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Nils Gura

Bio: Nils Gura is an academic researcher from Oracle Corporation. The author has contributed to research in topics: Elliptic curve point multiplication & Crossover switch. The author has an hindex of 12, co-authored 19 publications receiving 2528 citations. Previous affiliations of Nils Gura include Business International Corporation & Sun Microsystems Laboratories.

Papers
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Journal Article
TL;DR: In this paper, an Atmel ATmega128 at 8 MHz was used to implement ECC point multiplication over fields using pseudo-Mersenne primes as standardized by NIST and SECG.
Abstract: Strong public-key cryptography is often considered to be too computationally expensive for small devices if not accelerated by cryptographic hardware. We revisited this statement and implemented elliptic curve point multiplication for 160-bit, 192-bit, and 224-bit NIST/SECG curves over GF(p) and RSA-1024 and RSA-2048 on two 8-bit microcontrollers. To accelerate multiple-precision multiplication, we propose a new algorithm to reduce the number of memory accesses. Implementation and analysis led to three observations: 1. Public-key cryptography is viable on small devices without hardware acceleration. On an Atmel ATmega128 at 8 MHz we measured 0.81s for 160-bit ECC point multiplication and 0.43s for a RSA-1024 operation with exponent e = 2 16 +1. 2. The relative performance advantage of ECC point multiplication over RSA modular exponentiation increases with the decrease in processor word size and the increase in key size. 3. Elliptic curves over fields using pseudo-Mersenne primes as standardized by NIST and SECG allow for high performance implementations and show no performance disadvantage over optimal extension fields or prime fields selected specifically for a particular processor architecture.

1,113 citations

Book ChapterDOI
11 Aug 2004
TL;DR: To accelerate multiple-precision multiplication, a new algorithm to reduce the number of memory accesses is proposed and implemented elliptic curve point multiplication for 160-bit, 192- bit, and 224-bit NIST/SECG curves over GF(p), RSA-1024 and RSA-2048 on two 8-bit microcontrollers.
Abstract: Strong public-key cryptography is often considered to be too computationally expensive for small devices if not accelerated by cryptographic hardware. We revisited this statement and implemented elliptic curve point multiplication for 160-bit, 192-bit, and 224-bit NIST/SECG curves over GF(p) and RSA-1024 and RSA-2048 on two 8-bit microcontrollers. To accelerate multiple-precision multiplication, we propose a new algorithm to reduce the number of memory accesses.

1,081 citations

Proceedings Article
01 Jan 2004
TL;DR: The results show that an Apache web server can handle 11%-31% more HTTPS requests per second when using ECC rather than RSA at short-term security levels, and at security levels necessary to protect data beyond 2010, the use of ECC over RSA improves server performance by 110%-279% under realistic workloads.
Abstract: Elliptic Curve Cryptography (ECC) is emerging as an attractive alternative to traditional public-key cryptosystems (RSA, DSA, DH). ECC offers equivalent security with smaller key sizes resulting in faster computations, lower power consumption, as well as memory and bandwidth savings. While these characteristics make ECC especially appealing for mobile devices, they can also alleviate the computational burden on secure web servers. This article studies the performance impact of using ECC with Secure Sockets Layer (SSL), the dominant Internet security protocol. We benchmark the Apache web server with an ECC-enhanced version of OpenSSL under a variety of conditions. Our results show that an Apache web server can handle 11%-31% more HTTPS requests per second when using ECC rather than RSA at short-term security levels. At security levels necessary to protect data beyond 2010, the use of ECC over RSA improves server performance by 110%-279% under realistic workloads.

80 citations

Patent
04 Mar 2005
TL;DR: In this paper, a secure end-to-end connection between a remote device having a wireless link and a control/monitoring location for the remote device through a gateway is established.
Abstract: A secure end to end connection is established between a remote device having a wireless link and a control/monitoring location for the remote device through a gateway. During the establishing of the secure connection, a compressed message representation is used to communicate between the gateway and the remote device over the wireless link and an uncompressed message representation is used to communicate between the gateway and the first location. The establishment of the secure connection utilizes public-key algorithms.

74 citations

Patent
26 Aug 2013
TL;DR: In this paper, a hardware circuitry may evaluate minimal perfect hash functions mapping keys to addresses in lookup tables, including a primary hash function sub-circuit that applies linear hash functions to input key values (using carry-free arithmetic) to produce primary hash values.
Abstract: Hardware circuitry may evaluate minimal perfect hash functions mapping keys to addresses in lookup tables. The circuitry may include primary hash function sub-circuits that apply linear hash functions to input key values (using carry-free arithmetic) to produce primary hash values. Each sub-circuit may multiply bit vectors representing key values by a bit matrix and add a constant bit vector to the result. The circuitry may include a secondary hash function sub-circuit that generates secondary hash values by aggregating values associated with multiple primary hash values using signed, unsigned, or modular integer addition, or bit-wise XOR operations. Secondary hash values may be usable to access data values in the lookup table that are associated with particular input key values. The circuitry may determine the validity of input keys and may alter the configuration or contents of the lookup tables. The hash function sub-circuits may include programmable hash tables.

