Reference
Quantum Risk Governance Glossary
Ninety-six terms that define how the Quantum Core Institute, publisher of QCI-QS1, talks about quantum risk: the threat, the standards, the algorithms, the identity surface, the regulatory map, the horizon, and the documents that turn it into a mandate. Every term is deep-linkable — copy any heading's anchor and cite it.
Foundational Threat Concepts
The vocabulary boards need to understand why quantum is a present-tense liability, not a future technology problem. These terms anchor every conversation about exposure, timing, and risk acceptance.
CRQC (Cryptographically Relevant Quantum Computer)#
- A quantum computer sufficiently powerful to break existing cryptographic systems. The NCSC notes PQC algorithms are "specifically designed to be resistant against a CRQC".
Cryptographic Debt#
- The accumulated technical debt from deferred cryptographic upgrades, algorithm deprecations, and unmanaged key material. A measurable liability for risk registers.
Harvest Now, Decrypt Later (HNDL)#
- An active threat where adversaries collect encrypted data today with the expectation of decrypting it once quantum capability arrives. This transforms every current communication into a time-dependent vulnerability.
Legacy Crypto Lock-in#
- A governance failure where organizations cannot replace cryptographic components because algorithms are hardcoded, undocumented, or embedded in vendor products without upgrade paths.
Long-lived Data Exposure#
- The vulnerability of data requiring confidentiality beyond the expected arrival of Q-Day. Any data with >10-year retention is currently exposed under HNDL threat models.
Q-Day#
- The point at which a quantum computer capable of breaking current public-key cryptography exists. Boards should treat Q-Day not as a technology event but as a liability event.
Quantum Advantage (for attackers)#
- The point at which quantum computers can solve cryptographic problems faster than classical computers, rendering current key lengths insufficient. Distinct from "quantum advantage" in scientific computing.
Quantum Risk#
- The enterprise exposure arising from the potential for cryptographically relevant quantum computers to break existing public-key cryptography, encompassing data confidentiality, identity integrity, and transaction non-repudiation surfaces as defined in QCI-QS1.
Quantum-Safe Horizon#
- The timeframe (typically 5–15 years) within which organizations must complete cryptographic migration before CRQCs become operational. A board-level planning parameter.
Temporal Cybersecurity Risk#
- A risk model where data's vulnerability increases over time as decryption capability approaches. HNDL makes confidentiality a function of time and data retention policy.
Governance & Standards
The frameworks, scores, and artifacts that turn quantum risk into something a board can actually oversee. QCI-QS1 and the Q-Risk Score sit at the centre of this layer.
Algorithm Deprecation Management#
- The governance process for phasing out cryptographic algorithms as they weaken, including timelines, fallback provisions, and compliance verification.
CBOM (Cryptographic Bill of Materials)#
- A structured, machine-readable inventory describing all cryptographic assets used by a system: algorithms, parameters, keys, certificates, trust stores, crypto libraries, and protocols. An extension of SBOM specifically for PQC migration.
Crypto-Agility#
- The organizational capability to systematically manage cryptographic assets and modify, replace, or upgrade any component of the cryptographic stack without operational disruption. Essential for regulatory compliance.
Cryptographic Inventory#
- The complete, verified catalog of all cryptographic assets across an organization, including algorithms, keys, certificates, libraries, protocols, and their dependencies. Pre-requisite for any migration.
Cryptographic Library Governance#
- The policies and processes for managing third-party crypto libraries (OpenSSL, BoringSSL, etc.) including version tracking, vulnerability monitoring, and upgrade coordination.
Cryptographic Stack#
- The full hierarchy of cryptographic components from hardware security modules through algorithms, protocols, key management, and application-layer implementations. Governance requires visibility across all layers.
Post-Quantum Cryptography (PQC)#
- Cryptographic algorithms designed to be secure against attacks from both classical and quantum computers, running on conventional hardware. The term encompasses key encapsulation mechanisms and digital signatures.
PQ/T Hybrid Scheme#
- A cryptographic implementation combining traditional (pre-quantum) and post-quantum algorithms in parallel. Standardized in IETF RFC 9794. Enables safe migration without single points of failure.
PQ/T Hybrid Terminology#
- The standardized language defined in IETF RFC 9794 for discussing hybrid cryptographic schemes. The NCSC notes consistent terminology "prevents misunderstandings that can lead to security issues".
Q-Ready Framework#
- A five-phase operational roadmap for quantum readiness: Discovery, Planning, Implementation, Validation, and Maintenance. The board-level standard for organizing PQC migration.
Q-Risk Score#
- A 0–100 quantitative measure of an organization's quantum risk posture, calculated using the QASI framework with hard ceilings at 60, 65, 70, and 80. The 65 ceiling requires a complete identity and trust-chain inventory.
QASI Framework#
- The Quantum Attack Surface Inventory framework used to categorize and measure cryptographic exposures across identity, payment, and data domains.
