Monash Cybersecurity Reading Group
Welcome to the Monash Cybersecurity Reading Group (MCSRG) web page. We are a research group of
academics and students, based at the Faculty of Information Technology, Monash University.
We share a common interest in all aspects of cyber security and meet to read and discuss recent papers on topics of interest to the group.
More information on the group's activities is available below. Group meetings times and discussion topics are advertised below. Meetings are held at Room G12A, 14 Rainforest Walk, Clayton Campus, Monash University,
unless otherwise advised.
Visitors are welcome. For more information, please contact Ron Steinfeld (firstname.lastname@example.org).
- January 2017: This year, we will have regular bi-weekly reading group seminars.
Usually, each seminar will be presented by a different Monash `Regular Presenting Group Member' (those members are listed below), going by alphabetic order of first name (except for the first seminar, which will be given by Ron S.).
Details of upcoming seminars will be posted about a week before each seminar on this website.
Regular Presenting Group Members (in alphabetic order of first name):
- Friday, 28 July 2017, 2pm-3pm, Room G12A, 14 Rainforest Walk, Clayton Campus.
Presenter: Yevhen Zolotavkin (Monash U.)
Talk Title: Incentive compatibility of pay per last N shares in Bitcoin mining pools
Abstract: Pay per last N shares (PPLNS) is a popular pool mining reward mechanism on a number of cryptocurrencies,
including Bitcoin. In PPLSN pools, miners may stand to benefit by delaying reports of found shares. This attack may entail
unfair or inefficient outcomes. We propose a simple but general game theoretical model of delays in PPLNS. We derive conditions
for incentive compatible rewards, showing that the power of the most powerful miner determines whether incentives are compatible
or not. An efficient algorithm to find Nash equilibria is put forward, and used to show how fairness and efficiency deteriorate
with inside-pool inequality. In pools where all players have comparable computational power incentives to deviate from protocol
are minor, but gains may be considerable in pools where miner's resources are unequal. We explore how our findings can be
applied to ameliorate delay attacks by fitting real-world parameters to our model.
- Friday, 30 June 2017, 2pm-3pm, Room G12A, 14 Rainforest Walk, Clayton Campus.
Presenter: Trung Dinh (Monash U.)
Talk Title: Practical Packing Method in Somewhat Homomorphic Encryption
Abstract: This reading group seminar will present the following paper:
The paper abstract follows:
Yasuda M., Shimoyama T., Kogure J., Yokoyama K., Koshiba T. (2014) Practical Packing Method in Somewhat Homomorphic Encryption. In: Garcia-Alfaro J., Lioudakis G., Cuppens-Boulahia N., Foley S., Fitzgerald W. (eds) Data Privacy Management and Autonomous Spontaneous Security. Lecture Notes in Computer Science, vol 8247. Springer, Berlin, Heidelberg.
Somewhat homomorphic encryption is public key encryp-
tion supporting a limited number of both additions and multiplications
on encrypted data, which is useful for performing fundamental compu-
tations with protecting the data confidentiality. In this paper, we focus
on the scheme proposed by Lauter, Naehrig and Vaikuntanathan (ACM
CCSW 2011), and present two types of packed ciphertexts based on their
packing technique. Combinations of two types of our packing method give
practical size and performance for wider computations such as statistical
analysis and distances. To demonstrate its efficiency, we implemented the
scheme with our packing method for secure Hamming distance, which is
often used in privacy-preserving biometrics. For secure Hamming dis-
tance between two binary vectors of 2048-bit, it takes 5.31ms on an Intel Xeon X3480 at 3.07GHz. This gives
the best performance in the state-of-the-art work using homomorphic
- Friday, 16 June 2017, 2pm-3pm, Room G12A, 14 Rainforest Walk, Clayton Campus.
Presenter: Shangqi Lai (Monash U.)
Talk Title: Introduction to the Spark distributed computing framework
Abstract: This seminar will review Spark, a recent distributed computing framework based upon Hadoop. It enables high
performance computation on RAM. The talk aims to provide a basic picture of this system.
- Friday, 2 June 2017, 2pm-4pm, Room G12A, 14 Rainforest Walk, Clayton Campus.
We will have two presentations at this meeting as follows.
Presenter 1: Cong Zuo (Monash U.)
Talk 1 Title: Dynamic Searchable Symmetric Encryption
Abstract 1: A Searchable Symmetric Encryption (SSE) scheme allows a server to search a user’s data without having to decrypt the data. This provides the user with a high degree
of privacy and is particularly useful when data is stored on Cloud. Numerous SSE schemes have already been proposed and while most have excellent security properties, few meet the dynamic update of the encrypted data. Unfortunately, these efficient, dynamic searchable encryption
schemes suffer from various drawbacks. In this presentation, we would mainly introduce the Cash et al.'s dynamic searchable encryption scheme which has been published in NDSS14.
Short biography (presenter 1): Cong Zuo received his bachelor degree from the School of Computer Engineering
at Nanjing Institute of Technology, and his master degree from the School of Computer Science and Information
Engineering at Zhejiang Gongshang University, China. He is currently a PhD Student at Monash University under
the supervision of Dr Joseph K. Liu. His main research interest is the applied cryptography.
