Closing the Loop: Bidirectional Fully Encrypted Protocols
Researchers show naively composing unidirectional fully encrypted protocols is detectable and construct provably secure bidirectional FEPs, validated in Rust.
The paper introduces formal security definitions for bidirectional fully encrypted protocols (BiFEPs), covering exact shaping, delivery, protocol-state integrity, private half-close, and cross-direction isolation. It shows trivially composing two unidirectional FEPs enables detection attacks via cross-direction dependencies like traffic imbalance and connection tear-down. The authors construct provably secure BiFEPs for datastream and datagram settings, validated with a Rust implementation; no surveyed deployed protocol provides the full set of properties.
- Naive composition of unidirectional FEPs detectable via traffic imbalance and tear-down patterns
- New definitions cover shaping, protocol-state integrity, private half-close, cross-direction isolation
- Provably secure constructions for both datastream and datagram settings
- Rust implementation; no deployed protocol satisfies all BiFEP properties
From the original article
1 min read at arxiv.orgFully encrypted protocols (FEPs) provide encrypted channels that make all protocol-generated bytes computationally indistinguishable from uniform random strings. Several previous works have explored security definitions and constructions of unidirectional FEPs: protocols in which one party acts only as a sender, and the other acts only as a receiver.
By Baigang Chen · arxiv.org
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