On provable security of some public key encryption schemes

Download

index.pdf

Date

2012

Author

Hanoymak, Turgut

Metadata

Show full item record

Item Usage Stats

243
views

143
downloads

In this thesis, we analyse the security criteria of some public key encryption schemes. In this respect, we present the notion of adversarial goals and adversarial capabilities. We give the definition of provably security by means of several games between the challenger and the adversary in some security models, namely the standard model and the random oracle model. We state the main differences between these two models and observe the advantage of the success probability of the adversary in breaking the cryptographic schemes. We search the ways of making more efficient and provably secure encryption schemes under weak assumptions. In this context, we examine the constructions of some public key encryption schemes such as RSA, ElGamal, Cramer-Shoup, Paillier, Damgard and finally Zheng-Seberry schemes and discuss under which circumstances they satisfy which security notions. Finally, we modify one of the schemes proposed by Zheng-Seberry -which is based on ElGamal signature- by adapting Schnorr signature in order to enhance the efficiency and give a rigorous proof of security in the random oracle model.

Subject Keywords

Data encryption (Computer science)., Computer security., Cryptography.

URI

http://etd.lib.metu.edu.tr/upload/12615263/index.pdf
https://hdl.handle.net/11511/22176

Collections

Graduate School of Applied Mathematics, Thesis

Suggestions

OpenMETU
Core

On the efficient implementation of RSA Güner, Hatice Kübra; Cenk, Murat; Department of Cryptography (2015) Modular exponentiation is an essential operation for many asymmetric key cryptosystems such as RSA in which encryption and decryption are based on modular exponentiation. Therefore, efficiency of the system is effected with running time of the modular exponentiation algorithm. At the same time, key sizes also influence the efficiency of the algorithm. Over the years key sizes had to be increased to provide security. To make RSA practical, one of usable choices is acceleration of the modular exponentiation a...
A Survey on the provable security using indistinguishability notion on cryptographic encryption schemes Ayar, Emre; Doğanaksoy, Ali; Koçak, Onur; Department of Cryptography (2018) For an encryption scheme, instead of Shannon's perfect security definition, Goldwasser and Micali defined a realistic provable security called semantic security. Using indistinguishability notion, one can define security levels according to the polynomial time adversaries' capabilities such as chosen plaintext attacks (CPA) and chosen ciphertext attacks (CCA) for both symmetric and asymmetric encryption schemes in addition to the hard mathematical problems the algorithms based on. Precautions to prevent the...
Specification and verification of confidentiality in software architectures Ulu, Cemil; Oğuztüzün, Mehmet Halit S.; Department of Computer Engineering (2004) This dissertation addresses the confidentiality aspect of the information security problem from the viewpoint of the software architecture. It presents a new approach to secure system design in which the desired security properties, in particular, confidentiality, of the system are proven to hold at the architectural level. The architecture description language Wright is extended so that confidentiality authorizations can be specified. An architectural description in Wright/c, the extended language, assigns...
On Hiding a Plaintext Length by Preencryption Tezcan, Cihangir (2011-01-01) It is a well known fact that encryption schemes cannot hide a plaintext length when it is unbounded. We thus admit that an approximation of it may leak and we focus on hiding its precise value. Some standards such as TLS or SSH offer to do it by applying some pad-then-encrypt techniques. In this study, we investigate the information leakage when these techniques are used. We define the notion of padding scheme and its associated security. We show that when a padding length is uniformly distributed, the sche...
New methods for public key cryptosystems based on XTR AKLEYLEK, SEDAT; KIRLAR, Barış Bülent (2015-12-01) In this paper, we propose novel deterministic and probabilistic public key cryptographic schemes based on an effective and compact subgroup trace representation cryptosystem to handle with the problem of secure and efficient communication between the server and resource-constrained device. The proposed schemes use the hardness of the Trace-discrete logarithmic like problem. We also show that the deterministic version of the proposed scheme is a one-way trapdoor, and the probabilistic version of the proposed...

Citation Formats

T. Hanoymak, “On provable security of some public key encryption schemes,” Ph.D. - Doctoral Program, Middle East Technical University, 2012.