Presenter 2: Lei Xu (Nanjing University of Science & Technology, China)
Talk 2 Title: Dynamic Searchable Symmetric Encryption with Physical Deletion and Small Leakage
Abstract 2: Dynamic Searchable Symmetric Encryption (DSSE) allows a client not only to search over ciphertexts
as the traditional searchable symmetric encryption does, but also to update these ciphertexts according to requirements,
e.g., adding or deleting some ciphertexts. It has been recognized as a fundamental and promising method to build secure
cloud storage. This paper mainly proposes a new DSSE scheme to overcome the drawbacks of previous schemes in the
state-of-art. The biggest challenge is to realize the physical deletion of ciphertexts with small leakage.
It employ both logical and physical deletions, and run physical deletion in due course to avoid extra information
leakage. Their instantiation achieves noticeable improvements throughout all following aspects: search performance,
storage cost, functionality, and information leakage when operating its functions. It also demonstrate its provable
security under adaptive attacks and practical performance according to experimental results.
(paper to appear at ACISP 2017).
Short biography (presenter 2): Lei Xu is a joint training Ph.D. student at Nanjing University of Science & Technology.
He is currently visiting the Faculty of Information Technology, Monash University. His main research interests focus
on public key cryptography and information security, especially searchable encryption mechanism and identity-based
encryption system. And his future work will be engaged to study how to use better algebra tools to construct secure
and efficient dynamic symmetric searchable encryption schemes.
- Friday, 28 April 2017, 11am-1pm, Room G12A, 14 Rainforest Walk, Clayton Campus.
Presenter: Shabnam Kasra (Monash U.)
Talk Title: Multi-user Cloud-based Secure Keyword Search
Abstract: At this seminar, I will discuss our recent paper on a multi-user Symmetric Searchable Encryption (SSE)
scheme. Our multi-user scheme is an extension of the single-user Oblivious Cross Tags (OXT) protocol in the following paper:
In our multi-user scheme, multiple clients can search the encrypted data on the database without needing to contact
data owner for online assistance. More precisely, a user can perform a search query by interacting with the server
and any t-1 ‘helping’ users (for a threshold parameter t).
- D. Cash, S. Jarecki, C. S. Jutla, H. Krawczyk, M. Rosu, and M. Steiner. Highly scalable searchable symmetric encryption with support
for boolean queries. In CRYPTO 2013. Available here.
- Friday, 7 April 2017, 2pm-4pm, Room G12A, 14 Rainforest Walk, Clayton Campus.
Presenter: Muhammed Esgin (Monash U.)
Talk Title: Multi-Key Fully Homomorphic Encryption based on Learning With Errors Problem
Abstract: The traditional Fully Homomorphic Encryption (FHE) schemes, which enables one to do arbitrary
computations over encrypted data without having any knowledge about the secret key, only allow ciphertexts to
be encrypted under the same key. Thus, when considering a Multi-Party Computation (MPC) scenario where the
function to be computed is decided after the data is encrypted and the data owners outsource the computation
to a third party (say, the cloud) so that they can go offline when the actual computation takes place, it is
quite useful to have an FHE scheme (or more precisely, a Multi-Key FHE scheme) which allows to do computations
over data encrypted under different keys. In this talk, we will look at a Multi-Key Fully Homomorphic Encryption
(MK-FHE) scheme proposed by Pratyay Mukherjee and Daniel Wichs at EUROCRYPT 2016. The scheme is based on the
so-called GSW FHE scheme and Learning With Errors (LWE) problem.
The talk is based on the following paper (Our focus is on Section 5 of the paper and the sections before that for preliminaries):
- Pratyay Mukherjee and Daniel Wichs. "Two Round Multiparty Computation via Multi-Key FHE", In Proceedings of EUROCRYPT 2016. Available here.
- Friday, 24 March 2017, 2pm-4pm, Room G12A, 14 Rainforest Walk, Clayton Campus.
Presenter: Joseph Liu (Monash U.)
Talk Title: (Linkable) Ring Signature and its Applications (Related to Blockchain)
Abstract: Ring signature is a kind of anonymous signature.
Verifier only knows that the signer is a user within a group, yet does not know the identity of this signer.
In this talk, I will cover the basics of ring signature and linkable ring signature, including the concept,
applications, technical constructions and variants. I will further relate linkable ring signature to
Monero, the current third largest blockchain-based cryptocurrency in the world, which is considered to be the
most commercial deployment of linkable ring signature nowadays.
- Friday, 10 March 2017, 2pm-4pm, Room G12A, 14 Rainforest Walk, Clayton Campus.
Presenter: Bin Yu (Monash U.)
Talk Title: Enigma: A blockchain based decentralized computation platform
Abstract: We will discuss how the Blockchain technology is applied to build an
autonomous decentralized multiparty-computation platform which is free of a trusted third party and is publicly verifiable.
- Peters, G. W., & Panayi, E. (2016). `Understanding Modern Banking Ledgers through Blockchain Technologies: Future of
Transaction Processing and Smart Contracts on the Internet of Money.' In `Banking Beyond Banks and Money', Springer International
Publishing, pp. 239-278. Available here.
