DOCSLIB.ORG

Encryption Is Futile: Delay Attacks on High-Precision Clock Synchronization 1

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Encryption Is Futile: Delay Attacks on High-Precision Clock Synchronization 1 R. ANNESSI, J. FABINI, F.IGLESIAS, AND T. ZSEBY: ENCRYPTION IS FUTILE: DELAY ATTACKS ON HIGH-PRECISION CLOCK SYNCHRONIZATION 1 Encryption is Futile: Delay Attacks on High-Precision Clock Synchronization Robert Annessi, Joachim Fabini, Felix Iglesias, and Tanja Zseby Institute of Telecommunications TU Wien, Austria Email: fi[email protected] Abstract—Clock synchronization has become essential to mod- endanger control decisions, and adversely affect the overall ern societies since many critical infrastructures depend on a functionality of a wide range of (critical) services that depend precise notion of time. This paper analyzes security aspects on accurate time. of high-precision clock synchronization protocols, particularly their alleged protection against delay attacks when clock syn- In recent years, security of clock synchronization received chronization traffic is encrypted using standard network security increased attention as various attacks on clock synchronization protocols such as IPsec, MACsec, or TLS. We use the Precision protocols (and countermeasures) were proposed. For this Time Protocol (PTP), the most widely used protocol for high- reason, clock synchronization protocols need to be secured precision clock synchronization, to demonstrate that statistical whenever used outside of fully trusted network environments. traffic analysis can identify properties that support selective message delay attacks even for encrypted traffic. We furthermore Clock synchronization protocols are specifically susceptible to identify a fundamental conflict in secure clock synchronization delay attacks since the times when messages are sent and between the need of deterministic traffic to improve precision and received have an actual effect on the receiver’s notion of the need to obfuscate traffic in order to mitigate delay attacks. time. Delay attacks specifically can degrade the precision of A theoretical analysis of clock synchronization protocols iso- clock synchronization such that applications depending on it lates the characteristics that make these protocols vulnerable to delay attacks and argues that such attacks cannot be prevented may malfunction. Such malfunctioning is endangering critical entirely but only be mitigated. Knowledge of the underlying com- infrastructures that increasingly depend on a precise notion of munication network in terms of one-way delays and knowledge time. on physical constraints of these networks can help to compute Encrypting and signing clock synchronization messages guaranteed maximum bounds for slave clock offsets. These (with IPsec [7], MACsec [8], or TLS [9]) is commonly bounds are essential for detecting delay attacks and minimizing their impact. In the general case, however, the precision that recommended in order to provide security against a wealth of can be guaranteed in adversarial settings is orders of magnitude network-based attacks. In this paper, we show that encryption lower than required for high-precision clock synchronization in alone cannot provide sufficient security against delay attacks critical infrastructures, which, therefore, must not rely on a on high-precision clock synchronization, which highlights precise notion of time when using untrusted networks. the insecurity of numerous applications (including critical infrastructures) that depend on a precise notion of time. We present a fundamental limitation of clock synchronization over I. INTRODUCTION untrusted networks that is independent of the actual clock LOCK synchronization protocols have become an es- synchronization protocol and communication network and even C sential building block of numerous applications that holds when the communication is (supposedly) secured. rely on a precise notion of time. The deployment of clock arXiv:1811.08569v1 [cs.CR] 21 Nov 2018 synchronization for controlling system clocks of critical appli- A. Contributions cations in telecommunication, industrial automation, financial markets, avionics, or energy distribution has increased the The main contributions of this paper are the following: dependency of critical infrastructures on clocks synchronized • Precision Time Protocol (PTP) traffic detection by with increasingly high precision. Many processes, especially statistical analysis: We present a method for statistical in measurement, control, telecommunications, industrial and traffic analysis of PTP’s 2-step mode that allows to identify financial applications are not only sensitive to errors in the value PTP traffic even if it is encrypted and transmitted together domain but also to errors in the time domain. Examples for strict with other traffic. We show that some statistical properties dependencies on precise time are safety-critical applications (length, timing, and direction) are sufficient to identify in