On Hiding a Plaintext Length by Preencryption

Download

index.pdf

Date

2011-01-01

Author

Tezcan, Cihangir

Metadata

Show full item record

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Item Usage Stats

244
views

162
downloads

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 scheme is nearly optimal. We also show that the insecurity degrades linearly with the padding length.

Subject Keywords

Encryption, IPSEC, SSH

URI

https://hdl.handle.net/11511/29853

DOI

https://doi.org/10.1007/978-3-642-21554-4_20

Collections

Graduate School of Informatics, Conference / Seminar

Suggestions

OpenMETU
Core

On provable security of some public key encryption schemes Hanoymak, Turgut; Akyıldız, Ersan; Selçuk, Ali Aydın; Department of Cryptography (2012) 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 cr...
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...
On Measuring Security Bounds of Some Ciphers Using Mixed Integer Linear Programming (MILP) Approach Türesin, Can; Doğanaksoy, Ali; Koçak, Onur; Department of Cryptography (2021-9-6) Block ciphers are one of the symmetric key encryption algorithms that are used in many devices. Its increasing popularity has led to the emergence of new cryptanalysis methods. Therefore, measuring block cipher's security bounds is one main indispensable need for its designers. Two of the most effective attacks on block ciphers are differential and linear cryptanalysis and these attacks' efficiencies are bonded with a number of active S-boxes of the cipher after a certain number of rounds. Consequently, mea...
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...
Modular exponentiation methods in cryptography Yünüak, Hasan Bartu; Cenk, Murat; Department of Cryptography (2017) Modular exponentiation has an important role in many cryptographic algorithms. These exponentiation methods differ in the bases used and their representations, the repeating aspect, and for which algorithms they are used for: fixed or variable base. Our research aims to compare the efficiencies and implementation timings for some selected algorithms. Also, we look at the options for using a dedicated cubing algorithm, and compare them with the current algorithms.

Citation Formats

C. Tezcan, “On Hiding a Plaintext Length by Preencryption,” 2011, vol. 6715, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/29853.