A Survey on Homomorphic Encryption Schemes: Theory and Implementation

Legacy encryption systems depend on sharing a key (public or private) among the peers involved in exchanging an encrypted message. However, this approach poses privacy concerns. Especially with popular cloud services, the control over the privacy of the sensitive data is lost. Even when the keys are not shared, the encrypted material is shared with a third party that does not necessarily need to access the content. Moreover, untrusted servers, providers, and cloud operators can keep identifying elements of users long after users end the relationship with the services. Indeed, Homomorphic Encryption (HE), a special kind of encryption scheme, can address these concerns as it allows any third party to operate on the encrypted data without decrypting it in advance. Although this extremely useful feature of the HE scheme has been known for over 30 years, the first plausible and achievable Fully Homomorphic Encryption (FHE) scheme, which allows any computable function to perform on the encrypted data, was introduced by Craig Gentry in 2009. Even though this was a major achievement, different implementations so far demonstrated that FHE still needs to be improved significantly to be practical on every platform. First, we present the basics of HE and the details of the well-known Partially Homomorphic Encryption (PHE) and Somewhat Homomorphic Encryption (SWHE), which are important pillars of achieving FHE. Then, the main FHE families, which have become the base for the other follow-up FHE schemes are presented. Furthermore, the implementations and recent improvements in Gentry-type FHE schemes are also surveyed. Finally, further research directions are discussed. This survey is intended to give a clear knowledge and foundation to researchers and practitioners interested in knowing, applying, as well as extending the state of the art HE, PHE, SWHE, and FHE systems.Comment: - Updated. (October 6, 2017) - This paper is an early draft of the survey that is being submitted to ACM CSUR and has been uploaded to arXiv for feedback from stakeholder

Mental Card Gaming Protocols Supportive Of Gameplay Versatility, Robustness And Efficiency

Pennainan kad mental merupakan protokol kriptografi yang membolehkan pennainan yang ~ disahkan adil di kalangan parti-parti jauh yang penyangsi dan berpotensi menipu. Pennainan kad ini setidak-tidaknya patut menyokong-tanpa memperkenal~an parti ketiga yang dipercayai (TTP)--rahsia kad, pengesanan penipuan dan keselamatan bersyarat ke atas pakatan pemain. Tambahan kepada keperJuan asas ini, kami meninjau isu-isu pennainan kad mental yang berkaitan dengan fungsian permainan, keteguhan operasional dan kecekapan implementasi. Pengkajian kami diberangsang oleh potensi pennainan berasaskan komputer dan rangkaian yang melewati batas kemampuan kad fizikal, terutamanya pembongkaran maklumat terperinci kad (seperti warna, darjat, simbol atau kebangsawanan) sambil merahsiakan nilai keseluruhan kad tersebut. ~. Mental card games are cryptographic protocols which permit verifiably fair gameplay among a l< ~. priori distrustful and potentially untrustworthy remote parties and should minimally providewithout the introduction of a trusted third party (TTP)---for card confidentiality, fraud detection and conditional security against collusion. In addition to these basic requirements, we explore into gameplay functionality, operational robustness and implementation efficiency issues of mental card gaming. Our research is incited by the potential of computer-based and networkmediated gameplay beyond the capability of physical cards, particularly fine-grained information disclosure (such as colour, rank, symbol or courtliness) with preservation of card secrecy. On the other hand, being network connected renders the protocol susceptible to (accidental or intentional) disconnection attack, as well as other malicious behaviours

Some Implementation Issues for Security Services based on IBE

Identity Based Encryption (IBE) is a public key cryptosystem where a unique identity string, such as an e-mail address, can be used as a public key. IBE is simpler than the traditional PKI since certificates are not needed. An IBE scheme is usually based on pairing of discrete points on elliptic curves. An IBE scheme can also be based on quadratic residuosity. This paper presents an overview of these IBE schemes and surveys present IBE based security services. Private key management is described in detail with protocols to authenticate users of Private Key Generation Authorities (PKG), to protect submission of generated private keys, and to avoid the key escrow problem. In the security service survey IBE implementations for smartcards, for smart phones, for security services in mobile networking, for security services in health care information systems, for secure web services, and for grid network security are presented. Also the performance of IBE schemes is estimated

Symmetric private information retrieval via additive homomorphic probabilistic encryption

Suppose there is a movie you would be interested in watching via pay-per-view, but you refuse to purchase the feed because you believe that the supplier will sell your information to groups paying for the contact information of all the people who purchased that movie, and the association of your name to that purchase could hinder career, relationships, or increase the amount of time you spend cleaning SPAM out of your mailbox. Private Information Retrieval (PIR) will allow you to retrieve a particular feed without the supplier knowing which feed you actually got, and Symmetric Private Information Retrieval (SPIR) will assure the supplier, if the feeds are equally priced, that you received only the number of feeds you purchased. Now you can purchase without risking your name being associated with a particular feed and the supplier has gained the business of a once paranoid client. The problem of SPIR can be achieved with the cryptographic primitive Oblivious Transfer (OT). Several approaches to constructing such protocols have been posed and proven to be secure. Most attempts have aimed at reducing the amount of communication, theoretically, but this thesis compares the computational expense of the algorithms through experimentation to show that reduction of communication is less valuable in the effort of achieving a practical protocol than reducing the amount of computation. Further, this thesis introduces new protocols to compete with previous published protocols that derive security from additive homomorphic probabilistic encryption schemes, and explores means to increase the length of data handled by these protocols so that the media is more useful and the time to complete the protocol is reasonable

Fast Keyword Search With Encryption

Paillier� Method is used in research and cloud protected outsourcing as well as privacy-preserving computation. In this paper we implement Pallier Method for providing security. Fast Keyword Search Perform on encrypted Data not directly on plain text, hence Security is given to database. In Multi-writer scenario Data sources upload Data on Different Resources .Data owner is responsible for generating tokens and encrypt data. Data owner and query source perform queries through a query processor. Data originated by data sources in which personal data and public data include, personal data search only authorized personal and public data search anyone who create their data source registration successfully. Cipher text length is created in between 16 digits to 256 digits, if data source search similar data on multiple time then every time query is encrypted using different numbers. Data in database stored using number of attribute. We focused on security in Pallier method