the Smart Grid, which require an accuracy of 1 to 100 µs PTP traffic and the particular PTP message types with very (10 µs in case of current differential line protection with high high probability — even when the traffic is encrypted. fault current sensitivity [1, 2]) or MiFID II in the financial • Selective message delay attacks on encrypted traffic: sector, requiring an accuracy of up to 100 µs [3, 4, 5]. Cellular Using the properties identified in the traffic analysis, we networks also have strong requirements for synchronized clocks design and implement selective message delay attacks on (≤ 1 µs) [6]. Errors in clock synchronization can lead to wrong encrypted traffic. This shows that delay attacks can be timings and may therefore originate faulty sensor reports, conducted on PTP even when it is (supposedly) secured R. ANNESSI, J. FABINI, F.IGLESIAS, AND T. ZSEBY: ENCRYPTION IS FUTILE: DELAY ATTACKS ON HIGH-PRECISION CLOCK SYNCHRONIZATION 2 with state-of-the-art network encryption schemes such as to eliminate software uncertainty. PTP assumes trustworthy IPsec, MACsec, or TLS. and somewhat deterministic networks with low latency that • Countermeasures: We discuss countermeasures against are entirely under control of the operator. It can be run over a traffic analysis (length padding, timing randomization), Local Area Network (LAN) via Ethernet or over a Wide Area selective message delay attacks (strict replay protection), Network (WAN) via UDP. and asymmetric link delay attacks (One-Way Delay New applications that require increasingly precise clock (OWD) limits). synchronization lead to PTP being deployed also in critical • General clock synchronization limitations in adversar- infrastructures and other areas that PTP has not been designed ial settings: We analyze the theoretical foundations that for specifically. Base stations in mobile networks that depend make clock synchronization protocols susceptible to delay on highly accurate time are a prominent example. Originally, attacks and identify the main vulnerability to be the delay manufacturers used GPS PPS to synchronize clocks. Nowadays compensation mechanism, which is necessary to achieve manufacturers also offer PTP as an alternative that is widely high precision. This leads us to asymmetric link delay used. Given the fact that base stations typically use WANs attacks that cannot be prevented by encryption. While to connect to their core network, employing PTP contradicts additional knowledge of the underlying communication the original assumptions of being used within LANs. In this network can bound the maximum impact of delay attacks, way, new attack vectors are created such as the delay attacks we argue that clock synchronization protocols cannot be presented in this paper. More examples include but are not designed in a way that prevents asymmetric link delay limited to areas such as Smart Grids or financial applications. attacks entirely. The resulting bounds, which we found based on our analysis, A. The Two Phases in Clock Synchronization do not satisfy requirements with respect to high-precision Clock synchronization algorithms aim at synchronizing a clock synchronization. Therefore, high precision can only be slave clock to a master clock by exchanging timestamped guaranteed on trusted networks. messages over packet-switched networks. In this paper we assume that the master’s clock is accurate and reliable. Details on how the master implements and accesses such a reliable II. BACKGROUND clock are out of scope of this paper. Network-based clock Each clock has a natural drift caused by the non-ideality of synchronization protocols depend on two distinct phases that physical oscillators such an oscillator’s frequency affected by will be discussed below: (a) clock offset measurement and (b) temperature. The aim of clock synchronization is to keep clocks delay measurement. within acceptable boundaries. Currently, there are two widely a) Clock Offset Measurement Phase: The goal of the used technologies for high-precision clock synchronization: clock offset measurement phase is to calculate the relative (1) the satellite-based Global Positioning System (GPS) for difference between the slave and master clocks. Clock offset Pulses per Second (PPS) synchronization to global Universal can either be measured in a single message (1-step mode) Time Coordinated (UTC), and PTP targeted for network-based supported by both NTP and PTP or in two messages (2-step clock synchronization to a local clock. The main disadvantages mode) supported by PTP. In any case, the master sends a SYNC of GPS PPS are that it is operated by a single entity (the message to the slaves, and the slave records the transmitting US Air Force) and that it
Load more

Recommended publications
  • Introduction to Public Key Cryptography and Clock Arithmetic Lecture Notes for Access 2010, by Erin Chamberlain and Nick Korevaar
