IACR News
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27 February 2018
Bertram Poettering
ePrint ReportElizabeth A. Quaglia, Ben Smyth
ePrint ReportJeremiah Blocki, Ling Ren, Samson Zhou
ePrint ReportOur contributions are as follows: First, we provide the first reduction proving that, in the parallel random oracle model, the bandwidth hardness of a Data-Independent Memory Hard Function (iMHF) is described by the red-blue pebbling cost of the directed acyclic graph (DAG) associated with that iMHF. Second, we show that the goals of designing an MHF with high CMC/bandwidth hardness are well aligned. In particular, we prove that any function with high CMC also has relatively high bandwidth costs. This result leads to the first unconditional lower bound on the bandwidth cost of scrypt. Third, we analyze the bandwidth hardness of several prominent iMHF candidates such as Argon2i (Biryukov et. al., 2015), winner of the password hashing competition, aATSample and DRSample (Alwen et. al., CCS 2017) --- the first practical iMHF with asymptotically optimal CMC. More specifically, we show that Argon2i is maximally bandwidth hard as long as the cache-size $m$ is at most $m \in O(n^{2/3-\epsilon})$ where $n$ is the total number of data-labels produced during computation. We also show that aATSample and DRSample are maximally bandwidth hard as long as the cache-size is $m \in O(n^{1-\epsilon})$. Finally, we show that the problem of finding a red-blue pebbling with minimum bandwidth cost is NP-hard.
Shruti Tople, Yaoqi Jia, Prateek Saxena
ePrint ReportIn this work, we present PRO-ORAM --- an ORAM construction that achieves constant latencies per access in a large class of applications. PRO-ORAM theoretically and empirically guarantees this for read-only data access patterns, wherein data is written once followed by read requests. It makes hiding data access pattern practical for read-only workloads, incurring sub-second computational latencies per access for data blocks of 256 KB, over large (gigabyte-sized) datasets.PRO-ORAM supports throughputs of tens to hundreds of MBps for fetching blocks, which exceeds network bandwidth available to average users today. Our experiments suggest that dominant factor in latency offered by PRO-ORAM is the inherent network throughput of transferring final blocks, rather than the computational latencies of the protocol. At its heart, PRO-ORAM utilizes key observations enabling an aggressively parallelized algorithm of an ORAM construction and a permutation operation, as well as the use of trusted computing technique (SGX) that not only provides safety but also offers the advantage of lowering communication costs.
26 February 2018
Jakub Breier, Dirmanto Jap, Xiaolu Hou, Shivam Bhasin
ePrint ReportIn this work, we show how bit permutations introduce a side-channel vulnerability that can be exploited to extract the secret key from the cipher. Such vulnerabilities are specific to bit permutations and do not occur in other state-wise diffusion alternatives. We propose Side-Channel Assisted Differential-Plaintext Attack (SCADPA) which targets this vulnerability in bit permutation operation. SCADPA is experimentally demonstrated on PRESENT-80 on an 8-bit microcontroller, with the best case key recovery in 17 encryptions. The attack is then extended to latest bit-permutation based cipher GIFT, allowing full key recovery in 36 encryptions. We also propose and experimentally verify an automatic threshold method which can be easily applied to SCADPA, allowing automation of the attack. Moreover, SCADPA on bit permutations has other applications. Application for reverse engineering secret sboxes in PRESENT-like proprietary ciphers is shown. We also highlight a special case, where fixing one vulnerability opens another one. This is shown by applying SCADPA on some assembly level fault attack countermeasures, rendering it less secure than unprotected implementations. Lastly, we also provide several different attack scenarios, such as targeting different encryption modes.
Jakub Breier, Xiaolu Hou, Yang Liu
ePrint ReportIn this paper we propose an evaluation framework that can be used for analyzing the effectivity of software encoding countermeasures against fault attacks. We first formalize the encoding schemes in software, helping us to define what properties are required when designing a fault protection. These findings show that using anticodes in such countermeasure can increase its detection capabilities. We provide a way to generate a code according to user criteria and also a method to evaluate the level of protection of assembly implementations using encoding schemes. This evaluation is based on static code analysis and provides a practical information on how good will the protection be on a real device. Finally, we verify our findings by implementing a block cipher PRESENT, protected by encoding scheme based on anticodes, and provide a detailed evaluation of such implementation.
