Human Public-Key Encryption

This paper proposes a public-key cryptosystem and a short password encryption mode, where traditional hardness assumptions are replaced by specific refinements of the CAPTCHA concept called Decisional and Existential CAPTCHAs. The public-key encryption method, achieving 128-bit security, typically requires from the sender to solve one CAPTCHA. The receiver does not need to resort to any human aid. A second symmetric encryption method allows to encrypt messages using very short passwords shared between the sender and the receiver. Here, a simple 5-character alphanumeric password provides sufficient security for all practical purposes. We conjecture that the automatic construction of Decisional and Existential CAPTCHAs is possible and provide candidate ideas for their implementation

Encryption’s Importance to Economic and Infrastructure Security

Det övergripande syftet med den här avhandlingen var att utreda om network coopetition, samarbete mellan konkurrerande aktörer, kan öka värdeskapandet inom hälso- och sjukvården. Inom hälso- och sjukvården är network coopetition ett ämne som fått liten uppmärksamhet i tidigare studier. För att besvara syftet utvecklades en modell för network coopetition inom hälso- och sjukvården. Modellen applicerades sedan på en del av vårdkedjan för patienter i behov av neurokirurgisk vård. Resultaten från avhandlingen visar att: (1) Förutsättningarna för network coopetition i vårdkedjan för patienter i behov av neurokirurgisk vård är uppfyllda. (2) Det finns exempel på horisontell network coopetition i den studerade vårdkedjan. (3) Det existerar en diskrepans mellan hur aktörerna  ser  på  sitt  eget  och  de  andra  aktörernas  värdeskapande. (4)  Värdeskapandet bör utvärderas som ett gemensamt system där hänsyn tas till alla aktörer och utvärderas på process- nivå där hänsyn tas till alla intressenter. Dessa resultat leder fram till den övergripande slutsatsen är att network coopetition bör kunna öka värdeskapandet för högspecialiserade vårdkedjor med en stor andel inomlänspatienter.The overall purpose of this thesis was to investigate whether network coopetition, cooperation between competitive actors, can increase the value creation within the health care system. Within health care, network coopetition is a subject granted little attention in previous research. To fulfil the purpose a model for network coopetition within the health care system was developed. The model was the applied to one part of the chain of care for patients in need of neurosurgery. The results from this thesis show: (1) The conditions for network coopetition in the chain of care for patients in need of neurosurgery are fulfilled. (2) Examples of horizontal network coopetition have been found in the studied chain of care. (3) There is an existing discrepancy between how each actor recognizes its own and the other actors’ value creation. (4) The value creation ought to be evaluated as a common system where all actors are taken into account and at a process level where all stakeholders are considered. These results supports the final conclusion that network coopetition ought to be able to increase the value creation for highly specialized chain of cares with a large share of within-county patients

Review on DNA Cryptography

Cryptography is the science that secures data and communication over the network by applying mathematics and logic to design strong encryption methods. In the modern era of e-business and e-commerce the protection of confidentiality, integrity and availability (CIA triad) of stored information as well as of transmitted data is very crucial. DNA molecules, having the capacity to store, process and transmit information, inspires the idea of DNA cryptography. This combination of the chemical characteristics of biological DNA sequences and classical cryptography ensures the non-vulnerable transmission of data. In this paper we have reviewed the present state of art of DNA cryptography.Comment: 31 pages, 12 figures, 6 table

Towards Enhanced Usability of IT Security Mechanisms - How to Design Usable IT Security Mechanisms Using the Example of Email Encryption

Nowadays, advanced security mechanisms exist to protect data, systems, and networks. Most of these mechanisms are effective, and security experts can handle them to achieve a sufficient level of security for any given system. However, most of these systems have not been designed with focus on good usability for the average end user. Today, the average end user often struggles with understanding and using security mecha-nisms. Other security mechanisms are simply annoying for end users. As the overall security of any system is only as strong as the weakest link in this system, bad usability of IT security mechanisms may result in operating errors, resulting in inse-cure systems. Buying decisions of end users may be affected by the usability of security mechanisms. Hence, software provid-ers may decide to better have no security mechanism then one with a bad usability. Usability of IT security mechanisms is one of the most underestimated properties of applications and sys-tems. Even IT security itself is often only an afterthought. Hence, usability of security mechanisms is often the after-thought of an afterthought. This paper presents some guide-lines that should help software developers to improve end user usability of security-related mechanisms, and analyzes com-mon applications based on these guidelines. Based on these guidelines, the usability of email encryption is analyzed and an email encryption solution with increased usability is presented. The approach is based on an automated key and trust man-agement. The compliance of the proposed email encryption solution with the presented guidelines for usable security mechanisms is evaluated

Identity-based encryption with hierarchical key-insulation in the standard model

A key exposure problem is unavoidable since it seems human error can never be eliminated completely, and key-insulated encryption is one of the cryptographic solutions to the problem. At Asiacrypt\u2705, Hanaoka et al. introduced hierarchical key-insulation functionality, which is attractive functionality that enhances key exposure resistance, and proposed an identity-based hierarchical key-insulated encryption (hierarchical IKE) scheme in the random oracle model. In this paper, we first propose the hierarchical IKE scheme in the standard model (i.e., without random oracles). Our hierarchical IKE scheme is secure under the symmetric external Diffie–Hellman (SXDH) assumption, which is a static assumption. Particularly, in the non-hierarchical case, our construction is the first IKE scheme that achieves constant-size parameters including public parameters, secret keys, and ciphertexts. Furthermore, we also propose the first public-key-based key-insulated encryption (PK-KIE) in the hierarchical setting by using our technique

On Using Encryption Techniques to Enhance Sticky Policies Enforcement

How to enforce privacy policies to protect sensitive personal data has become an urgent research topic for security researchers, as very little has been done in this field apart from some ad hoc research efforts. The sticky policy paradigm, proposed by Karjoth, Schunter, and Waidner, provides very useful inspiration on how we can protect sensitive personal data, but the enforcement is very weak. In this paper we provide an overview of the state of the art in enforcing sticky policies, especially the concept of sticky policy enforcement using encryption techniques including Public-Key Encryption (PKE), Identity-Based Encryption (IBE), Attribute-Based Encryption (ABE), and Proxy Re-Encryption (PRE). We provide detailed comparison results on the (dis)advantages of these enforcement mechanisms. As a result of the analysis, we provide a general framework for enhancing sticky policy enforcement using Type-based PRE (TPRE), which is an extension of general PRE