    1 Introduction to Public Key Cryptography and Clock Arithmetic Lecture notes for Access 2010, by Erin Chamberlain and Nick Korevaar We’ve discussed Caesar Shifts and other mono-alphabetic substitution ciphers, and we’ve seen how easy it can be to break these ciphers by using frequency analysis. If Mary Queen of Scots had known this, perhaps she would not have been executed. It was a long time from Mary Queen of Scots and substitution ciphers until the end of the 1900’s. Cryptography underwent the evolutionary and revolutionary changes which Si- mon Singh chronicles in The Code Book. If you are so inclined and have appropriate leisure time, you might enjoy reading Chapters 2-5, to learn some of these historical cryptography highlights: People came up with more complicated substitution ciphers, for example the Vigen`ere square. This Great Cipher of France baffled people for quite a while but a de- termined cryptographer Etienne Bazeries had a Eureka moment after three years of work, cracked the code, and possibly found the true identity of the Man in the Iron Mask, one of the great mysteries of the seventeeth century. Edgar Allan Poe and Sir Arthur Conan Doyle even dabbled in cryptanalysis. Secrecy was still a problem though because the key needed to be sent, and with the key anyone could encrypt and decrypt the messages. Frequency analysis was used to break all of these codes. In 1918 Scherbius invented his Enigma machine, but Alan Turing’s machine (the first computer?) helped in figuring out that supposedly unbreakable code, and hastened the end of the second World War.
    [Show full text]
  • Which Time Server Option Is Best for Synchronizing Your Clocks
    WHICH TIME SERVER OPTION IS BEST FOR SYNCHRONIZING YOUR CLOCKS? Any electronic device that automatically displays REGARDING MASTER the current local time – your clocks, phone, tablet, TIME CONTROLLERS computer and even most TVs – has to pull that time from a time server. AND The time server acts as a messenger of sorts; IP NETWORK CLOCKS it reads the time from a reference clock and distributes that information via a computer network (ETHERNET OR WI-FI) to your device when the device requests it. The time server could be a local network time server or an internet time server. SNTP, or Simple Network Time Protocol, is an internet standard protocol that allows a clock or device to contact a server and get the current time. It’s a simplification of the more robustNTP (Network Time Protocol) and is used in most embedded devices and computers. Once the device receives the current Coordinated Universal Time (UTC), the device applies offsets such as time zone or daylight saving time considerations, as well as the time spent on the network retrieving the time, before displaying the accurate local time. January 2018 AMERICAN TIME WHITE PAPER BY: MAX BLOM When it comes to syncing time for your organization’s clocks, you have 3 options: Let’s take a look at how each of these options work, their pros and cons, and our recommendation. Port 123 is reserved specifically for External Server IP Address NTP/SNTP communication 1 The NIST – the U.S. Department of Commerce’s National Institute of Standards and Technology – is the primary source for synchronizing time systems in the U.S.
    [Show full text]
  • Endrun TECHNOLOGIES Præcis Cntp Network Time Server
    Smarter Timing Solutions EndRun TECHNOLOGIES Præcis Cntp Network Time Server User’s Manual Præcis Cntp Network Time Server User’s Manual EndRun Technologies 1360 North Dutton Avenue #200 Santa Rosa, California USA 95401 Phone 707-573-8633 • Fax 707-573-8619 Preface Thank you for purchasing the Præcis Cntp Network Time Server. Our goal in developing this product is to bring precise, Universal Coordinated Time (UTC) into your network quickly, easily and reliably. Your new Præcis Cntp is fabricated using the highest quality materials and manufacturing processes available today, and will give you years of troublefree service. About EndRun Technologies Founded in 1998 and headquartered in Santa Rosa, California, we are the leaders in the exciting new time and frequency distribution technology based on the Code Division Multiple Access (CDMA) mobile telecommunications infrastructure. Our innovative designs and painstaking attention to the details of efficient manufacturability have made us the first to bring this technology to the broad synchronization market at prices small businesses can afford. EndRun Technologies markets this technology in three major product lines: Network Time Sources/Servers – These units are configured for optimum performance in operation with network servers/networks running the Internet protocol known as the Network Time Protocol (NTP). Instrumentation Time and Frequency References – These products provide UTC traceable time and frequency signals for use in precision test and measurement instrumentation. OEM Time and Frequency Engines – These products provide the core time and frequency capabilities to our customers who require lower cost and tighter integration with their own products. About this manual This manual will guide you through simple installation and set up procedures.
