Inferensys

Glossary

Secure Polygenic Risk Score

A privacy-preserving protocol for calculating an individual's genetic susceptibility to a disease by securely combining their genomic data with a proprietary model of aggregated variant effects using secure multi-party computation.
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PRIVACY-PRESERVING GENOMICS

What is Secure Polygenic Risk Score?

A cryptographic protocol for calculating disease susceptibility from genetic data without exposing the individual's genome or the proprietary risk model.

A Secure Polygenic Risk Score (sPRS) is a privacy-preserving protocol that computes an individual's genetic susceptibility to a specific disease by securely combining their private genomic data with a proprietary model of aggregated variant effects, ensuring that neither party reveals their sensitive input to the other. This is achieved through secure multi-party computation (MPC) techniques, such as secret sharing and garbled circuits, which allow the calculation to be performed on encrypted data.

The protocol typically involves a patient or research participant holding an encrypted genotype and a model owner holding a confidential weight vector for thousands of single nucleotide polymorphisms (SNPs). Using cryptographic primitives like Beaver triples for efficient multiplication and DReLU protocols for non-linear activation, the system computes a weighted sum without ever decrypting the raw genome or exposing the model's proprietary coefficients, enabling collaborative genomic research under strict data governance.

ARCHITECTURAL COMPONENTS

Key Features of Secure PRS

A Secure Polygenic Risk Score protocol decomposes into distinct cryptographic and bioinformatic modules that collectively ensure both input privacy and computational integrity.

01

Secret-Shared Genotype Input

The individual's genomic variants are additively secret-shared across two or more non-colluding computing servers before any computation begins. No single server ever sees the raw genotype.

  • Uses Shamir's Secret Sharing or simple additive replication
  • Input sharing occurs client-side in a trusted local environment
  • Prevents the model owner and compute parties from learning the individual's genetic predispositions
Zero
Raw Genotype Exposure
02

Proprietary Effect-Weight Model

The aggregated variant effect sizes—the intellectual property of a research institution—are also secret-shared among the computing parties. The model remains encrypted throughout the entire calculation.

  • Protects the GWAS-derived odds ratios and linkage disequilibrium matrices
  • Model weights are never reconstructed in the clear
  • Enables commercial monetization of proprietary risk models without intellectual property leakage
03

Secure Linear Combination

The core computation is a privacy-preserving dot product between the secret-shared genotype vector and the secret-shared effect-weight vector, executed using Beaver triples for efficient multiplication.

  • Leverages pre-computed multiplication triples to eliminate online cryptographic overhead
  • Implements secure truncation to manage fixed-point precision
  • Population-level normalization factors (means, standard deviations) are applied obliviously
04

Oblivious Risk Stratification

The final PRS is compared against population percentile thresholds using a secure comparison protocol (DReLU), outputting only a risk category to the authorized recipient without revealing the raw score.

  • Prevents gradient leakage or inference of the underlying model
  • Output can be a simple categorical result (e.g., 'elevated risk')
  • The individual learns their risk tier but nothing about the proprietary model's internal thresholds
05

Auditable MPC Ceremony

The entire protocol execution generates a cryptographic transcript that can be verified by a third-party auditor without revealing the private inputs, ensuring compliance with regulatory frameworks.

  • Implements verifiable secret sharing for input consistency checks
  • Provides non-repudiation for clinical decision support contexts
  • Supports integration with sovereign health data infrastructure requirements
06

Population Reference Panel Security

Ancestry-specific allele frequency and linkage disequilibrium reference panels, required for score normalization, are accessed via Private Information Retrieval (PIR) to hide which population stratum is being queried.

  • Prevents the reference panel server from learning the individual's genetic ancestry
  • Uses keyword PIR or index PIR for efficient oblivious lookups
  • Mitigates side-channel leakage through population-specific reference data access patterns
PRIVACY-PRESERVING GENOMICS

Frequently Asked Questions

Clear, technically precise answers to the most common questions about secure polygenic risk score computation, a critical intersection of cryptography and precision medicine.

A Secure Polygenic Risk Score (sPRS) is a privacy-preserving protocol that calculates an individual's genetic susceptibility to a specific disease by securely combining their private genomic data with a proprietary, aggregated model of variant effects, without revealing the raw genome to the model owner or the model weights to the individual. The computation typically leverages secure multi-party computation (MPC) or homomorphic encryption. In an MPC-based architecture, the individual's genotype and the model owner's effect-size weights are secret-shared among two or more non-colluding computing servers. These servers jointly perform a linear weighted sum—multiplying each single nucleotide polymorphism (SNP) by its corresponding effect size and summing the results—over the secret-shared values. The final risk score is reconstructed only by the authorized recipient, usually the individual or their physician. This ensures that the model owner learns nothing about the individual's genetic variants, and the individual learns nothing about the proprietary model coefficients beyond their final aggregated score.

Prasad Kumkar

About the author

Prasad Kumkar

CEO & MD, Inference Systems

Prasad Kumkar is the CEO & MD of Inference Systems and writes about AI systems architecture, LLM infrastructure, model serving, evaluation, and production deployment. Over 5+ years, he has worked across computer vision models, L5 autonomous vehicle systems, and LLM research, with a focus on taking complex AI ideas into real-world engineering systems.

His work and writing cover AI systems, large language models, AI agents, multimodal systems, autonomous systems, inference optimization, RAG, evaluation, and production AI engineering.