1,434 research outputs found
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No full textTo show various forms of equivalence between programs Correctness of optimization � p opt ∼ p unopt: τ Secrecy as non-interference � p v ∼ p w: τ for v ≠ w Correspondence between CPS and direct style � p CPS ∼ p DS: τ This Talk Logical relations for wider range of programming constructs Perfect encryption [Sumii-Pierce 01] Cf. Type abstraction [Reynolds 83] Higher-order references [ongoing work] First-class channels [ongoing work] Everything is syntactic and operationa
Keys under doormats - mandating insecurity by requiring government access to all data and communications
No full textAbstract
Twenty years ago, law enforcement organizations lobbied to require data and communication services to engineer their products to guarantee law enforcement access to all data. After lengthy debate and vigorous predictions of enforcement channels “going dark,” these attempts to regulate the emerging Internet were abandoned. In the intervening years, innovation on the Internet flourished, and law enforcement agencies found new and more effective means of accessing vastly larger quantities of data. Today we are again hearing calls for regulation to mandate the provision of exceptional access mechanisms. In this report, a group of computer scientists and security experts, many of whom participated in a 1997 study of these same topics, has convened to explore the likely effects of imposing extraordinary access mandates.
We have found that the damage that could be caused by law enforcement exceptional access requirements would be even greater today than it would have been 20 years ago. In the wake of the growing economic and social cost of the fundamental insecurity of today’s Internet environment, any proposals that alter the security dynamics online should be approached with caution. Exceptional access would force Internet system developers to reverse “forward secrecy” design practices that seek to minimize the impact on user privacy when systems are breached.
The complexity of today’s Internet environment, with millions of apps and globally connected services, means that new law enforcement requirements are likely to introduce unanticipated, hard to detect security flaws. Beyond these and other technical vulnerabilities, the prospect of globally deployed exceptional access systems raises difficult problems about how such an environment would be governed and how to ensure that such systems would respect human rights and the rule of law
On the perfect encryption assumption
No full textNearly all models proposed within the scope of the study of security protocols make perfect encryption assumptions
On the perfect encryption assumption
No full textNearly all models proposed within the scope of the study of security protocols make perfect encryption assumptions. These hypotheses can be summarised as follow:- The decryption key must be known in order to extract the plaintext corresponding to a given ciphertext.- There is enough redundancy in the cryptosystem that a ciphertext can only be generated using encryption with the appropriate key and message. This assumption is obviously not true in practice. A first example is the one of the cryptosystems proceeding by cipher-block-chaining (CBC). In such systems, the encryption of message block sequence P1P2…Pn is C0C1C2…Cn where C0=I (Initialisation bloc) and Ci={Ci-1⊕Pi}K. It can be noticed that they present the following interesting particularity: If C0C1C2…CiCi+1…Cn = {P1P2…PiPi+1…Pn}K Then C0C1C2…Ci = {P1P2…Pi}K This property can be exploited (see [Boy90] or [SG92] for other instances) to flaw the Needham-Schroeder symmetric key authentication protocol [NS78]. This protocol intends to permit Alice to establish a shared secret key Kab with Bob and to obtain mutual conviction of the possession of the key by each other. The key is provided by a trusted server S who shares the secret keys Kas and Kbs with A and B respectively. This protocol can be described as follow
Breaking the GSM A5/1 Cryptography Algorithm with Rainbow Tables and High-End FPGAs
No full textA5 is the basic cryptographic algorithm used in GSM cell-phones to ensure that the user communication is protected against illicit acts. The A5/1 version was developed in 1987 and has since been under attack. The most recent attack on A5/1 is the “A51 security project”, led by Karsten Nohl that consists of the creation of rainbow tables that map the internal state of the algorithm with the keystream. Rainbow tables are efficient structures that allow the tradeoff between run-time (computations performed to crack a conversation) and space (memory to hold pre-computed information). In this paper we describe a very effective parallel architecture for the creation of the A5/1 rainbow tables in reconfigurable hardware. Rainbow table creation is the most expensive portion of cracking a particular encrypted information exchange. Our approach achieves almost 3000x speedup over a single processor, and 2.5x speedup compared to GPUs. This performance is achieved with less than 5 Watt power consumption, achieving an energy efficiency in the order of 150x better that the GPU approach
ID-Based Self-encryption via Hyperledger Fabric Based Smart Contract
No full textThis paper offers a prototype of a Hyperledger Fabric-IPFS based network architecture including a smart contract based encryption scheme that meant to improve the security of user’s data that is being uploaded to the distributed ledger. A new extension to the self-encryption scheme was deployed by integrating data owner’s identity into the encryption process. Such integration allows to permanently preserve ownership of the original file and link it to the person/entity who originally uploaded it. Moreover, self-encryption provides strong security guarantees that decryption of a file is computationally not feasible under the condition that the encrypted file and the key are safely stored.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Cyber Securit
Multi-Locking and Perfect Argument Order: Two Major Improvements of Attribute-Based Encryption~(Long Paper)
No full textAttribute Based Encryption, proposed by Sahai and Waters in 2007, is a set of promising cryptographic schemes that enable various fine grained access control on encrypted data. With a unique encryption key, a user is able to encrypt data for a very specific group of recipient that matches a set of attributes contained inside their decryption key.
