017). It is based on puncturable encryption.  ...  [40] introduce a single-pass circuit construction protocol with forward secrecy for Tor, called Tor 0-RTT (T0RTT), which they construct from BFE. Dallmeier et al.  ... 
doi:10.1007/s00145-021-09374-3 fatcat:ietc5dqgobc2jnkwb7gxhytvo4

Construction and Security Analysis of 0-RTT Protocols

Kai Gellert, Bergische Universität Wuppertal
However, this view limits the understanding of what forward security should mean in a non-interactive setting.  ...  Hence, we propose new terminology for a unified treatment of forward security, capturing both interactive and non-interactive communication settings.  ...  T0RTT: Non-interactive immediate forward-secret single-pass circuit con- struction. Proceedings on Privacy Enhancing Technologies, 2020(2):336-357, 2020.  ... 
doi:10.25926/eg6a-6059 fatcat:vbovkkpfhvazbe6u74kevsefu4