Q-Day and Post-Quantum Cryptography: Harvest Now, Decrypt Later, and the Migration

AdvancedFree5 modules · 15 lessons

About this course

An honest treatment of the post-quantum transition: what a cryptographically relevant quantum computer would and would not break, why harvest now, decrypt later makes long lived secrets urgent today with no settled timeline for the threat, and the standardised post-quantum algorithms, ML-KEM, ML-DSA and SLH-DSA, and what each replaces. You will learn hybrid key exchange, crypto agility applied to this specific migration, and a phased migration plan ordered by data lifetime rather than a predicted date.

What you'll learn

Understanding the Threat Honestly

What a Cryptographically Relevant Quantum Computer Is, and Is Not
Shor's Algorithm and Why Asymmetric Cryptography Falls
Grover's Algorithm and the Modest Effect on Symmetric Cryptography

Harvest Now, Decrypt Later

The Harvest Now, Decrypt Later Threat Model
Data Lifetime as the Urgency Driver, Not a Predicted Date
Who Is Exposed Today: Sectors and Data Types With Long Confidentiality Requirements

The Standardised Algorithms

ML-KEM: Post-Quantum Key Encapsulation
ML-DSA, SLH-DSA and Hash-Based Signatures
Choosing Algorithms and Parameters, and Where to Verify Them

Migration Architecture

01Understanding the Threat Honestly3 lessons

What a Cryptographically Relevant Quantum Computer Is, and Is Not
Shor's Algorithm and Why Asymmetric Cryptography Falls
Grover's Algorithm and the Modest Effect on Symmetric Cryptography

02Harvest Now, Decrypt Later3 lessons

Common questions

How much does Safeguard Academy cost?

Nothing. Every course, exam, and certificate on the catalog is free — including retakes. All you need is a free Safeguard account.

What are the prerequisites?

None. The flagship course, Safeguard Certified Practitioner, is a beginner-level course — basic familiarity with how software is built helps, but every exam question is answerable from the lessons themselves.

Hybrid Key Exchange During the Transition

Crypto Agility as an Architectural Property, Applied to This Migration

Certificates, Protocols and Public Key Infrastructure in a Post-Quantum World

Building the Migration Plan

Inventory First: Classifying Data by Lifetime
A Phased Migration Plan: Pilot, Hybrid Rollout, Cutover, Decommission
Governance, Vendor Questions and Tracking Readiness

The Harvest Now, Decrypt Later Threat Model

Data Lifetime as the Urgency Driver, Not a Predicted Date

Who Is Exposed Today: Sectors and Data Types With Long Confidentiality Requirements

03The Standardised Algorithms3 lessons

ML-KEM: Post-Quantum Key Encapsulation
ML-DSA, SLH-DSA and Hash-Based Signatures
Choosing Algorithms and Parameters, and Where to Verify Them

04Migration Architecture3 lessons

Hybrid Key Exchange During the Transition
Crypto Agility as an Architectural Property, Applied to This Migration
Certificates, Protocols and Public Key Infrastructure in a Post-Quantum World

05Building the Migration Plan3 lessons

Inventory First: Classifying Data by Lifetime
A Phased Migration Plan: Pilot, Hybrid Rollout, Cutover, Decommission
Governance, Vendor Questions and Tracking Readiness

What happens if I fail the exam?

You can retake it after a 24-hour cooldown, as many times as you need. Retakes are free, and each attempt draws a fresh random set of questions.

How long is a certificate valid?

The Safeguard Certified Practitioner credential is valid for 24 months from issue. The expiry date is printed on the certificate and shown live on its public verification page. Renewing means passing the current exam again.