    [Show full text]
  • The Mathemathics of Secrets.Pdf
    THE MATHEMATICS OF SECRETS THE MATHEMATICS OF SECRETS CRYPTOGRAPHY FROM CAESAR CIPHERS TO DIGITAL ENCRYPTION JOSHUA HOLDEN PRINCETON UNIVERSITY PRESS PRINCETON AND OXFORD Copyright c 2017 by Princeton University Press Published by Princeton University Press, 41 William Street, Princeton, New Jersey 08540 In the United Kingdom: Princeton University Press, 6 Oxford Street, Woodstock, Oxfordshire OX20 1TR press.princeton.edu Jacket image courtesy of Shutterstock; design by Lorraine Betz Doneker All Rights Reserved Library of Congress Cataloging-in-Publication Data Names: Holden, Joshua, 1970– author. Title: The mathematics of secrets : cryptography from Caesar ciphers to digital encryption / Joshua Holden. Description: Princeton : Princeton University Press, [2017] | Includes bibliographical references and index. Identifiers: LCCN 2016014840 | ISBN 9780691141756 (hardcover : alk. paper) Subjects: LCSH: Cryptography—Mathematics. | Ciphers. | Computer security. Classification: LCC Z103 .H664 2017 | DDC 005.8/2—dc23 LC record available at https://lccn.loc.gov/2016014840 British Library Cataloging-in-Publication Data is available This book has been composed in Linux Libertine Printed on acid-free paper. ∞ Printed in the United States of America 13579108642 To Lana and Richard for their love and support CONTENTS Preface xi Acknowledgments xiii Introduction to Ciphers and Substitution 1 1.1 Alice and Bob and Carl and Julius: Terminology and Caesar Cipher 1 1.2 The Key to the Matter: Generalizing the Caesar Cipher 4 1.3 Multiplicative Ciphers 6
    [Show full text]
  • NBAR2 Standard Protocol Pack 1.0
    NBAR2 Standard Protocol Pack 1.0 Americas Headquarters Cisco Systems, Inc. 170 West Tasman Drive San Jose, CA 95134-1706 USA http://www.cisco.com Tel: 408 526-4000 800 553-NETS (6387) Fax: 408 527-0883 © 2013 Cisco Systems, Inc. All rights reserved. CONTENTS CHAPTER 1 Release Notes for NBAR2 Standard Protocol Pack 1.0 1 CHAPTER 2 BGP 3 BITTORRENT 6 CITRIX 7 DHCP 8 DIRECTCONNECT 9 DNS 10 EDONKEY 11 EGP 12 EIGRP 13 EXCHANGE 14 FASTTRACK 15 FINGER 16 FTP 17 GNUTELLA 18 GOPHER 19 GRE 20 H323 21 HTTP 22 ICMP 23 IMAP 24 IPINIP 25 IPV6-ICMP 26 IRC 27 KAZAA2 28 KERBEROS 29 L2TP 30 NBAR2 Standard Protocol Pack 1.0 iii Contents LDAP 31 MGCP 32 NETBIOS 33 NETSHOW 34 NFS 35 NNTP 36 NOTES 37 NTP 38 OSPF 39 POP3 40 PPTP 41 PRINTER 42 RIP 43 RTCP 44 RTP 45 RTSP 46 SAP 47 SECURE-FTP 48 SECURE-HTTP 49 SECURE-IMAP 50 SECURE-IRC 51 SECURE-LDAP 52 SECURE-NNTP 53 SECURE-POP3 54 SECURE-TELNET 55 SIP 56 SKINNY 57 SKYPE 58 SMTP 59 SNMP 60 SOCKS 61 SQLNET 62 SQLSERVER 63 SSH 64 STREAMWORK 65 NBAR2 Standard Protocol Pack 1.0 iv Contents SUNRPC 66 SYSLOG 67 TELNET 68 TFTP 69 VDOLIVE 70 WINMX 71 NBAR2 Standard Protocol Pack 1.0 v Contents NBAR2 Standard Protocol Pack 1.0 vi CHAPTER 1 Release Notes for NBAR2 Standard Protocol Pack 1.0 NBAR2 Standard Protocol Pack Overview The Network Based Application Recognition (NBAR2) Standard Protocol Pack 1.0 is provided as the base protocol pack with an unlicensed Cisco image on a device.
