About Me
Hi! My name is Dr Rachel Player and I’m a Senior Lecturer in the Department of Information Security at Royal Holloway, University of London. In 2020-2021, I was a visiting researcher at The Alan Turing Institute. Before that, I was a visiting researcher and a postdoctoral researcher in the PolSys team of LIP6 at Sorbonne Université in Paris. I obtained my PhD from Royal Holloway in 2018. I rejoined Royal Holloway as a postdoctoral researcher in January 2019, then became a lecturer in November 2019, and then senior lecturer in June 2024.
My main research interests are post-quantum cryptography, especially lattice-based cryptography, and homomorphic encryption. I am also interested in the application of quantum algorithms in cryptanalysis. In 2019 I was honoured by Internet Security Research Group with The Radiant Award for Advancing Internet Security.
I am currently on sabbatical from teaching. In the 2023-2024 academic year, I was the module leader of IY3660 Applications of Cryptography. In 2019-2023, I was the module leader of IY3501 Security Management. I have also supervised BSc and MSc projects in Information Security. In 2022, I received a College Excellence Teaching Commendation.
Publications
On Algebraic Homomorphic Encryption and its Applications to Doubly-Efficient PIR
Hiroki Okada, Rachel Player, Simon Pohmann, Christian Weinert. Preprint.
A Central Limit Framework for Ring-LWE Decryption
Sean Murphy, Rachel Player. IACR Communications in Cryptology. Volume 1, No. 2, 2024.
BCH+24
eprint.iacr.org/2024/960Designs for practical SHE schemes based on Ring-LWR
Madalina Bolboceanu, Anamaria Costache, Erin Hales, Rachel Player, Miruna Rosca, Radu Titiu. Preprint. Accepted presentation at FHE.org 2024.
Security Guidelines for Implementing Homomorphic Encryption
Jean-Philippe Bossuat, Rosario Cammarota, Jung Hee Cheon, Ilaria Chillotti, Benjamin R. Curtis, Wei Dai, Huijing Gong, Erin Hales, Duhyeong Kim, Bryan Kumara, Changmin Lee, Xianhui Lu, Carsten Maple, Alberto Pedrouzo-Ulloa, Rachel Player, Luis Antonio Ruiz Lopez, Yongsoo Song, Donggeon Yhee, Bahattin Yildiz. Preprint. Accepted presentation at FHE.org 2024.
Towards Practical Doubly-Efficient Private Information Retrieval
Hiroki Okada, Rachel Player, Simon Pohmann, Christian Weinert. Proceedings of Financial Cryptography 2024, to appear.
Homomorphic polynomial evaluation using Galois structure and applications to BFV bootstrapping
Hiroki Okada, Rachel Player, Simon Pohmann. Advances in Cryptology – ASIACRYPT 2023, Proceedings, Part VI, pages 69-100, 2023.
On the precision loss in approximate homomorphic encryption
Anamaria Costache, Benjamin R. Curtis, Erin Hales, Sean Murphy, Tabitha Ogilvie, Rachel Player. SAC’23, Selected Areas in Cryptography, Proceedings, pp 325-345, 2023.
Optimisations and tradeoffs for HElib
Anamaria Costache, Lea Nürnberger, and Rachel Player. CT-RSA’23, Cryptographers’ Track at the RSA Conference 2023, Proceedings, pages 29-53, 2023.
BCPR22
eprint.iacr.org/2023/010Verifying Classic McEliece - examining the role of formal methods in post-quantum cryptography standardisation
Martin Brain, Carlos Cid, Rachel Player, Wrenna Robson. Code-Based Cryptography - 10th International Workshop, CBCrypto’22, Revised Selected Papers, pages 21-36, 2022.
Discretisation and Product Distributions in Ring-LWE
Sean Murphy, Rachel Player. Journal of Mathematical Cryptology. Volume 15, Issue 1, pages 45–59, 2021.
Improved privacy-preserving training using fixed-Hessian minimisation
Tabitha Ogilvie, Rachel Player, Joe Rowell. 8th Workshop on Encrypted Computing & Applied Homomorphic Cryptography, WAHC 2020, pages 6—18, 2020.
Evaluating the effectiveness of heuristic worst-case noise analysis in FHE
Anamaria Costache, Kim Laine, Rachel Player. 25th European Symposium on Research in Computer Security, ESORICS 2020, Proceedings, Part II, pages 546-565.
On the Feasibility and Impact of Standardising Sparse-secret LWE Parameter Sets for Homomorphic Encryption
Benjamin R. Curtis, Rachel Player. 7th Workshop on Encrypted Computing & Applied Homomorphic Cryptography, WAHC@CCS 2019, pages 1-10, 2019.
BGPT19
eprint.iacr.org/2019/389Achieving secure and efficient lattice-based public-key encryption: the impact of the secret-key distribution
Sauvik Bhattacharya, Oscar Garcia-Morchon, Rachel Player, Ludo Tolhuizen. Preprint.
