shor

Factor composite integers via quantum period finding and classical post-processing.

30|2|Updated Apr 16, 2026
One-click install
npx skills add https://github.com/unitarylab/quantum-skills --skill shor
Or copy as Structured Prompt for Agent▼
Please help me install this Agent Skill.
Skill: shor
Source: https://github.com/unitarylab/quantum-skills/tree/main/algorithms/cryptography/shor
Command: npx skills add https://github.com/unitarylab/quantum-skills --skill shor

SYSTEM DOCUMENTATION & REQUIREMENTS

💡 This Skill requires unitarylab, and includes scripts (resource) components.

What problem does it solve?

Shor's algorithm factors a given composite integer efficiently by reducing factoring to quantum period finding and classical post-processing.

Core Features & Use Cases

  • Quantum period finding using QPE and IQFT to derive the order r.
  • Two circuit implementations: matrix-based modular exponentiation and operator-based modular addition.
  • Classical post-processing with continued fractions to extract factors and a retry mechanism for challenging cases.
  • Educational and demonstrative use: factor small integers like 15 or 21 to illustrate the workflow.

Quick Start

Use a small factoring example with N=15 using the matrix method to observe factors.

Frequently Asked Questions about shor

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How does quantum period finding work for integer factorization?▼

Quantum period finding uses Quantum Phase Estimation and Inverse Quantum Fourier Transform to derive the order r, reducing factoring to classical post-processing with continued fractions and gcd to extract factors.

How do I factor small integers using Shor's algorithm in Python?▼

You can factor small integers like N=15 by running a Python pipeline with modular exponentiation circuits, followed by continued fractions and a retry loop to handle challenging cases and extract factors.

What is the difference between matrix-based and operator-based circuits for modular exponentiation?▼

Matrix-based modular exponentiation and operator-based modular addition are two circuit implementation methods provided for quantum period finding, offering distinct approaches to building the modular exponentiation step.

Can I use this for simulating quantum factorization on larger numbers?▼

This implementation is applicable to educational demonstrations and research prototyping of modular exponentiation and QPE-based period finding, targeting simulations on small integers rather than large-scale factoring.

Why does quantum factorization fail to find factors on some attempts?▼

Quantum factorization may fail on certain attempts due to challenging period results, which is why the pipeline includes a classical retry loop to re-attempt factor extraction using continued fractions and gcd.