- The Enigma website is here.
- The Enigma paper is available here.
- Tuesday, 21 February 2017, 11:00am-12:00pm, Room 115, 25 Exhibition Walk, Clayton Campus.
Presenter: Huaxiong Wang (Nanyang Technological University, Singapore)
Talk Title: On Efficient Communication of Secret Reconstruction in Secret Sharing Schemes
Abstract: A secret sharing scheme typically requires secure communications in each of two distribution phases: (1)
a dealer distributes shares to participants (share distribution phase); and later (2) the participants in some authorised subset
send their share information to a combiner (secret reconstruction phase). While problems on storage required for participants,
for example, the size of shares, have been well studied, problems regarding the communication complexity of the two distribution
phases seem to have been mostly neglected in the literature. In this talk, we deal with several communication related problems
in the secret reconstruction phase, and show that there is a tradeoff between the communication costs and the number of participants
involved in the secret reconstruction. We also give an overview on some recent development in the topic. The talk is based (in part)
on the following paper:
- Huaxiong Wang and Duncan S. Wong, "On Secret Reconstruction in Secret Sharing Schemes", IEEE Transactions on Information Theory,
Vol. 54, No. 1, pp. 473-480, 2008.
- Tuesday, 14 February 2017, 11:00am-1:00pm, Room 115, 25 Exhibition Walk, Clayton Campus.
Presenter: Amin Sakzad (Monash U.)
Talk Title: Function Secret Sharing (FSS) and Splinter
Abstract: The new cryptographic tool, function secret sharing (FSS), will be introduced based on the following paper:
One of its applications, the `Splinter' protocol for practical private queries, will be discussed too:
- Elette Boyle, Niv Gilboa, and Yuval Ishai, "Function Secret Sharing", In Proceedings of EUROCRYPT 2015. Available at the following link.
- Frank Wang, Catherine Yun, Shafi Goldwasser, Vinod Vaikuntanathan, and Matei Zaharia, "Splinter: Practical Private Queries on Public Data", In Proceedings of 14th USENIX Symposium on Networked Systems Design and Implementation (NSDI'17). Available at the following link.
- Tuesday, 31 January 2017, 11:00am-1:00pm, Room 115, 25 Exhibition Walk, Clayton Campus.
Presenter: Ron Steinfeld (Monash U.)
Abstract: We'll discuss the `Blind Seer' protocol for search on encrypted databases:
- Vasilis Pappas, Fernando Krell, Binh Vo, Vladimir Kolesnikov, Tal Malkin, Seung Geol Choi, Wesley George, Angelos D. Keromytis, and Steven M. Bellovin, "Blind Seer: A Scalable Private DBMS" In Proceedings of the 35th IEEE Symposium on Security & Privacy (S&P), May 2014, San Jose, CA. Available at the following link.
- Friday, 12 September 2014, 2:00pm-3:30pm, Room G12A, Building 26. At this meeting, we'll discuss a recent paper on privacy-preserving cloud-based search:
- B. Yao, F. Li, X. Xiao. Secure Nearest Neighbor Revisited. Available here.
- Thursday, 24 July 2014, 4:30pm-5:30pm, Room 115, Building 63. At this meeting, we'll look at a nice application of
cryptographic multilinear maps (discussed last time) to construct efficient broadcast encryption schemes.
The constructions are described in the following paper (to be presented at Crypto 2014):
- D. Boneh, B. Waters and M. Zhandry. Low Overhead Broadcast Encryption from Multilinear Maps. Available here.
- Friday, 27 June 2014, 1:30pm-3:00pm, Room 12A, Building 26 (note unusual venue). At this meeting, we'll look at the GGH construction of cryptographic multilinear maps from ideal lattices, and some of their applications.
The GGH construction is described in the following paper (presented at Eurocrypt 2013):
- S. Garg, C. Gentry, S. Halevi. Candidate Multilinear Maps from Ideal Lattices. Available here.
- Friday, 8 Nov. 2013, 2pm-3:30pm. At this meeting (and subsequent ones), I propose we continue along the theme we began in
the previous meeting, namely looking at cryptosystems with extra functionality and their applications. For the coming meeting, we'll discuss the
following paper presented at STOC 2013. The paper gives a new technique (based on the LWE problem we discussed last time) for
building "Attribute-Based Encryption" (ABE), a powerful generalization of "Identity-Based Encryption" (IBE) that allows an encryptor
to specify a set of parameters for controlling access to decryption of ciphertexts.
- S. Gorbunov, V. Vaikuntanathan, H. Wee. Attribute-Based Encryption for Circuits. Available here.
- Friday, 27 Sep. 2013, 2pm-3:30pm. At this meeting, we'll discuss the following paper presented at the Crypto 2013 conference, which reports on progress in the design of Fully Homomorphic Encryption (FHE) schemes based on lattice problems.
- C. Gentry, A. Sahai, B. Waters. Homomorphic Encryption from Learning with Errors: Conceptually-Simpler, Asymptotically Faster, Attribute-Based. Available here.
Shabnam Kasra Kermanshahi
Wilson Alberto Torres