QCI-QS1#
- The free, citeable standard for quantum risk governance published by the Quantum Core Institute. Mapped to DORA, NIS2, NCUA, HIPAA, and FFIEC. The only governance standard covering all three risk surfaces: identity, payment, and data.
Quantum Risk Governance#
- The system of policies, standards, and oversight through which boards and management control quantum-related cryptographic risks. Distinct from "quantum security" which focuses on technical controls.
Quantum Risk Register#
- An enterprise risk management artifact where quantum-related threats are cataloged, scored, and assigned to owners. Required for board-level oversight.
Technical PQC Standards
The algorithms and mathematical foundations that will replace RSA and ECC. Most boards do not need to evaluate these, but every CTO needs to know which ones are standardized, which are diversification options, and why hash-based signatures matter.
Code-Based Cryptography#
- A PQC family based on decoding random linear error-correcting codes. The McEliece cryptosystem (1978) is the oldest unbroken public-key scheme. Selected by NIST for diversification (HQC).
FN-DSA#
- A lattice-based signature scheme based on FALCON. Produces significantly smaller signatures than ML-DSA, ideal for certificate chains and embedded systems. Under NIST standardization.
Grover's Algorithm#
- A quantum search algorithm that provides quadratic speedup for brute-force attacks, effectively halving symmetric key strength (AES-256 becomes AES-128 equivalent).
Hash-Based Signatures#
- Digital signature schemes relying solely on cryptographic hash functions for security. SLH-DSA is the NIST-standardized example. Offers security independent of number-theoretic assumptions.
KEM (Key Encapsulation Mechanism)#
- A cryptographic primitive allowing secure shared secret establishment using a recipient's public key. Has largely replaced traditional key exchange in PQC due to simpler security proofs.
Lattice-Based Cryptography#
- The most prominent family of PQC algorithms, securing three of NIST's four initial standards. Security relies on mathematical problems involving high-dimensional lattices, particularly LWE.
Learning With Errors (LWE)#
- The core mathematical problem underpinning most lattice-based PQC. Module-LWE (structured variant) forms the basis of ML-KEM and ML-DSA.
ML-DSA (FIPS 204)#
- NIST's primary post-quantum digital signature standard based on CRYSTALS-Dilithium. Provides authentication for software updates, certificates, and signed data.
ML-KEM (FIPS 203)#
- NIST's primary post-quantum key encapsulation standard based on CRYSTALS-Kyber. Enables two parties to establish a shared secret securely. Three parameter sets: -512, -768, -1024.
NIST PQC Standardization#
- The multi-round competition launched 2016 to evaluate PQC algorithms. Published first three standards August 2024. The single most influential program shaping global quantum-safe transition.
Post-Quantum Encryption (PQE)#
- The broader term specifically emphasizing the application of quantum-resistant algorithms to encrypt data. PQE represents the solution layer, whereas PQC refers to the algorithm layer.
PQC Algorithm Substitution#
- The process of replacing vulnerable algorithms (RSA, ECC) with NIST-standardized PQC algorithms (ML-KEM, ML-DSA). Requires complete cryptographic inventory as prerequisite.
Quantum Decryption#
- The process of using quantum computational capabilities to break encrypted data. The core capability enabling HNDL attacks when CRQCs become available.
Shor's Algorithm#
- The quantum algorithm that efficiently factors large integers, breaking RSA encryption. The reason current public-key cryptography becomes obsolete with sufficiently powerful quantum computers.
SLH-DSA (FIPS 205)#
- A stateless hash-based signature scheme whose security relies solely on hash function properties. Larger signatures but fundamentally different security assumptions than lattice schemes. Critical diversification option.
Identity & Machine Credentials
Identity is the surface most boards underestimate. Machine identities outnumber humans by orders of magnitude, every certificate chain has quantum-vulnerable links, and a forged signature in this layer is indistinguishable from a legitimate one.
Certificate Authority (CA) Quantum Readiness#
- The preparedness of certificate authorities to issue PQC certificates. A supply chain risk for all organizations using digital certificates.
Certificate Chain Vulnerability#
- The exposure arising when any certificate in a trust chain uses vulnerable algorithms. Quantum breaks any link, collapsing whole chain security.
Credential Rotation#
- The process of regularly changing authentication credentials. Machine identities often have automated rotation (e.g., 90-day certificate expiry), creating coordination requirements.
Device Identity#
- A machine identity representing physical or virtual devices (computers, mobile devices, IoT sensors). Frequently overlooked in cryptographic inventories.
Federated Identity Credential (FIC)#
- A configuration allowing external identity providers to access resources without secret management. Creates complex trust chains requiring governance.
Identity Risk Surface#
- The collection of all identity-related cryptographic vulnerabilities including certificate chains, signing keys, authentication systems, and machine credentials. One of QCI's three risk surfaces.
