Kaysarul Anas Apurba

Kaysarul Anas Apurba

CV
Applied ML & LLM Security · Backend & Cloud Engineering · Software Engineer
M.Sc. Computational Sciences · Laurentian University

I am an independent ML researcher and PhD applicant with an M.Sc. in Computational Sciences from Laurentian University, Canada (CGPA 9.10/10). My work spans medical image analysis, NLP, and network security — with a focus on building systems that are both accurate and deployable in low-resource settings.

My research interests include LLM Security, Intrusion Detection, Adversarial Robustness, Information Retrieval, and Medical Image Analysis. I am currently working on RAG systems hardened against retrieval poisoning and prompt injection, and automated malaria cell segmentation from blood smear images.

I am actively engaged in several ongoing collaborative projects. For a closer look at my recent and current work, please visit my Research page.

Kaysarul Anas Apurba
News
Sep 2026
Our paper A Non-Invasive Cloud-Based Migration Strategy for Post-Quantum Cybersecurity in Smart HVAC Systems is now available on arXiv. Targeting Symmetry (MDPI).
Sep 2026
Our paper Defending Retrieval-Augmented Intrusion Detection Against Knowledge Poisoning and Prompt Injection (RAG-IDS) has been accepted to the research track at IEEE CIC 2026. Preprint available on arXiv. A journal extension is planned.
Aug 2026
Our paper A Non-Invasive Cloud-Based Migration Strategy for Post-Quantum Cybersecurity in Smart HVAC Systems has completed experiments; the first draft is in progress. We are targeting Symmetry (MDPI), with an arXiv preprint to follow.
Aug 2026
Our paper MalariAI: A Label-Resilient Decoupled Framework for Annotation-Agnostic Cell Segmentation and Explainable Stage Classification in Dense Malaria Blood Smears has been submitted to Array (Elsevier) and is available on arXiv.
Aug 2026
SciRet: A Compute-Aware Empirical Study of Retrieval and Reranking for Scientific RAG is now available on arXiv. Targeting COLING 2027 (ARR Cycle 2) as a short paper.
Jul 2026
Won 3rd Place Overall at CU Hacking 2026 (Ottawa) with BioReact-Pi — an edge-AI bioreactor controller on Raspberry Pi!
Jun 2026
Won 2nd Place and Best Use of NVIDIA at Cursor Hackathon Sudbury 2026 with our project, Northern Shift Guard!
Apr 2025
Graduation: Successfully completed my M.Sc. In Computational Sciences at Laurentian University, Canada (CGPA 9.10/10).
Apr 2025
Award: Received the Mabel Jean and Bob Lye Memorial Award (2024) — Laurentian University.
Sep 2023
Masters Study: Started my Masters In Computational Sciences at Laurentian University, Canada.
Selected Publications View all publications
Symmetry A Non-Invasive Cloud-Based Migration Strategy for Post-Quantum Cybersecurity in Smart HVAC Systems: Architecture, Implementation, and Empirical Evaluation
A Non-Invasive Cloud-Based Migration Strategy for Post-Quantum Cybersecurity in Smart HVAC Systems: Architecture, Implementation, and Empirical Evaluation

Mahedee Zaman Moon1, Kaysarul Anas Apurba2, Md. Hasibul Hasan3, Sk. Md. Mizanur Rahman*

Symmetry (MDPI) Targeting Symmetry Preprint 2026

Legacy smart HVAC systems suffer from critical quantum vulnerabilities due to their reliance on classical ECDH. We propose a non-invasive, cloud-based proxy architecture that integrates NIST-standard post-quantum cryptography (ML-KEM and ML-DSA) into the ecosystem without modifying legacy hardware or firmware, providing a deployable migration pathway to quantum-safe security.

Legacy smart HVAC controllers rely on vendor-cloud TLS secured by ECDH and RSA, both broken by Shor's algorithm, and typical 10–15 year lifespans mean today's devices remain in service through the quantum-threat era. Direct on-device post-quantum cryptography is infeasible: an ESP32-S3, representative of capable HVAC hardware, has only 339 KB free heap against the 900 KB ML-KEM-768 requires, and even classical ECDH-P256 keygen (111.93 ms) dwarfs hardware AES-128 (0.032 ms). We propose a non-invasive PQC proxy, requiring no device, firmware, or vendor-cloud changes, performing ML-KEM-768 encapsulation and ML-DSA-65 authentication (NIST FIPS 203/204) with AES-256-GCM session keys via HKDF, implemented with Open Quantum Safe liboqs on a Raspberry Pi 4B gateway. Over 500 runs, the post-quantum handshake (Steps 1–6) completes in 2.48 ms, 0.38 ms slower than classical baseline, with PQC computation around 8% of handshake time at 20 ms simulated round-trip network latency. The gateway sustains 443 sessions/second, 100% success under 32 concurrent connections, extrapolating to 3,546 sessions/second on a 32-core cloud instance. Five side-channel tests, including verified in-place session-key zeroization and a fixed-vs-random TVLA timing analysis, found no exploitable timing leakage or susceptibility to man-in-the-middle attacks. The architecture is vendor-agnostic and becomes unnecessary once vendors adopt NIST PQC natively.

