Format and Order Revealing Encryption

As more and more cloud services emerge so does the need for new methods for securing the data these services consume, especially since data leaks have become the norm rather than the exception. Since most cloud services require some kind of access to our private data in order to perform searches and provide services, new ways of securing our data in the cloud is needed. This dissertation examines the current state of the cryptographic world in order to try to and understand and resume what solutions currently exist for this particular type of problem. This work is motivated by a particular problem of data delegation to a cloud infrastructure. This problem involves the protection of sensitive data whilst it’s analysed by a third party. While there is no simple approach to solve this particular problem, this dissertation discusses three main approaches to tackle this problem. One approach attempts to define a new cryptographic scheme with a leakage profile that would allow a third party to only have access to some information of the plaintext but, at the same time, keep the plaintext safe from attackers. Another approach attempts to use already existing cryptographic schemes, such as, Format Preserving Encryption and Order Revealing Encryption to solve this particular problem. A final approach tries to solve this problem by utilising cryptographic tools, such as hash-functions and hash-based message authentication codes. An extended study was also conducted in many cryptographic schemes, both current and old cryptographic schemes. This study allowed for a better view of the cryptographic world and how these schemes could help us achieve a solution. For this dissertation, a prototype was also implemented of some recent cryptographic schemes. These prototype implementations allowed for a deeper understanding of how these schemes work and also allowed us to conduct some experiments while trying to combine two cryptographic schemes. The results of this dissertation show that that trying to solve a problem via creating a new cryptographic scheme is not an easy feat especially when one wants to define correctly the strict security requirements and also the work needed to understand the mathematical workings of similar schemes. Lastly we conclude that solving the problem with the help of already existing tools may be the easiest solution, but, it may also only work for a specific scenario and hence is of no use in other similar situations. A solution to the particular problem studied in this thesis is also presented at the end of this dissertation, although, it only applies to this specific problem and does not solve the more general problem of privacy of data delegation to the cloud.Com a explosão de serviços baseados na nuvem que ocorre nos dias de hoje, torna-se imperativo que os dados que são consumidos por este tipo de serviços sejam de alguma forma protegidos contra ataques ou roubos[Cen18]. O principal problema com este tipo de serviços é que, normalmente, estes serviços precisam de acesso aos dados para conseguirem fazer pesquisas e correlacionar dados de forma a que seja possível fornecer diversos serviços. Esta dissertação tem como objetivo estudar o mundo da criptografia de forma a perceber que tipo de garantias são oferecidas pelos esquemas criptográficos existentes nos dias de hoje para serviços baseados na nuvem. Este trabalho é motivado por um problema real de delegação de dados para a nuvem. Este problema envolve a proteção de dados sensíveis que precisam de ser analisados por entidades externas. Embora não haja uma abordagem simples para resolver este tipo de problemas, nesta dissertação iremos discutir três abordagens que, potencialmente, poderão resolver este problema. Uma abordagem tenta definir o que poderia ser a estrutura geral de um novo esquema criptográfico que pudesse lidar com o problema específico em análise. Numa outra abordagem iremos utilizar ferramentas existentes para tentar resolver o problema em questão. Iremos também tentar unir dois esquemas criptográficos existentes, de forma a tentar combater este problema em específico. Foi também realizado um estudo a vários esquemas criptográficos de forma a perceber quais as soluções que existem hoje em dia para problemas relacionados com a delegação de dados para entidades externas, como também, tentar perceber que esquemas criptográficos que ainda são resultados meramente teóricos mas que possam vir, no futuro, a ser úteis para combater esta problemática. Os resultados desta dissertação mostram que resolver um problema relacionado com criptografia nem sempre é fácil, uma vez que, a má utilização destes esquemas poderá levar a uma falha grave de segurança. Por fim, concluímos que, resolver um problema desta natureza através de ferramentas existentes é bastante mais fácil do que tentar desenvolver esquemas criptográficos novos, mas que irá perder o poder de poder ser aplicado a outros problemas semelhantes

