2,334 research outputs found
Isogeny-based post-quantum key exchange protocols
The goal of this project is to understand and analyze the supersingular isogeny Diffie Hellman (SIDH), a post-quantum key exchange protocol which security lies on the isogeny-finding problem between supersingular elliptic curves. In order to do so, we first introduce the reader to cryptography focusing on key agreement protocols and motivate the rise of post-quantum cryptography as a necessity with the existence of the model of quantum computation. We review some of the known attacks on the SIDH and finally study some algorithmic aspects to understand how the protocol can be implemented
A Framework for Efficient Adaptively Secure Composable Oblivious Transfer in the ROM
Oblivious Transfer (OT) is a fundamental cryptographic protocol that finds a
number of applications, in particular, as an essential building block for
two-party and multi-party computation. We construct a round-optimal (2 rounds)
universally composable (UC) protocol for oblivious transfer secure against
active adaptive adversaries from any OW-CPA secure public-key encryption scheme
with certain properties in the random oracle model (ROM). In terms of
computation, our protocol only requires the generation of a public/secret-key
pair, two encryption operations and one decryption operation, apart from a few
calls to the random oracle. In~terms of communication, our protocol only
requires the transfer of one public-key, two ciphertexts, and three binary
strings of roughly the same size as the message. Next, we show how to
instantiate our construction under the low noise LPN, McEliece, QC-MDPC, LWE,
and CDH assumptions. Our instantiations based on the low noise LPN, McEliece,
and QC-MDPC assumptions are the first UC-secure OT protocols based on coding
assumptions to achieve: 1) adaptive security, 2) optimal round complexity, 3)
low communication and computational complexities. Previous results in this
setting only achieved static security and used costly cut-and-choose
techniques.Our instantiation based on CDH achieves adaptive security at the
small cost of communicating only two more group elements as compared to the
gap-DH based Simplest OT protocol of Chou and Orlandi (Latincrypt 15), which
only achieves static security in the ROM
Key establishment --- security models, protocols and usage
Key establishment is the process whereby two or more parties derive a shared
secret, typically used for subsequent confidential communication. However,
identifying the exact security requirements for key establishment protocols is
a non-trivial task. This thesis compares, extends and merges existing security
definitions and models for key establishment protocols.
The primary focus is on two-party key agreement schemes in the public-key
setting. On one hand new protocols are proposed and analyzed in the existing
Canetti-Krawzcyk model. On the other hand the thesis develops a security model
and novel definition that capture the essential security attributes of the
standardized Unified Model key agreement protocol. These analyses lead to the
development of a new security model and related definitions that combine and
extend the Canetti-Krawzcyk pre- and post- specified peer models in terms of
provided security assurances.
The thesis also provides a complete analysis of a one-pass key establishment
scheme. There are security goals that no one-pass key establishment scheme can
achieve, and hence the two-pass security models and definitions need to be
adapted for one-pass protocols. The analysis provided here includes
the description of the required modification to the underlying security model.
Finally, a complete security argument meeting these altered conditions is
presented as evidence supporting the security of the one-pass scheme.
Lastly, validation and reusing short lived key pairs are related to
efficiency, which is a major objective in practice. The thesis considers the
formal implication of omitting validation steps and reusing short lived key
pairs. The conclusions reached support the generally accepted cryptographic
conventions that incoming messages should not be blindly trusted and extra
care should be taken when key pairs are reused
Public-Key Based Authentication Architecture for IoT Devices Using PUF
Nowadays, Internet of Things (IoT) is a trending topic in the computing
world. Notably, IoT devices have strict design requirements and are often
referred to as constrained devices. Therefore, security techniques and
primitives that are lightweight are more suitable for such devices, e.g.,
Static Random-Access Memory (SRAM) Physical Unclonable Functions (PUFs) and
Elliptic Curve Cryptography (ECC). SRAM PUF is an intrinsic security primitive
that is seeing widespread adoption in the IoT segment. ECC is a public-key
algorithm technique that has been gaining popularity among constrained IoT
devices. The popularity is due to using significantly smaller operands when
compared to other public-key techniques such as RSA (Rivest Shamir Adleman).
This paper shows the design, development, and evaluation of an
application-specific secure communication architecture based on SRAM PUF
technology and ECC for constrained IoT devices. More specifically, it
introduces an Elliptic Curve Diffie-Hellman (ECDH) public-key based
cryptographic protocol that utilizes PUF-derived keys as the root-of-trust for
silicon authentication. Also, it proposes a design of a modular hardware
architecture that supports the protocol. Finally, to analyze the practicality
as well as the feasibility of the proposed protocol, we demonstrate the
solution by prototyping and verifying a protocol variant on the commercial
Xilinx Zynq-7000 APSoC device
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