Nuggets tagged cryptography - [remove filter]

Sept. 10, 2016 (9 months, 2 weeks ago)

Okayama University reveals first flexible cryptoprocessor

Researchers at Okayama University have collaborated with Tokyo Electron Device to create a cryptography chip that can adjust its level of security on the fly - a secure cryptoprocessor that can change the scale of security without requiring changes in the hardware. As computer performance improves, it will become increasingly difficult to adjust the security level of devices to match emerging techniques and use new schemes. For example the secure key length of RSA cryptography can be 512, 1024, 2048, and 3072 bits. The processor also supports recent advances in cryptography like elliptic curve and paring-based cryptography. Cryptoprocessors need to be upgraded together with their arithmetic architectures. The new cryptoprocessor scales with evolving security needs using a cyclic vector multiplication algorithm (CVMA), a concept previously developed at Okayama. The chip has a compact circuit scale, and could be used in terminals and IoT devices.

Sept. 6, 2016 (9 months, 3 weeks ago)

Bitcoin and Cryptocurrency Technologies: A Comprehensive Introduction | RSA Conference

Noted Bitcoin experts have produced a highly technical resource that is a comprehensive introduction to Bitcoin. The authors explain in technical detail how the underlying Bitcoin protocol and technology operates. Bitcoin also has a number of technical and security limitations which are also discussed. One of the more significant limitations is that the cryptographic algorithms in Bitcoin are hardcoded and fixed within in the protocol. If the underlying cryptography in Bitcoin is one day broken the logical solution would be to change the protocols, but the authors go into a detailed technical overview of why this is not feasible.

Feb. 24, 2016 (1 year, 4 months ago)

Byzcoin - Bitcoin protocol improvements for low latency transactions

Bitcoin is a decentralized cryptocurrency providing an open, self-regulating alternative to classical currencies. Bitcoin uses a peer-to-peer network where users submit transactions without intermediaries. Bitcoin miners collect transactions, solve computational puzzles (proof-of-work) to reach consensus, and add the transactions to a distributed public ledger known as the blockchain. The original Bitcoin paper argues that transaction processing is secure and irreversible as long as the largest colluding group of miners represents less than 50% of total computing capacity and at least about one hour has elapsed. Critically this transaction latency limits Bitcoin's suitability for real-time transactions, furthermore recent work has exposed vulnerabilities to transaction reversibility, double-spending, and strategic mining attacks. This paper introduces ByzCoin, a novel protocol that leverages scalable collective signing to commit Bitcoin transactions irreversibly within seconds.

Jan. 30, 2015 (2 years, 4 months ago)

Bitcoin Startup Gem May Revolutionize MultiSig Wallet Security

Bitcoin startup Gem provides a scalable API for bitcoin developers, has a new security enhancement that may be significant for the future of Bitcoin security. The company announced the inclusion of Custom Hardware Security Modules produced by Thales e-Security, as part of their standard multi-sig bitcoin wallet. Multi-sig wallets have become the standard for Bitcoin wallet security. A multi-sig wallet is associated with several private keys, making it more secure.

Nov. 17, 2014 (2 years, 7 months ago)

The Decrits Consensus Algorithm - The New Bitcoin?

This non peer reviewed paper claims to progress the state of the art in cryptocurrency. Cryptocurrencies, such as Bitcoin, are digital versions of money protected from duplication and fraud by cryptography. Bitcoin uses the concept of Proof of Work (POW) to ensure the validity of the bitcoins. In essence the bitcoin owner has to perform a complex calculation to realise the money. However at lesst one weakness of bitcoin has been published, and transactions are time consuming and have some risk. This paper makes the claim that the Decrits Consensus Algorithm is superior to POW algorithms in many ways: faster transaction confirmations, truly irreversible transactions, and permanent punishments to malevolent actors - all at virtually no external capital cost. DCA is a Proof of Stake algorithm where the owner of some currency risks some of their currency to maintain the security and validity of the currency and their stake in it. At this time, the benefits of the DCA over other POS algorithms is not clear, indeed, the author of this paper is unaware of any papers describing Peercoin, Nxt, or other POS algorithm in enough detail to make a proper comparison with Decrits.This work shows that digital currency is still evolving and, despite the seeming enthusiasm for Bitcoin, more secure and usable cryptocurrencies are under development.

July 23, 2014 (2 years, 11 months ago)

Bitcoin mining - threat to security model

The Bitcoin cryptocurrency records its transactions in a public log called the blockchain. Its security depends on the distributed protocol that maintains the blockchain, run by participants called miners. Previously it was thought that the protocol was secure against colluding minority groups, i.e., it incentivizes miners to follow the protocol as prescribed. This paper presents an attack whereby colluding miners obtain revenue larger than their fair share. Rational miners would thus prefer to join the selfish miners, and the colluding group will increase in size until it becomes a majority. At this point, the Bitcoin system ceases to be a decentralized currency. Selfish mining is shown in this work to be feasible for any group size of colluding miners. The paper proposes a practical modification to the Bitcoin protocol that protects against selfish mining groups with less than 1/4 of the resources. Such result shows the need for extensive testing and protocol analysis of any cryptographic currency. Any, future flaw identified by cryptographic analysis can be a significant threat to the currency economics, but proving the security of such schemes is extremely difficult.

July 9, 2014 (2 years, 11 months ago)

Analysis of the RSA Algorithm using GPU programming

NVIDIA's Compute Unified Device Architecture (CUDA) platform provides a set of tools to write programs that make use of NVIDIA's GPUs. As massively-parallel hardware devices they can process large amounts of data simultaneously and significantly speedup suitable programs. By applying this approach to the widely-used RSA cryptographic protocol, a speedup is achieved but exact performance comparisons against commercial systems are unclear. This is an important area as the bottleneck for RSA lies in the data and key size. The use of small prime numbers is a security vulnerability but the use of large prime numbers slows the algorithm as computation effort increases.

April 10, 2014 (3 years, 2 months ago)

New encryption scheme is inspired by human biology

This new encryption technique is based on the coupling functions that model the interaction between the heart and lungs and allow them to be synchronised. This provides a dynamic system such that the data is encrypted at different times and only makes sense in the context of both sender and receiver. A patent has been filed but its degree of security now needs substantial mathematical evaluation via novel cryptanalysis.

Sept. 13, 2011 (5 years, 9 months ago)

Practical PIR for Electronic Commerce

Private information retrieval (PIR) provides a means of querying a database without the database being able to learn any information about the query. This papoer extends Goldberg's multi-server information-theoretic PIR with a suite of protocols for privacy preserving e-commerce. Symmetric private information retrieval (SPIR) adds an additional restriction to PIR that prevents the user from learning information about any records except for the one requested, thus addressing the need for simultaneous user and database privacy. The work has implemented an open source implementation of SPIR which implements tiered pricing, access control lists, multiple payees and 'best-seller' lists with proven security properties and scalability. The prototype implementations suggest that the protocols may be practical for deployment in real-world e-commerce applications

Sept. 12, 2011 (5 years, 9 months ago)

Anonymity and one-way authentication

Key agreement is an important cryptographic primitive that has been extensively studied, especially in the two-party mutually authenticated setting. However, only a few protocols have considered the problem of one-way authentication. There can be various reasons for clients to be unauthenticated. They may not require access to any resources that require authentication but are indifferent to anonymity, they wish very strongly to be anonymous. One way authentication is quite prevalent on the internet e.g. in the case of SSL credit card payments, and the paper presents a number of ways where one way authenticated key agreement has practical uses. The paper provides a formal model of possible security goals of such protocols. It is unclear as yet whether such models naturally lead to new and practical protocols