    [Show full text]
  • The Enigma History and Mathematics
    The Enigma History and Mathematics by Stephanie Faint A thesis presented to the University of Waterloo in fulfilment of the thesis requirement for the degree of Master of Mathematics m Pure Mathematics Waterloo, Ontario, Canada, 1999 @Stephanie Faint 1999 I hereby declare that I am the sole author of this thesis. I authorize the University of Waterloo to lend this thesis to other institutions or individuals for the purpose of scholarly research. I further authorize the University of Waterloo to reproduce this thesis by pho­ tocopying or by other means, in total or in part, at the request of other institutions or individuals for the purpose of scholarly research. 11 The University of Waterloo requires the signatures of all persons using or pho­ tocopying this thesis. Please sign below, and give address and date. ill Abstract In this thesis we look at 'the solution to the German code machine, the Enigma machine. This solution was originally found by Polish cryptologists. We look at the solution from a historical perspective, but most importantly, from a mathematical point of view. Although there are no complete records of the Polish solution, we try to reconstruct what was done, sometimes filling in blanks, and sometimes finding a more mathematical way than was originally found. We also look at whether the solution would have been possible without the help of information obtained from a German spy. IV Acknowledgements I would like to thank all of the people who helped me write this thesis, and who encouraged me to keep going with it. In particular, I would like to thank my friends and fellow grad students for their support, especially Nico Spronk and Philippe Larocque for their help with latex.
    [Show full text]
  • IBM Z Server Time Protocol Guide
    Front cover Draft Document for Review August 3, 2020 1:37 pm SG24-8480-00 IBM Z Server Time Protocol Guide Octavian Lascu Franco Pinto Gatto Gobehi Hans-Peter Eckam Jeremy Koch Martin Söllig Sebastian Zimmermann Steve Guendert Redbooks Draft Document for Review August 3, 2020 7:26 pm 8480edno.fm IBM Redbooks IBM Z Server Time Protocol Guide August 2020 SG24-8480-00 8480edno.fm Draft Document for Review August 3, 2020 7:26 pm Note: Before using this information and the product it supports, read the information in “Notices” on page vii. First Edition (August 2020) This edition applies to IBM Server Time Protocol for IBM Z and covers IBM z15, IBM z14, and IBM z13 server generations. This document was created or updated on August 3, 2020. © Copyright International Business Machines Corporation 2020. All rights reserved. Note to U.S. Government Users Restricted Rights -- Use, duplication or disclosure restricted by GSA ADP Schedule Contract with IBM Corp. Draft Document for Review August 3, 2020 8:32 pm 8480TOC.fm Contents Notices . vii Trademarks . viii Preface . ix Authors. ix Comments welcome. .x Stay connected to IBM Redbooks . xi Chapter 1. Introduction to Server Time Protocol . 1 1.1 Introduction to time synchronization . 2 1.1.1 Insertion of leap seconds . 2 1.1.2 Time-of-Day (TOD) Clock . 3 1.1.3 Industry requirements . 4 1.1.4 Time synchronization in a Parallel Sysplex. 6 1.2 Overview of Server Time Protocol (STP) . 7 1.3 STP concepts and terminology . 9 1.3.1 STP facility . 9 1.3.2 TOD clock synchronization .