In current scenario where personal devices share an increasing volume of private data on the web, such encryption algorithms are more than ever a strong alternative to standard encryption algorithms.
In this paper, we propose two major improvements of ABE namely the Perfect Argument Order Optimization and the Multi-Locking. Multi-Locking ABE is an extension of ABE that enables to share access control policy on an arbitrary number of entities. We also make a step further for the speed-up of ABE by providing the ``Perfect Argument Order Optimization\u27\u27, which is a generalization of the ``Fixed Argument Optimization\u27\u27 of Scott et al. to a much wider range of ABE constructions (and in particular to our Multi-Locking ABE).
Based on those two improvements we propose a construction of the first privacy-preserving Cloud service based on ABE, allowing ephemeral accesses to the data.
The Multi-Locking ABE and the Perfect Argument Order Optimization have been successfully integrated to the OpenABE library, providing a speed-up for a variety of ABE constructions
MODIFICATION ADVANCED ENCRYPTION STANDARD (AES) ALGORITHM WITH PERFECT STRICT AVALANCHE CRITERION S-BOX
No full textThe Advanced Encryption Standard or better known as the AES Algorithm is a standard algorithm and has been widely used as an application of cryptography. Currently, a lot of research is developing about attacks on the AES algorithm. Therefore, there have been many studies related to modifications to the AES algorithm with the aim of increasing the security of the algorithm and to produce alternatives to encryption algorithms that can be used to secure data. In this study, modifications were made to the AES algorithm by replacing the S-box using the perfect SAC S-box in the SubBytes process. The Perfect SAC S-box has an exact SAC average value of 0.5. The S-box that will be used must have good security strength, therefore the perfect SAC S-box is tested, namely the AC, SAC, BIC, XOR Table Distribution, and LAT Distribution tests. Based on the results of the study, it was found that the perfect SAC S-box had almost the same S-box test results as the AES S-box. Furthermore, after the perfect SAC S-box is applied to the AES algorithm, it is analyzed how the effect of these modifications on the AES algorithm uses randomness testing for the block cipher algorithm, namely the strict avalanche criterion (SAC) test. The results of the AES test with perfect SAC S-box can meet the SAC test since the second round with better results than the original AES algorithm with SAC values of 0.5003 and 0.5019
Encryption Possessing - Statistical Perfect Secrecy and Stealth
No full textthis report we have presented a novel methodof encryption whose kernel is based on a solution to a problem which has been reported open, namely the Distribution Optimizing Data Encoding (DODE) problem. The invention atistical Perfect S crecy -a property which is closely related to the phenomenon of Perf ect Secrecy. The invention utilizes the DODE solution to yield a stream cipherf or which the output resembles random noise evenf or relatively small keys. The Statistical Perf ect Secrecy phenomenon is not merely experimentally verifiedfr all the FIPS 140 tests on the standard benchmark corpuses, but also f0fijjvV and rigorously proven. The resulting cryptosystem also demonstrates bit-wise, key-to-output, and input-output independence on the standard benchmark corpuse
Generating tightly focused perfect optical vortex for ultra-secure optical encryption
No full textLight's orbital angular momentum (OAM) with inherent mode orthogonality has been suggested as a new way to the optical encryption. However, the dependence of annular intensity profiles on the topological charge complicates nanoscale light-matter interactions and hampers the ultra-secure encryption application. In this paper, we demonstrate ultra-secure image encryption by tightly focusing perfect optical vortex (POV) beams with controllable annular intensity profiles and OAM states. A simple scheme composed of single spatial light modulator is proposed to generate radius-controllable POV in tightly focused beams. Such focused POV beams with identical intensity profiles but varied OAM states are applied to disorder-coupled gold nanorod aggregates to selectively excite electromagnetic hot spots for encoding information through photothermal deformation. As such, ultra-secure image encryption in OAM states of POV beams in combination with different polarizations can be achieved. Our results lay the ground for diverse nanophotonic applications harnessing the OAM division of POV beams
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