IEEE CIC
Defending Retrieval-Augmented Intrusion Detection Against Knowledge Poisoning and Prompt Injection

Kaysarul Anas Apurba1, Md. Hasibul Hasan, Mahedee Zaman Moon, Sk. Md. Mizanur Rahman*, Atsuo Inomata

The 12th IEEE International Conference on Collaboration and Internet Computing (IEEE CIC 2026) Accepted Accepted 2026

Retrieval-Augmented Generation (RAG) enables large language models to classify network flows and generate human-readable incident reports by retrieving semantically similar historical traffic from a vector knowledge base. However, the retrieval layer introduces vulnerabilities to knowledge poisoning and prompt-injection attacks. We present RAG-IDS, a three-tier multi-agent intrusion detection framework with a retrieval-boundary defense combining soft trust scoring, label-embedding consistency checking (LECC), and prompt sanitization designed to recover classification quality under retrieval-layer attacks. Experiments on CIC-UNSW-NB15 show recovery relative to clean undefended performance ranging from R=1.0 at 1% poisoning to R=0.57 at 30%, with negligible clean-performance overhead. Under prompt injection, multi-document retrieval limits label-flip success to 0.6–2.4%, compared with 35–55% for single-document retrieval. Ablation results show that LECC is the primary contributor to robustness, while soft trust-based demotion outperforms hard filtering. The defended RAG pipeline offers an explainable, attack-resilient foundation for intrusion detection, well suited for hybrid deployment alongside high-throughput classifiers.

Array MalariAI: A Label-Resilient Decoupled Framework for Annotation-Agnostic Cell Segmentation and Explainable Stage Classification in Dense Malaria Blood Smears
MalariAI: A Label-Resilient Decoupled Framework for Annotation-Agnostic Cell Segmentation and Explainable Stage Classification in Dense Malaria Blood Smears

Kaysarul Anas Apurba, Md Hasibul Hasan, Mohammad Ali, Tanzilur Rahman*

Array (Elsevier) 2026

We present MalariAI, a two-stage decoupled framework for annotation-agnostic cell segmentation and explainable stage classification in dense malaria blood smears. Stage 1 applies distance-transform watershed to recover 75.95% of ground-truth cells without any annotation input; end-to-end binary parasitized AP@0.5 reaches 29.10% (multi-class mAP@0.5: 8.67%). Stage 2 fine-tunes EfficientNet-B0 with Focal Loss to 98.36% crop classification accuracy, with 87.5% and 75.0% on the rare schizont and gametocyte stages. Grad-CAM++ heatmaps provide per-cell spatial evidence for clinical audit, confirmed by energy-in-box analysis (+0.0485, paired p = 1.4×10⁻³³). Evaluated on NIH BBBC041 with zero-shot transfer to MP-IDB.

TENSYMP
Accurate Prediction of Pulmonary Fibrosis Progression Using EfficientNet and Quantile Regression: A High Performing Approach

Rofiqul Alam Shehab, Kaysarul Anas Apurba, Md. Ahsanuzzaman, Tanzilur Rahman*

IEEE Region 10 Symposium (TENSYMP 2023) Conference 2023

Accurate prediction of pulmonary fibrosis progression is crucial for effective patient management. This study proposes an efficient deep learning framework for predicting the progression of pulmonary fibrosis using high-resolution computed tomography (HRCT) images. We leverage the EfficientNet architecture, known for its high accuracy and computational efficiency, to extract discriminative features from CT scans. To capture the uncertainty inherent in disease progression, we employ quantile regression instead of standard mean-based regression. This approach allows us to model the conditional distribution of future lung function, providing not only a point prediction but also prediction intervals that quantify the uncertainty associated with the prognosis. Our experiments on a benchmark dataset demonstrate that the proposed EfficientNet-based quantile regression model achieves state-of-the-art performance, outperforming existing methods in predicting pulmonary fibrosis progression while providing reliable uncertainty estimates.