δ-subgaussian random variables in cryptography
Sean Murphy, Rachel Player. 24th Australasian Conference on Information Security and Privacy, ACISP 2019, Proceedings, pages 251-268, 2019.
Estimate all the {LWE,NTRU} schemes!
Martin R. Albrecht, Benjamin R. Curtis, Amit Deo, Alex Davidson, Rachel Player, Eamonn W. Postlethwaite, Fernando Virdia, Thomas Wunderer. Security and Cryptography for Networks - 11th International Conference, SCN 2018, Proceedings, pages 351-367, 2018. Check out the project webpage.
CLPX18
eprint.iacr.org/2017/809High-Precision Arithmetic in Homomorphic Encryption
Hao Chen, Kim Laine, Rachel Player, Yuhou Xia. Topics in Cryptology – CT-RSA 2018, Proceedings, pages 116–136, 2018.
Simple Encrypted Arithmetic Library – SEAL v2.1
Hao Chen, Kim Laine, Rachel Player. Financial Cryptography and Data Security – FC 2017 International Workshops, WAHC, BITCOIN, VOTING, WTSC, and TA, Revised Selected Papers, pages 3–18, 2017.
BGPW16
eprint.iacr.org/2016/089On the Hardness of LWE with Binary Error - Revisiting the Hybrid Lattice-Reduction and Meet-in-the-Middle Attack
Johannes Buchmann, Florian Göpfert, Rachel Player, Thomas Wunderer. Progress in Cryptology – AFRICACRYPT 2016, pages 24–43, 2016.
On the concrete hardness of Learning with Errors
Martin R. Albrecht, Rachel Player, Sam Scott. Journal of Mathematical Cryptology. Volume 9, Issue 3, Pages 169–203, 2015. Check out the LWE Estimator and the more recent Lattice Estimator.
Talks
- 6 June 2024. On the precision loss in approximate homomorphic encryption. FPBench Community Meeting, virtual.
- 25 May 2024. Security Guidelines for Implementing Homomorphic Encryption. FHE:IDEAs (Interesting Directions and Emerging Applications), Zurich, Switzerland
- 17 August 2023. On the precision loss in approximate homomorphic encryption. SAC 2023 conference presentation, Fredericton, Canada
- 9 June 2023. New results in BFV-type FHE schemes. London Crypto Day, Royal Holloway, University of London, UK
- 5 October 2022. Homomorphic encryption: an introduction. ETSI Security Conference, Virtual
- 26 September 2022. Algorithms for the Learning with Errors problem. Quantum Cryptanalysis Workshop. University of Bristol, UK
- 2 September 2022. Updates on FHE Security standardisation efforts. 5th HE.org meeting, Geneva, Switzerland
- 5 July 2022. Noise analysis in homomorphic encryption. ACCESS seminar, Virtual
- 5 July 2022. Noise analysis in homomorphic encryption . ISG open day, Royal Holloway, University of London, UK
- 27 May 2022. Noise analysis in homomorphic encryption . Crypto Colloquium, NTNU, Norway
- 19 August 2021. Homomorphic encryption: Recent results and next steps. SIAM Conference on Applied Algebraic Geometry, Virtual
- 25 January 2021. Homomorphic encryption: An introduction. The Alan Turing Institute, Defence & Security Monthly Meetup, Virtual
- 14 December 2020. Homomorphic encryption: Recent results and next steps. ACE CSR Winter School, Virtual
- 14 July 2020. Security and noise growth in homomorphic encryption. MSR Cryptography Colloquium, Virtual
- 7 February 2020. Security and noise growth in HE: Recent results and next steps. Homomorphic Encryption Standardization Strategic Planning Meeting, Microsoft Research, Redmond, USA
- 16 December 2019. Homomorphic noise growth in practice. IMA International Conference on Cryptography and Coding, Oxford, UK
- 6 December 2019. Evaluating the effectiveness of heuristic worst-case noise analysis in FHE. DS Lunch Colloquium, Radboud University, Nijmegen
- 2 December 2019. Evaluating the effectiveness of heuristic worst-case noise analysis in FHE. COSIC Seminar, KU Leuven, Belgium
- 18 October 2019. On the condition number of Macaulay matrices. Dagstuhl Seminar on Quantum Cryptanalysis, Germany
- 18 August 2019. Discretisation and Product Distributions in Ring-LWE. MathCrypt 2019 workshop presentation, Santa Barbara, USA
- 3 July 2019. δ-subgaussian Random Variables in Cryptography. ACISP 2019 conference presentation, Christchurch, New Zealand
- 2 May 2019. δ-subgaussian Random Variables in Cryptography. PROMETHEUS meeting, CWI, Amsterdam
- 26 February 2019. Homomorphic Encryption: State of the art and applications. Invited seminar at Cryptosense, Paris, France
- 10 August 2018. Security and encoding in Fully Homomorphic Encryption. Seminar at the Turing, Turing Institute, London, UK
