10,268 research outputs found
Towards Forward Secure Internet Traffic
Forward Secrecy (FS) is a security property in key-exchange algorithms which
guarantees that a compromise in the secrecy of a long-term private-key does not
compromise the secrecy of past session keys. With a growing awareness of
long-term mass surveillance programs by governments and others, FS has become
widely regarded as a highly desirable property. This is particularly true in
the TLS protocol, which is used to secure Internet communication. In this
paper, we investigate FS in pre-TLS 1.3 protocols, which do not mandate FS, but
still widely used today. We conduct an empirical analysis of over 10 million
TLS servers from three different datasets using a novel heuristic approach.
Using a modern TLS client handshake algorithms, our results show 5.37% of top
domains, 7.51% of random domains, and 26.16% of random IPs do not select FS
key-exchange algorithms. Surprisingly, 39.20% of the top domains, 24.40% of the
random domains, and 14.46% of the random IPs that do not select FS, do support
FS. In light of this analysis, we discuss possible paths toward forward secure
Internet traffic. As an improvement of the current state, we propose a new
client-side mechanism that we call "Best Effort Forward Secrecy" (BEFS), and an
extension of it that we call "Best Effort Forward Secrecy and Authenticated
Encryption" (BESAFE), which aims to guide (force) misconfigured servers to FS
using a best effort approach. Finally, within our analysis, we introduce a
novel adversarial model that we call "discriminatory" adversary, which is
applicable to the TLS protocol
On the Relations Between Diffie-Hellman and ID-Based Key Agreement from Pairings
This paper studies the relationships between the traditional Diffie-Hellman
key agreement protocol and the identity-based (ID-based) key agreement protocol
from pairings.
For the Sakai-Ohgishi-Kasahara (SOK) ID-based key construction, we show that
identical to the Diffie-Hellman protocol, the SOK key agreement protocol also
has three variants, namely \emph{ephemeral}, \emph{semi-static} and
\emph{static} versions. Upon this, we build solid relations between
authenticated Diffie-Hellman (Auth-DH) protocols and ID-based authenticated key
agreement (IB-AK) protocols, whereby we present two \emph{substitution rules}
for this two types of protocols. The rules enable a conversion between the two
types of protocols. In particular, we obtain the \emph{real} ID-based version
of the well-known MQV (and HMQV) protocol.
Similarly, for the Sakai-Kasahara (SK) key construction, we show that the key
transport protocol underlining the SK ID-based encryption scheme (which we call
the "SK protocol") has its non-ID counterpart, namely the Hughes protocol.
Based on this observation, we establish relations between corresponding
ID-based and non-ID-based protocols. In particular, we propose a highly
enhanced version of the McCullagh-Barreto protocol
Security and privacy aspects of mobile applications for post-surgical care
Mobile technologies have the potential to improve patient monitoring, medical decision making and in general the efficiency and quality of health delivery. They also pose new security and privacy challenges. The objectives of this work are to (i) Explore and define security and privacy requirements on the example of a post-surgical care application, and (ii) Develop and test a pilot implementation Post-Surgical Care Studies of surgical out- comes indicate that timely treatment of the most common complications in compliance with established post-surgical regiments greatly improve success rates. The goal of our pilot application is to enable physician to optimally synthesize and apply patient directed best medical practices to prevent post-operative complications in an individualized patient/procedure specific fashion. We propose a framework for a secure protocol to enable doctors to check most common complications for their patient during in-hospital post- surgical care. We also implemented our construction and cryptographic protocols as an iPhone application on the iOS using existing cryptographic services and libraries
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