# Modelling Time, or A Step Towards Reduction-based Security Proofs for OTP and Kerberos

@article{Schwenk2013ModellingTO, title={Modelling Time, or A Step Towards Reduction-based Security Proofs for OTP and Kerberos}, author={J{\"o}rg Schwenk}, journal={IACR Cryptol. ePrint Arch.}, year={2013}, volume={2013}, pages={604} }

The notion of time plays an important role in many practically deployed cryptographic protocols, ranging from OneTime-Password (OTP) tokens to the Kerberos protocol. However, time is difficult to model in a Turing machine environment. We propose the first such model, where time is modelled as a global counter T . We argue that this model closely matches several implementations of time in computer environments. The usefulness of the model is shown by giving complexity-theoretic security proofs… Expand

#### 2 Citations

Modelling Time for Authenticated Key Exchange Protocols

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This work argues that this model closely matches several implementations of time in computer environments, and gives complexity-theoretic security proofs for OTP protocols and HMQV-like one-round AKE protocols. Expand

Authenticated Network Time Synchronization

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An authenticated version of NTP is presented, called ANTP, to protect against desynchronization attacks and achieve secure time synchronization under standard cryptographic assumptions, using a novel provable security framework that involves adversary control of time. Expand

#### References

SHOWING 1-10 OF 44 REFERENCES

Cryptographically Sound Security Proofs for Basic and Public-Key Kerberos

- Computer Science
- ESORICS
- 2006

A computational analysis of basic Kerbero and Kerberos with public-key authentication (PKINIT) in which authentication and key secrecy properties are considered and symbolic correctness results attained in the Dolev-Yao model are extended to cryptographically sound results in the computational model. Expand

Examining Indistinguishability-Based Proof Models for Key Establishment Protocols

- Mathematics, Computer Science
- ASIACRYPT
- 2005

This work considers several variants of indistinguishability-based proof models for key establishment protocols, identifies several subtle differences between these variants and models, and compares the relative strengths of the notions of security between the models. Expand

Computationally sound mechanized proofs for basic and public-key Kerberos

- Computer Science
- ASIACCS '08
- 2008

We present a computationally sound mechanized analysis of Kerberos 5, both with and without its public-key extension PKINIT. We prove authentication and key secrecy properties using the prover… Expand

Provably secure session key distribution: the three party case

- Computer Science
- STOC '95
- 1995

This paper provides the first treatment of session key distribution in the three-party setting of Needham and Schroeder in the complexity-theoretic framework of modern cryptography, assuming the (minimal) assumption of a pseudorandom function. Expand

Formal Modeling and Analyzing Kerberos Protocol

- Computer Science
- 2009 WRI World Congress on Computer Science and Information Engineering
- 2009

This work formalizes the Kerberos protocol using CSP methods, and can prove that the system protected by the protocol is indeed secure as it declared. Expand

Kerberos Version 4: Inductive Analysis of the Secrecy Goals

- Computer Science
- ESORICS
- 1998

An operational model of crypto-protocols is tailored to the detailed analysis of the secrecy goals accomplished by Kerberos Version IV, and allows an eavesdropper to exploit the shared keys of compromised agents, and admits the accidental loss of expired session keys. Expand

A formal analysis of ome properties of kerberos 5 using MSR

- Computer Science
- Proceedings 15th IEEE Computer Security Foundations Workshop. CSFW-15
- 2002

In the abstract formalization, an authentication property about Kerberos 5 is proved and three anomalies are discovered, one of which occurs on both levels of detail, while the other two rely on the richer structure of the detailed formalization. Expand

Formal Analysis of the Kerberos Authentication System

- Computer Science
- J. Univers. Comput. Sci.
- 1997

Gurevich's Abstract State Machine formalism is used to specify the Kerberos Authentication System based on the Needham-Schroeder authentication protocol and is used as a basis both to discover the minimum assumptions to guarantee the correctness of the system and to analyse its security weaknesses. Expand

Extended Abstract: Provable-Security Analysis of Authenticated Encryption in Kerberos

- Computer Science
- 2007 IEEE Symposium on Security and Privacy (SP '07)
- 2007

A close look at Kerberos' encryption is taken and it is confirmed that most of the options in the current version provably provide privacy and authenticity, some with slight modification that is suggested. Expand

Optimally Tight Security Proofs for Hash-Then-Publish Time-Stamping

- Mathematics, Computer Science
- ACISP
- 2010

This paper achieves a notably smaller loss of power 1.5, which is the first one efficient enough to allow meaningful security guarantees to be given for a globalscale time-stamping service based on 256 bit hash functions, which considerably increases the efficiency of possible practical solutions. Expand