Mihir Bellare, Wei Dai
ePrint ReportS. Dov Gordon, Samuel Ranellucci, Xiao Wang
ePrint ReportPanagiotis Grontas, Aris Pagourtzis, Alexandros Zacharakis, Bingsheng Zhang
ePrint ReportAhmad Khoureich Ka
ePrint ReportCommitting to Quantum Resistance: A Slow Defence for Bitcoin against a Fast Quantum Computing Attack
I. Stewart, D. Ilie, A. Zamyatin, S. Werner, M.F. Torshizi, W.J. Knottenbelt
ePrint ReportThibaut Horel, Sunoo Park, Silas Richelson, Vinod Vaikuntanathan
ePrint ReportWe show that even in the pessimistic scenario described, citizens can communicate securely and undetectably. In our terminology, this translates to a positive statement: all semantically secure encryption schemes support subliminal communication. Informally, this means that there is a two-party protocol between Alice and Bob where the parties exchange ciphertexts of what appears to be a normal conversation even to someone who knows the secret keys and thus can read the corresponding plaintexts. And yet, at the end of the protocol, Alice will have transmitted her secret message to Bob. Our security definition requires that the adversary not be able to tell whether Alice and Bob are just having a normal conversation using the mandated encryption scheme, or they are using the mandated encryption scheme for subliminal communication.
Our topics may be thought to fall broadly within the realm of steganography: the science of hiding secret communication within innocent-looking messages, or cover objects. However, we deal with the non-standard setting of an adversarially chosen distribution of cover objects (i.e., a stronger-than-usual adversary), and we take advantage of the fact that our cover objects are ciphertexts of a semantically secure encryption scheme to bypass impossibility results which we show for broader classes of steganographic schemes. We give several constructions of subliminal communication schemes under the assumption that key exchange protocols with pseudorandom messages exist (such as Diffie-Hellman, which in fact has truly random messages). Each construction leverages the assumed semantic security of the adversarially chosen encryption scheme, in order to achieve subliminal communication.
Prasanna Ravi, Shivam Bhasin, Anupam Chattopadhyay
ePrint ReportAllison Bishop, Lucas Kowalczyk, Tal Malkin, Valerio Pastro, Mariana Raykova, Kevin Shi
ePrint ReportGuilin, China, 8 August - 9 August 2018
Event CalendarSubmission deadline: 20 April 2018
Notification: 10 June 2018
25 February 2018
Research Fellow, NZ Institute for Security and Crime Science & Cyber Security Researchers of Waikato
University of Waikato
Job PostingWe are seeking to appoint a full time fixed term Research Fellow to contribute to our research objectives associated with cybercrime, computer security and cloud computing. This position has responsibilities to achieve research objectives associated with the STRATUS industry partners.
A PhD in cyber security, cybercrime, computer science or a related field is essential as is having demonstrated research ability in cyber security and cybercrime. A requirement of this position is the ability to commercialise research prototypes into products/services and the demonstrated ability to publish in high quality academic journals, work collaboratively with others and undertake some teaching if required. Preference will be given to candidates who have work experience with cybercrime, security, intelligence, or law enforcement agencies including work experience in the cybercrime, security digital forensics, machine learning, applied cryptography, etc. Salary will be in the range of NZ$74,034 to NZ$89,163 per year, depending on qualifications, skills and experience.