- 18 July 2018. Homomorphic Encryption: State of the art and applications. Invited talk at Workshop on Privacy Enhancing Technologies, Royal Society, London, UK
- 18 April 2018. High-Precision Arithmetic in Homomorphic Encryption. CT-RSA Conference presentation, San Francisco, USA
- 12 April 2018. Estimate all the {LWE,NTRU} schemes!. Invited talk at First PQC standardization conference, Fort Lauderdale, USA
- 9 March 2018. Estimate all the {LWE,NTRU} schemes!. Quantum-safe cryptography seminar, Sorbonne Université, Paris, France
- 29 September 2017. Parameter selection in Ring-LWE-based FHE. Lattice coding & crypto meeting, Imperial College, London, UK
- 21 April 2017. Parameter selection for security and correctness in FHE. Microsoft Research, Redmond, USA
- 7 April 2017. Simple Encrypted Arithmetic Library – SEAL. WAHC’17 conference presentation, Sliema, Malta
- 2 February 2017. Simple Encrypted Arithmetic Library – SEAL. PhD Student Seminar, Royal Holloway, University of London, UK
- 7 September 2016. Simple Encrypted Arithmetic Library – SEAL. Workshop on lattice-based cryptography with Kyushu University, Royal Holloway, University of London, UK
- June 2016. On the concrete hardness of Learning with Errors. Crypto group lunch, Microsoft Research, Redmond, USA
- 29 February 2016. On the hardness of LWE with binary error. Workshop on cyber security, Kyushu University, Japan
- 4 November 2015. On the concrete hardness of Learning with Errors. Cryptography seminar, University of Oxford, UK
- 25 May 2015. On the concrete hardness of Learning with Errors. Presentation at ICMS Workshop, Edinburgh, UK
- 26 March 2015. On the concrete hardness of Learning with Errors. CROSSING student seminar, TU Darmstadt, Germany
- 12 March 2015. On the concrete hardness of Learning with Errors. ISG Seminar, jointly with Sam Scott, Royal Holloway, University of London, UK
- 20 February 2015. On the concrete hardness of Learning with Errors. Cryptography group seminar, University of Bristol, UK
Experience
Department of Information Security, Royal Holloway, UK
June 2024 - present
Senior Lecturer
I am a Senior Lecturer in the Department of Information Security. For my latest research results, see my dblp and Google Scholar entries.
Service:
- Co-organiser of 7th HES Meeting, 13 Oct 2024.
- Co-organiser of ICMS Workshop on Foundations and Applications of Lattice-based Cryptography, 25 - 28 July 2022.
- Programme co-chair of WAHC 2021
- Programme committee of ArcticCrypt 2025, Asiacrypt 2024, CFAIL 2023, PKC 2023, PQCrypto (2022, 2021, 2020), FHE.org (2025, 2024, 2023, 2022), PPML 2021, WAHC (2023, 2020, 2019), IMACC 2019, MathCrypt 2019.
- Reviewer for CCS 2022, Asiacrypt (2020, 2016), Crypto 2020, Eurocrypt (2022, 2019), PQCrypto (2019, 2017), NutMiC 2019, ISIT 2019, MathCrypt 2018, SAC 2018, PKC 2017, IMACC 2017, CT-RSA 2015
- Committee member of Wisdom
ISG, Royal Holloway, UK
November 2019 - May 2024
Lecturer
I was a Lecturer in the Department of Information Security.
ISG, Royal Holloway, UK
January 2019 - October 2019
Postdoctoral researcher
I was a postdoc in the Information Security Group working with Martin R. Albrecht as part of the EU H2020 PROMETHEUS project on lattice-based cryptography.
LIP6, Paris, France
February 2018 - December 2018
Postdoctoral researcher
I was a postdoc in the PolSys group of LIP6 which is common between Sorbonne Université, CNRS and INRIA. I worked with Jean-Charles Faugère and Ludovic Perret on post-quantum cryptography as part of the RISQ project.
Microsoft Research, Redmond, USA
April - July 2016
Intern
I interned in the Cryptography Group where my mentor was Kim Laine. The goal of my internship was to implement the BFV scheme in Microsoft SEAL. In June 2016, we released this as SEAL v2.0.
Education
Royal Holloway, University of London
2013 - 2018
Information Security (PhD)
I obtained my PhD in the Information Security Group where I was supervised by Carlos Cid and Sean Murphy. A major focus of my research was on the concrete security of the Learning with Errors problem and its variants. My thesis investigates parameter selection in lattice-based cryptography.
University of Warwick
2009 - 2013
Mathematics (MMath, Hons)
I graduated with First Class Honours from an undergraduate Masters degree in mathematics. My MMath research project, in the area of Number Theory, was featured in the undergraduate prospectus!