scholarly journals Modeling advanced security aspects of key exchange and secure channel protocols

2020 ◽  
Vol 62 (5-6) ◽  
pp. 287-293
Author(s):  
Felix Günther
Keyword(s):  
Building Blocks ◽  
Key Exchange ◽  
Internet Security ◽  
Streaming Data ◽  
Transport Layer ◽  
Security Model ◽  
Secret Key ◽  
Multi Stage ◽  
Key Exchange Protocols ◽  
Secure Channel

AbstractSecure connections are at the heart of today’s Internet infrastructure, protecting the confidentiality, authenticity, and integrity of communication. Achieving these security goals is the responsibility of cryptographic schemes, more specifically two main building blocks of secure connections. First, a key exchange protocol is run to establish a shared secret key between two parties over a, potentially, insecure connection. Then, a secure channel protocol uses that shared key to securely transport the actual data to be exchanged. While security notions for classical designs of these components are well-established, recently developed and standardized major Internet security protocols like Google’s QUIC protocol and the Transport Layer Security (TLS) protocol version 1.3 introduce novel features for which supporting security theory is lacking.In my dissertation [20], which this article summarizes, I studied these novel and advanced design aspects, introducing enhanced security models and analyzing the security of deployed protocols. For key exchange protocols, my thesis introduces a new model for multi-stage key exchange to capture that recent designs for secure connections establish several cryptographic keys for various purposes and with differing levels of security. It further introduces a formalism for key confirmation, reflecting a long-established practical design criteria which however was lacking a comprehensive formal treatment so far. For secure channels, my thesis captures the cryptographic subtleties of streaming data transmission through a revised security model and approaches novel concepts to frequently update key material for enhanced security through a multi-key channel notion. These models are then applied to study (and confirm) the security of the QUIC and TLS 1.3 protocol designs.

scholarly journals A Cryptographic Analysis of the TLS 1.3 Handshake Protocol

2021 ◽  
Vol 34 (4) ◽  
Author(s):  
Benjamin Dowling ◽  
Marc Fischlin ◽  
Felix Günther ◽  
Douglas Stebila
Keyword(s):  
Key Exchange ◽  
Transport Layer ◽  
Security Model ◽  
Round Trip Time ◽  
Round Trip ◽  
Trip Time ◽  
Diffie Hellman ◽  
Multi Stage ◽  
Handshake Protocol ◽  
The Many

AbstractWe analyze the handshake protocol of the Transport Layer Security (TLS) protocol, version 1.3. We address both the full TLS 1.3 handshake (the one round-trip time mode, with signatures for authentication and (elliptic curve) Diffie–Hellman ephemeral ((EC)DHE) key exchange), and the abbreviated resumption/“PSK” mode which uses a pre-shared key for authentication (with optional (EC)DHE key exchange and zero round-trip time key establishment). Our analysis in the reductionist security framework uses a multi-stage key exchange security model, where each of the many session keys derived in a single TLS 1.3 handshake is tagged with various properties (such as unauthenticated versus unilaterally authenticated versus mutually authenticated, whether it is intended to provide forward security, how it is used in the protocol, and whether the key is protected against replay attacks). We show that these TLS 1.3 handshake protocol modes establish session keys with their desired security properties under standard cryptographic assumptions.

scholarly journals A Prototype Model of Virtual Authenticated Key Exchange Mechanism over Secured Channel in Ad-Hoc Environment

2020 ◽  
Vol 8 (5) ◽  
pp. 5526-5532
Keyword(s):  
Ad Hoc ◽  
Vital Role ◽  
Key Exchange ◽  
Exchange Mechanism ◽  
Prototype Model ◽  
Secret Key ◽  
Private Key ◽  
Computational Overhead ◽  
Key Exchange Protocols ◽  
Symmetric Key

Key exchange protocols play a vital role in symmetric key cryptography. The transfer of private key through the secured medium is a challenging task because every day the intruders are evolved and the attacks are increasing constantly. The existing key exchange protocols such as Diffie-Hellman, Elgamal, and MQV, etc. are the old methods and many attacks happened on those protocols. That challenges demanding new protocol or methodology of transferring secret key between the parties. The paper proposes a new, secured, less computational overhead key exchange mechanism using short message service available in the cellular networks. GSM-SMS is a highly established secured channel and the research uses this facility to transfer the key between senders to a receiver of the symmetric key cryptosystem. The private key no need to reveal to third parties or even the receiver because the sender can directly communicate to the decryption system through the mobile SMS. After the decryption process, the secret key will be destroyed immediately. There is no possible attack during the key transfer and loss and error of the communication are very less.

Horizontal Side-Channel Vulnerabilities of Post-Quantum Key Exchange and Encapsulation Protocols

2021 ◽  
Vol 20 (6) ◽  
pp. 1-22
Author(s):  
Furkan Aydin ◽  
Aydin Aysu ◽  
Mohit Tiwari ◽  
Andreas Gerstlauer ◽  
Michael Orshansky
Keyword(s):  
Key Exchange ◽  
Power Measurement ◽  
Side Channel ◽  
Digital Information ◽  
Secret Key ◽  
Secret Keys ◽  
Key Exchange Protocols ◽  
Horizontal Side ◽  
Single Trace ◽  
Lattice Based Cryptography