Enquiries of an academic nature should be sent to Assoc. Prof. Ryan Ko – Director, NZ Institute for Security and Crime Science, ryan.ko (at) waikato.ac.nz
Fixed-term until October 2020. Closing date: 16 March 2018 (NZ time) Vacancy number: 380090
Closing date for applications: 16 March 2018
Contact: Ryan Ko (ryan.ko AT waikato.ac.nz)
More information: http://www.jobs.waikato.ac.nz
University of Waikato
Job PostingCyber security represents a large growth industry, which both tertiary and private sector organisations are collaborating on. The University of Waikato and NZ’s leading cyber security consultancy firm Aura information security are jointly seeking applicants for an exciting new position within the computer science faculty based in Hamilton. The Aura professor of cyber security will be expected to contribute to both the research and teaching programmes of the University, and in the research and consulting programme of Aura Information Security. The focus of the research programme for the University and Aura is in penetration testing, but expertise in other areas of cyber security (e.g. artificial intelligence and machine learning for cyber security, post-quantum cryptography, applied cryptography, cryptanalysis, etc) will also be helpful. This position will suit an ambitious academic with an outstanding teaching and research record and a strong interest in engagement with the cyber security industry, as well as research and development leaders in the cyber security industry who wishes to operate in an academic environment. Salary is negotiable.
Applications close 23 March 2018.
Closing date for applications: 23 March 2018
Contact: Ryan Ko (ryan.ko (at) waikato.ac.nz)
More information: https://www.waikato.ac.nz/vacancies/current-vacancies
Duality Technologies, Newark NJ, USA
Job PostingDuality Technologies is hiring a cryptographic engineer who has interest in developing and applying encrypted computing technologies. Implementation or prototyping experience is a plus, but not critical. The ideal candidate is a team player who is looking to grow with the company.
We are interested in candidates who have had exposure to a mixture of homomorphic encryption, secure multi-party computation, set intersection, functional encryption, cryptographic obfuscation and related techniques, but we don’t expect a successful candidate to have expertise in all of these areas.
We are interested in candidates at all levels from a fresh PhD graduate to experienced researchers / scientists / engineers. The candidate is expected to work some of the time from our office in Newark NJ. Occasional travel to other offices in Cambridge MA or Tel Aviv Israel is expected.
Requirements:
• A PhD in Computer Science, Computer Engineering, Applied Mathematics or a related field.
• Experience with modern encrypted computing technologies.
• An ability and willingness to work on a team.
Desired Skills:
• Experience with homomorphic encryption, lattice cryptography, secure multiparty computation or other encrypted computing technologies
• Experience implementing lattice cryptography in software or hardware
• Familiarity with C/C++, Java, Python
• Able to work in a dynamic, fast-paced environment
Closing date for applications: 31 December 2019
Contact: Kurt Rohloff, PhD.
CTO, Duality Technologies
krohloff (at) duality.cloud
More information: https://www.duality.cloud
University of Salerno, ITALY
Job PostingCandidates are expected to have a strong publication record (e.g., IACR conferences, CCS, IEEE S&P,....). The positions will be available soon.
Closing date for applications: 31 May 2018
Contact: Ivan Visconti, ivan.visconti (at) gmail.com
More information: https://sites.google.com/site/ivanvisconti/post-doc
23 February 2018
University of Bristol, United Kingdom
Job PostingThis advert is for:
S4 Compiler and Language based Leakage Mitigation: the aim of the studentship is to explore techniques by which programs written in standard C, or Assembly, can be augmented to include information about leakage sensitive variables with the aim of feeding this information down into the various compilation steps such that tools can insert mitigation strategies with minimal user interaction. The ideal candidate will have a strong background (or at least interest) in computer science (in particular languages and compilers), and some familiarity with side channel attacks.
Supervisor: Elisabeth Oswald
The studentship S4 supports EU/UK nationals with a tax-free stipend of around 22k GBP. The latest starting date for students is September 30th 2018.
You may apply for one, some, or all advertised studentships simultaneously (please explain your choice in your application). Your application needs to be filed via: http://www.bristol.ac.uk/study/postgraduate/apply/.
This advert has a nominal end date of 1.5.2018, but we will make appointments as soon as we have identified candidates with the right background.
Closing date for applications: 1 May 2018
Contact: Prof. Elisabeth Oswald, Elisabeth.Oswald (at) bristol.ac.uk