40 citations


Cited by
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Proceedings ArticleDOI
22 Apr 2008
TL;DR: TinyECC is presented, a ready-to-use, publicly available software package for ECC-based PKC operations that can be flexibly configured and integrated into sensor network applications and shows the impacts of individual optimizations on the execution time and resource consumptions.
Abstract: Public key cryptography (PKC) has been the enabling technology underlying many security services and protocols in traditional networks such as the Internet. In the context of wireless sensor networks, elliptic curve cryptography (ECC), one of the most efficient types of PKC, is being investigated to provide PKC support in sensor network applications so that the existing PKC-based solutions can be exploited. This paper presents the design, implementation, and evaluation of TinyECC, a configurable library for ECC operations in wireless sensor networks. The primary objective of TinyECC is to provide a ready-to-use, publicly available software package for ECC-based PKC operations that can be flexibly configured and integrated into sensor network applications. TinyECC provides a number of optimization switches, which can turn specific optimizations on or off based on developers' needs. Different combinations of the optimizations have different execution time and resource consumptions, giving developers great flexibility in integrating TinyECC into sensor network applications. This paper also reports the experimental evaluation of TinyECC on several common sensor platforms, including MICAz, Tmote Sky, and Imotel. The evaluation results show the impacts of individual optimizations on the execution time and resource consumptions, and give the most computationally efficient and the most storage efficient configuration of TinyECC.

966 citations

Journal ArticleDOI
TL;DR: This article outlines the constraints, security requirements, and attacks with their corresponding countermeasures in WSNs, and presents a holistic view of security issues, classified into five categories: cryptography, key management, secure routing, secure data aggregation, and intrusion detection.
Abstract: Wireless Sensor Networks (WSNs) are used in many applications in military, ecological, and health-related areas These applications often include the monitoring of sensitive information such as enemy movement on the battlefield or the location of personnel in a building Security is therefore important in WSNs However, WSNs suffer from many constraints, including low computation capability, small memory, limited energy resources, susceptibility to physical capture, and the use of insecure wireless communication channels These constraints make security in WSNs a challenge In this article we present a survey of security issues in WSNs First we outline the constraints, security requirements, and attacks with their corresponding countermeasures in WSNs We then present a holistic view of security issues These issues are classified into five categories: cryptography, key management, secure routing, secure data aggregation, and intrusion detection Along the way we highlight the advantages and disadvantages of various WSN security protocols and further compare and evaluate these protocols based on each of these five categories We also point out the open research issues in each subarea and conclude with possible future research directions on security in WSNs

929 citations

Proceedings ArticleDOI
08 Mar 2005
TL;DR: Measurements on an Atmel ATmega128L low-power microcontroller platform indicate that public-key cryptography is very viable on 8-bit energy-constrained platforms even if implemented in software.
Abstract: In this paper, we quantify the energy cost of authentication and key exchange based on public-key cryptography on an 8-bit microcontroller platform. We present a comparison of two public-key algorithms, RSA and elliptic curve cryptography (ECC), and consider mutual authentication and key exchange between two untrusted parties such as two nodes in a wireless sensor network. Our measurements on an Atmel ATmega128L low-power microcontroller indicate that public-key cryptography is very viable on 8-bit energy-constrained platforms even if implemented in software. We found ECC to have a significant advantage over RSA as it reduces computation time and also the amount of data transmitted and stored.

846 citations

Proceedings ArticleDOI
02 Nov 2005
TL;DR: The experiences with developing a combined hardware and software platform for medical sensor networks, called CodeBlue, which provides protocols for device discovery and publish/subscribe multihop routing, as well as a simple query interface that is tailored for medical monitoring are described.
Abstract: Sensor networks have the potential to greatly impact many aspects of medical care. By outfitting patients with wireless, wearable vital sign sensors, collecting detailed real-time data on physiological status can be greatly simplified. However, there is a significant gap between existing sensor network systems and the needs of medical care. In particular, medical sensor networks must support multicast routing topologies, node mobility, a wide range of data rates and high degrees of reliability, and security. This paper describes our experiences with developing a combined hardware and software platform for medical sensor networks, called CodeBlue. CodeBlue provides protocols for device discovery and publish/subscribe multihop routing, as well as a simple query interface that is tailored for medical monitoring. We have developed several medical sensors based on the popular MicaZ and Telos mote designs, including a pulse oximeter, EKG and motion-activity sensor. We also describe a new, miniaturized sensor mote designed for medical use. We present initial results for the CodeBlue prototype demonstrating the integration of our medical sensors with the publish/subscribe routing substrate. We have experimentally validated the prototype on our 30-node sensor network testbed, demonstrating its scalability and robustness as the number of simultaneous queries, data rates, and transmitting sensors are varied. We also study the effect of node mobility, fairness across multiple simultaneous paths, and patterns of packet loss, confirming the system’s ability to maintain stable routes despite variations in node location and

761 citations