Key exchange protocols and key encapsulation mechanisms establish secret keys to communicate digital information confidentially over public channels. Lattice-based cryptography variants of these protocols are promising alternatives given their quantum-cryptanalysis resistance and implementation efficiency. Although lattice cryptosystems can be mathematically secure, their implementations have shown side-channel vulnerabilities. But such attacks largely presume collecting multiple measurements under a fixed key, leaving the more dangerous single-trace attacks unexplored. This article demonstrates successful single-trace power side-channel attacks on lattice-based key exchange and encapsulation protocols. Our attack targets both hardware and software implementations of matrix multiplications used in lattice cryptosystems. The crux of our idea is to apply a horizontal attack that makes hypotheses on several intermediate values within a single execution all relating to the same secret, and to combine their correlations for accurately estimating the secret key. We illustrate that the design of protocols combined with the nature of lattice arithmetic enables our attack. Since a straightforward attack suffers from false positives, we demonstrate a novel extend-and-prune procedure to recover the key by following the sequence of intermediate updates during multiplication. We analyzed two protocols, Frodo and FrodoKEM , and reveal that they are vulnerable to our attack. We implement both stand-alone hardware and RISC-V based software realizations and test the effectiveness of the proposed attack by using concrete parameters of these protocols on physical platforms with real measurements. We show that the proposed attack can estimate secret keys from a single power measurement with over 99% success rate.

One-Round Attribute-Based Key Exchange in the Multi-Party Setting

2017 ◽  
Vol 28 (06) ◽  
pp. 725-742 ◽  
Author(s):  
Yangguang Tian ◽  
Guomin Yang ◽  
Yi Mu ◽  
Shiwei Zhang ◽  
Kaitai Liang ◽  
...  
Keyword(s):  
Random Oracle Model ◽  
Random Oracle ◽  
Key Exchange ◽  
Secret Key ◽  
Security Issue ◽  
User Privacy ◽  
Session Key ◽  
Shared Secret ◽  
Key Exchange Protocols ◽  
Straightforward Approach

Attribute-based authenticated key exchange (AB-AKE) is a useful primitive that allows a group of users to establish a shared secret key and at the same time enables fine-grained access control. A straightforward approach to design an AB-AKE protocol is to extend a key exchange protocol using an attribute-based authentication technique. However, insider security is a challenge security issue for AB-AKE in the multi-party setting and cannot be solved using the straightforward approach. In addtion, many existing key exchange protocols for the multi-party setting (e.g., the well-known Burmester-Desmedt protocol) require multiple broadcast rounds to complete the protocol. In this paper, we propose a novel one-round attribute-based key exchange (OAKE) protocol in the multi-party setting. We define the formal security models, including session key security, insider security and user privacy, for OAKE, and prove the security of the proposed protocol under some standard assumptions in the random oracle model.

scholarly journals Compiled Constructions towards Post-Quantum Group Key Exchange: A Design from Kyber

Mathematics ◽  
2020 ◽  
Vol 8 (10) ◽  
pp. 1853
Author(s):  
José Ignacio Escribano Pablos ◽  
María Isabel González Vasco ◽  
Misael Enrique Marriaga ◽  
Ángel Luis Pérez del Pozo
Keyword(s):  
Random Oracle Model ◽  
Building Blocks ◽  
Random Oracle ◽  
Key Exchange ◽  
Encryption Scheme ◽  
Secret Key ◽  
Key Exchange Protocol ◽  
Group Key ◽  
Group Key Exchange ◽  
Starting Point

A group authenticated key exchange (GAKE) protocol allows a set of parties belonging to a certain designated group to agree upon a common secret key through an insecure communication network. In the last few years, many new cryptographic tools have been specifically designed to thwart attacks from adversaries which may have access to (different kinds of) quantum computation resources. However, few constructions for group key exchange have been put forward. Here, we propose a four-round GAKE which can be proven secure under widely accepted assumptions in the Quantum Random Oracle Model. Specifically, we integrate several primitives from the so-called Kyber suite of post-quantum tools in a (slightly modified) compiler from Abdalla et al. (TCC 2007). More precisely, taking as a starting point an IND-CPA encryption scheme from the Kyber portfolio, we derive, using results from Hövelmanns et al. (PKC 2020), a two-party key exchange protocol and an IND-CCA encryption scheme and prove them fit as building blocks for our compiled construction. The resulting GAKE protocol is secure under the Module-LWE assumption, and furthermore achieves authentication without the use of (expensive) post-quantum signatures.

scholarly journals Password-Only Authenticated Three-Party Key Exchange with Provable Security in the Standard Model

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Junghyun Nam ◽  
Kim-Kwang Raymond Choo ◽  
Junghwan Kim ◽  
Hyun-Kyu Kang ◽  
Jinsoo Kim ◽  
...  
Keyword(s):  
Security Analysis ◽  
Random Oracle ◽  
Key Exchange ◽  
Secret Key ◽  
Random Oracles ◽  
Insider Attack ◽  
Password Security ◽  
Authentication Server ◽  
The Standard Model ◽  
Key Exchange Protocols

Protocols for password-only authenticated key exchange (PAKE) in the three-party setting allow two clients registered with the same authentication server to derive a common secret key from their individual password shared with the server. Existing three-party PAKE protocols were proven secure under the assumption of the existence of random oracles or in a model that does not consider insider attacks. Therefore, these protocols may turn out to be insecure when the random oracle is instantiated with a particular hash function or an insider attack is mounted against the partner client. The contribution of this paper is to present the first three-party PAKE protocol whose security is proven without any idealized assumptions in a model that captures insider attacks. The proof model we use is a variant of the indistinguishability-based model of Bellare, Pointcheval, and Rogaway (2000), which is one of the most widely accepted models for security analysis of password-based key exchange protocols. We demonstrated that our protocol achieves not only the typical indistinguishability-based security of session keys but also the password security against undetectable online dictionary attacks.

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