QKDpy Documentation

Welcome to the documentation for QKDpy, a Python library for Quantum Key Distribution simulation at the intersection of Space Technology, Quantum Computing, AI/ML, and Enterprise Compliance.

Status & Scope. QKDpy is a research / educational simulator. It models QKD protocols, channels, and attacks with phenomenological approximations. It is not validated for securing real key material and not a hardened, standards-compliant codec. See the Status & Scope section in the README for the precise maturity level.

Key Capabilities

Domain	Features
Satellite QKD	Satellite-ground links, free-space optical channels, orbital mechanics, atmospheric modeling
QKD Protocols	10+ protocols (BB84, E91, CV-QKD, HD-QKD, B92, SARG04, SixState, DI-QKD)
Density Matrix	Mixed-state simulation, partial trace, fidelity, entropy, purity, CPTP channels (depolarizing, amplitude damping, Kraus channel composition)
Circuit Composer	Quantum circuit construction, gate composition, Bell state preparation, OpenQASM 2.0 export, simulation
Secret Key Rate	Asymptotic and finite-size secret key rate computation for BB84 and other protocols
AI/ML	Bayesian optimization, neural network predictors, anomaly detection, adaptive protocols
Enterprise	Three-tier licensing (FREE/ENTERPRISE/PREMIUM), compliance checking, HSM integration, audit logging
Observability	Structured instrumentation via OperationSpan, @instrument decorator, domain-specific events
Quantum-Safe	Crypto inventory assessment, risk scoring, phased migration roadmap (PREMIUM)

Contents

Contents:

• Installation
  • Using uv (recommended)
  • Using pip
  • Optional Extras
  • Product Tiers
  • Verify Installation
• Quick Start
  • Density Matrix & Circuit
  • Enterprise Quick Start
• API Reference
  • Setup
  • Protocols
  • SecretKeyRate — Key Rate Calculator
  • Finite Key Analysis
  • Core Quantum Stack
  • Key Management
  • Network & Satellite QKD
  • ML Optimization
  • Enterprise Features
  • Observability
  • Framework Integrations
  • Crypto
  • Configuration
• Examples
  • Advanced Protocol Usage
  • Density Matrix & Circuit
  • Secret Key Rate Computation
  • Observability & Instrumentation
  • Enterprise Compliance Checking
  • Quantum-Safe Migration Toolkit
  • Product Tier Gating
• Product Tier Model — Public Overview
  • Context
  • Decision
  • Consequences
  • Public capabilities by tier
• Observability & Instrumentation — Public Overview
  • Context
  • Decision
  • Consequences
• Roadmap — What’s Next for QKDpy
  • Themes we’re investing in
  • How we sequence the work
  • What QKDpy is not claiming

Architecture Decision Records

Design rationale for major architectural choices is captured in Architecture Decision Records. Internal ADRs (not compiled into the public site) document decisions that are primarily relevant to maintainers and contributors.

ADR	Subject
ADR-001	Product tier licensing model
ADR-002	Observability and instrumentation
ADR-003	Enterprise config audit architecture
ADR-004	HSM is a software simulation
ADR-005	Core quantum simulation stack
ADR-006	Protocol execution model (template method)

Architecture & Diagrams

The diagrams below summarize how the library is organized — from the high-level module breakdown through the protocol execution flow, the core quantum stack, key management, network / satellite links, framework integrations, the crypto & enterprise surface, the ML optimization pipeline, and the end-to-end data flow.

Diagrams:

• High-Level Architecture
• Protocol Execution Flow
• Core Quantum Stack
• Key Management Pipeline
• Network & Satellite QKD
• Integration Layer
• Crypto & Enterprise
• ML Optimization
• Data Flow
• API Surface

Indices and tables

• Index

• Module Index

• Search Page