    [Show full text]
  • Ipv6-Security Monitoring
    Security Monitoring ITU/APNIC/MICT IPv6 Security Workshop 23rd – 27th May 2016 Bangkok Last updated 22 July 2014 1 Managing and Monitoring IPv6 Networks p SNMP Monitoring p IPv6-Capable SNMP Management Tools p NetFlow Analysis p Syslog p Keeping accurate time p Intrusion Detection p Managing the Security Configuration 2 Using SNMP for Managing IPv6 Networks 3 What is SNMP? p SNMP – Simple Network Management Protocol p Industry standard, hundreds of tools exist to exploit it p Present on any decent network equipment p Query/response based: GET / SET p Monitoring generally uses GET p Object Identifiers (OIDs) p Keys to identify each piece of data p Concept of MIB (Management Information Base) p Defines a collection of OIDs What is SNMP? p Typical queries n Bytes In/Out on an interface, errors n CPU load n Uptime n Temperature or other vendor specific OIDs p For hosts (servers or workstations) n Disk space n Installed software n Running processes n ... p Windows and UNIX have SNMP agents What is SNMP? p UDP protocol, port 161 p Different versions n v1 (1988) – RFC1155, RFC1156, RFC1157 p Original specification n v2 – RFC1901 ... RFC1908 + RFC2578 p Extends v1, new data types, better retrieval methods (GETBULK) p Used is version v2c (simple security model) n v3 – RFC3411 ... RFC3418 (w/security) p Typically we use SNMPv2 (v2c) SNMP roles p Terminology: n Manager (the monitoring station) n Agent (running on the equipment/server) How does it work? p Basic commands n GET (manager → agent) p Query for a value n GET-NEXT (manager → agent) p Get next value (e.g.
    [Show full text]
  • Emerging Solutions in Time Synchronization Security
    Emerging Solutions in Time Synchronization Security Karen O’Donoghue, [email protected] IEEE/NIST Challenges in the Smart Grid Workshop, 7 September 2014 www.internetsociety.org Agenda • Why Security Now? • Requirements • What currently exists? • IEEE 1588 • IETF NTP NTS • Next steps and parting thoughts… IEEE/NIST Time Challenges in Smart Grid Workshop – 26 Oct 2016 Why Security Now? • Increasing interconnection and decentralization • Increasing evidence of the impact of inadequate security • Interdependency between security and time • Legal and Compliance requirements 3 IEEE/NIST Time Challenges in Smart Grid Workshop – 26 Oct 2016 Requirements for Time Synchronization Security § RFC 7384: Security Requirements of Time Protocols in Packet Switched Networks, Oct 2014 – Threat model § Internal versus external attacker § Man-in-the-middle versus injection § Threats § Requirements analysis § IEEE 1588 requirements analysis – https://ieee-sa.centraldesktop.com/1588/file/27229936/ – (contact me for access to this document if necessary) 4 IEEE/NIST Time Challenges in Smart Grid Workshop – 26 Oct 2016 RFC 7384: Threats • Manipulation of time synchronization packets, • Masquerading as a legitimate participant in the time synchronization protocol, • Replay of legitimate packets, • Tricking nodes into believing time from the wrong master, • Intercepting and removing valid synchronization packets, • Delaying legitimate time synchronization packets on the network, • Denial of service attacks on the network at layer 2 and layer 3, • Denial of service by overloading the cryptographic processing components, • Denial of service by overloading the time synchronization protocol, • Corruption of the time source used by the grand master, • Protocol design and implementation vulnerabilities, and • Using the time synchronization protocol for broader network surveillance and fingerprinting types of activities.