A Survey of Lightweight Cryptosystems for Smart Home Devices

A Smart Home uses interconnected network technology to monitor the environment, control the various physical appliances, and communicate with each other in a close environment. A typical smart home is made up of a security system, intercommunication system, lighting system, and ventilation system.  Data security schemes for smart homes are ineffective due to inefficiency cryptosystems, high energy consumption, and low exchange security. Traditional cryptosystems are less-applicable because of their large block size, large key size, and complex rounds. This paper conducts a review of smart homes, and adopts Ultra-Sooner Lightweight Cryptography to secure home door. It provides extensive background of cryptography, forms of cryptography as associated issues and strengths, current trends, smart home door system design, and future works suggestions. Specifically, there are prospects of utilizing XORed lightweight cryptosystem for developing encryption and decryption algorithms in smart home devices. The Substitution Permutation Network, and Feistel Network cryptographic primitives were most advanced forms of cipher operations with security guarantees. Therefore, better security, memory and energy efficiency can be obtained with lightweight ciphers in smart home devices when compared to existing solutions. In the subsequent studies, a blockchain-based lightweight cryptography can be the next springboard in attaining the most advanced security for smart home systems and their appliances.     &nbsp

A brief overview of modern cryptographic tools with application to Internet

Here a brief overview of some of the cryptographic tools used in Internet today is illustrated. This document briefly introduces cryptography starting from a short resume of historical events showing the evolution and role played by cryptography narrating some representative real life events in history. A more formal introduction mentioning the advantages obtainable with cryptography is then undertaken starting from symmetric and asymmetric cryptography. Other uses of cryptography are then explained to finally present two widely used communication protocols in Internet. Representative examples are provided reverting to a minimal mathematical approach

DES and TDES Performance Evaluation for Non-pipelined and Pipelined Implementations in VHDL Using the Cyclone II FPGA Technology

Two ongoing issues that engineers must face in the new era of data analytics are performance and security. Field Programmable Gate Arrays (FPGAs) offer a new solution for optimizing the performance of applications while the Data Encryption Standard (DES) and the Triple Data Encryption Standard (TDES) offer a mean to secure information. In this thesis we present a Non-Pipelined and Pipelined, in Electronic Code Book (EBC) mode, implementations in VHDL of these two commonly utilized cryptography schemes. Using Altera Cyclone II FPGA as our platform, we design and verify the implementations with the EDA tools provided by Altera. We gather cost and throughput information from the synthesis and timing results and compare the cost and performance of our designs to those presented in other literatures. Our designs achieve a throughput of 3.2 Gbps with a 50 MHz clock and our cost triples from DES to TDES

Decorrelation: A Theory for Block Cipher Security

Pseudorandomness is a classical model for the security of block ciphers. In this paper we propose convenient tools in order to study it in connection with the Shannon Theory, the Carter-Wegman universal hash functions paradigm, and the Luby-Rackoff approach. This enables the construction of new ciphers with security proofs under specific models. We show how to ensure security against basic differential and linear cryptanalysis and even more general attacks. We propose practical construction scheme

A Chaos-Based Authenticated Cipher with Associated Data

In recent years, there has been a rising interest in authenticated encryptionwith associated data (AEAD)which combines encryption and authentication into a unified scheme. AEAD schemes provide authentication for a message that is divided into two parts: associated data which is not encrypted and the plaintext which is encrypted. However, there is a lack of chaos-based AEAD schemes in recent literature. This paper introduces a new128-bit chaos-based AEAD scheme based on the single-key Even-Mansour and Type-II generalized Feistel structure. The proposed scheme provides both privacy and authentication in a single-pass using only one 128-bit secret key. The chaotic tent map is used to generate whitening keys for the Even-Mansour construction, round keys, and random s-boxes for the Feistel round function. In addition, the proposed AEAD scheme can be implemented with true randomnumber generators to map a message tomultiple possible ciphertexts in a nondeterministic manner. Security and statistical evaluation indicate that the proposed scheme is highly secure for both the ciphertext and the authentication tag. Furthermore, it has multiple advantages over AES-GCM which is the current standard for authenticated encryption

Critical Analysis of Various Symmetric Key Cryptographic Algorithms

Current era is digital and has elite advancement in technology, almost in every field things are becoming technology friendly. It is the need to provide security to sensitive information in this fast growing technical world. Cryptography is one of the very popular fields of network security that deals with conversion of sensitive data into one which could not be understood by anyone without the secret key. Many researchers has worked in the area of cryptography and developed many algorithms in different period and providing security to the travelling data. It is need to know the strengths and weakness of each algorithm before using and suggesting to anybody to use one. After critically analyzing existing standard cryptographic algorithms on parameters like throughput, power consumption and memory usage on DES, TDES, AES, Blowfish, Twofish, Threefish, RC2, RC4, RC5 and RC6, it has been concluded that which algorithm will suit in which situation. DOI: 10.17762/ijritcc2321-8169.150616