    [Show full text]
  • Towards Low Energy Stream Ciphers
    IACR Transactions on Symmetric Cryptology ISSN 2519-173X, Vol. 2018, No. 2, pp. 1–19. DOI:10.13154/tosc.v2018.i2.1-19 Towards Low Energy Stream Ciphers Subhadeep Banik1, Vasily Mikhalev2, Frederik Armknecht2, Takanori Isobe3, Willi Meier4, Andrey Bogdanov5, Yuhei Watanabe6 and Francesco Regazzoni7 1 Security and Cryptography Laboratory (LASEC), École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland [email protected] 2 University of Mannheim, Mannheim, Germany {mikhalev,armknecht}@uni-mannheim.de 3 University of Hyogo, Hyogo, Japan [email protected] 4 University of Applied Sciences and Arts Northwestern Switzerland (FHNW), Windisch, Switzerland [email protected] 5 Department of Applied Mathematics and Computer Science (DTU Compute), Technical University of Denmark, Kongens Lyngby, Denmark [email protected] 6 National Institute of Advanced Industrial Science and Technology, Osaka, Japan [email protected] 7 Università della Svizzera italiana (USI), Lugano, Switzerland [email protected] Abstract. Energy optimization is an important design aspect of lightweight cryptog- raphy. Since low energy ciphers drain less battery, they are invaluable components of devices that operate on a tight energy budget such as handheld devices or RFID tags. At Asiacrypt 2015, Banik et al. presented the block cipher family Midori which was designed to optimize the energy consumed per encryption and which reduces the energy consumption by more than 30% compared to previous block ciphers. However, if one has to encrypt/decrypt longer streams of data, i.e. for bulk data encryption/decryption, it is expected that a stream cipher should perform even better than block ciphers in terms of energy required to encrypt.
    [Show full text]
  • Design of an Efficient Architecture for Advanced Encryption Standard Algorithm Using Systolic Structures
    International Conference of High Performance Computing (HiPC 2005) Design of an Efficient Architecture for Advanced Encryption Standard Algorithm Using Systolic Structures 1Suresh Sharma, 2T S B Sudarshan 1Student, Computer Science & Engineering, IIT, Khragpur 2 Assistant Professor, Computer Science & Information Systems, BITS, Pilani. fashion and communication with the memory or Abstract: external devices occurs only through the boundary This Paper presents a systolic architecture for cells. Advanced Encryption standard (AES). Use of systolic The architecture uses similarities of encryption and architecture has improved the hardware complexity decryption to provide a high level of performance and the rate of encryption/decryption. Similarities of while keeping the chip size small. The architecture encryption and decryption are used to provide a high is highly regular and scalable. The key size can performance using an efficient architecture. The easily be changed from 128 to 192 or 256 bits by efficiency of the design is quite high due to use of making very few changes in the design. short and balanced combinational paths in the design. The paper is organized as follows. Section 2 gives a The encryption or decryption rate is 3.2-Bits per brief overview of the AES algorithm. In section 3, a clock-cycle and due to the use of pipelined systolic summary of available AES architecture is given and architecture and balanced combinational paths the proposed AES hardware architecture is maximum clock frequency for the design is quite described. The performance of the architecture is high. compared with other implementations in section 4. Concluding remarks are given in section 5. Index terms:- Advanced Encryption standard (AES), Systolic Architecture, processing elements, 2.
    [Show full text]
  • Cumulative Message Authentication Codes for Resource
    1 Cumulative Message Authentication Codes for Resource-Constrained IoT Networks He Li, Vireshwar Kumar, Member, IEEE, Jung-Min (Jerry) Park, Fellow, IEEE, and Yaling Yang, Member, IEEE Abstract—In resource-constrained IoT networks, the use of problems: the computational burden on the devices for gen- conventional message authentication codes (MACs) to provide erating/verifying the MAC, and the additional communication message authentication and integrity is not possible due to the overhead incurred due to the inclusion of the MAC in each large size of the MAC output. A straightforward yet naive solution to this problem is to employ a truncated MAC which message frame/packet. The first problem can be addressed by undesirably sacrifices cryptographic strength in exchange for using dedicated hardware and cryptographic accelerators [11], reduced communication overhead. In this paper, we address this [31]. However, the second problem is not as easy to address. problem by proposing a novel approach for message authentica- tion called Cumulative Message Authentication Code (CuMAC), Problem. The cryptographic strength of a MAC depends which consists of two distinctive procedures: aggregation and on the cryptographic strength of the underlying cryptographic accumulation. In aggregation, a sender generates compact au- primitive (e.g. a hash or block cipher), the size and quality of thentication tags from segments of multiple MACs by using a systematic encoding procedure. In accumulation, a receiver the key, and the size of the MAC output. Hence, a conventional accumulates the cryptographic strength of the underlying MAC MAC scheme typically employs at least a few hundred bits by collecting and verifying the authentication tags.
    [Show full text]