Machine Credential Sprawl#
- The uncontrolled proliferation of undocumented machine identities, service accounts, and API keys. Primary governance failure in identity risk management.
Machine Identity#
- Non-human identities including devices, workloads, applications, services, and AI agents. Each represents an automated entity requiring authentication. Often uncounted in inventories.
Non-Repudiation in Quantum Era#
- The ability to prove who performed what action when quantum computers can forge digital signatures. Payment risk surface as defined in QCI-QS1.
Private Key Compromise (Quantum)#
- The exposure of private keys through quantum-capable cryptanalysis rather than theft or leakage. Requires complete key replacement, not just revocation.
Service Principal#
- The local representation of an application in an identity provider. All managed identities have service principals, creating an overlooked attack surface.
Trust Chain Inventory#
- The complete catalog of all certificate authorities, intermediate CAs, and root certificates trusted by an organization. Required for the QCI-QS1 65 ceiling score.
Workload Identity#
- A category of machine identity representing software workloads (applications, service principals, managed identities). Requires same governance rigor as human identities.
X.509 Certificate Post-Quantum Migration#
- The process of replacing traditional certificates with PQC certificates in PKI infrastructure. Requires CA coordination and client compatibility validation.
Data, Payments & Regulatory Compliance
Where quantum risk meets the regulators. These terms tie cryptographic exposure to the obligations boards already report against — DORA, NIS2, NCUA, FFIEC, SEC.
Cryptographic Compliance Gap#
- The measurable difference between current cryptographic posture and regulatory requirements for PQC. A quantifiable metric for board reporting.
Data Longevity Classification#
- A governance system categorizing data by required confidentiality duration. Determines which data is exposed under HNDL and which can wait for migration.
DORA (Digital Operational Resilience Act)#
- EU regulation requiring financial entities to manage ICT risk including quantum threats. QCI-QS1 maps directly to DORA requirements.
FFIEC Quantum Guidance#
- Federal Financial Institutions Examination Council expectations for quantum risk management in banking. QCI-QS1 alignment documented.
NCUA PQC Requirements#
- National Credit Union Administration guidance on quantum readiness for credit unions. QCI-QS1 provides compliance framework.
NIS2 Directive#
- EU cybersecurity legislation expanding coverage to more sectors. Requires quantum risk consideration in security policies. Mapped to QCI-QS1.
Payment Risk Surface#
- The collection of transaction-related cryptographic vulnerabilities including settlement systems, payment signing, audit trails, and counterparty verification. Governed by QCI-QS1 Clause 7.
PQC Audit Trail#
- Documentary evidence of cryptographic migration decisions, including timing rationales and risk acceptance. Required for regulatory defense.
Quantum Assurance Evidence#
- The recorded justification for "wait" decisions on specific risk surfaces. QCI records all recommendations as defendable evidence.
SEC Disclosure Obligation#
- The requirement to disclose material quantum risks in financial filings if exposure could impact operations or financial condition.
Transaction Integrity Risk#
- The vulnerability that forged digital signatures could invalidate payment audit trails and legal enforceability. The unbounded scenario in QCI's payment risk model.
Vendor PQC Readiness Assessment#
- The governance process for evaluating third-party vendors' quantum migration plans. A supply chain risk management requirement.
Emerging Threats & Future Risks
The horizon. Some of these are speculative; some are already operational; all of them belong in a quantum risk register so they cannot be claimed as surprises later.
CRQC Arrival Date (Governance Definition)#
- The date after which organizations must assume decryption capability exists. A planning parameter for migration completion, distinct from scientific estimates.
Cryptographic Stack Modernization#
- The comprehensive upgrade of all cryptographic components to enable crypto-agility. Enables future algorithm changes without repeating full migration.
Forward Secrecy (Post-Quantum)#
- The property that compromising long-term keys does not expose past session keys. Critical for reducing HNDL exposure windows.
Harvest Now, Decrypt Later (HNDL) Risk Horizon#
- The measurable timeframe during which captured data remains vulnerable until decryption becomes possible. A function of data retention and CRQC arrival estimates.
Hybrid Key Exchange#
- Cryptographic protocol combining traditional and PQC key exchange. Reduces HNDL risk horizon by over two-thirds compared to delayed PQC adoption.
Post-Quantum Audit#
- An independent verification of cryptographic posture, migration progress, and governance controls. Board-level assurance mechanism.
Post-Quantum Cryptography Transition#
- The multi-year, organization-wide process of replacing vulnerable cryptography with PQC. A global-scale challenge requiring governance, not just technology.
PQC Workforce Gap#
- The shortage of qualified personnel capable of planning and executing cryptographic migration. 91% of businesses lack roadmaps; workforce is the binding constraint.
Quantum Computing Maturity Model#
- A governance framework assessing an organization's preparedness across people, process, and technology dimensions for quantum risk.
Quantum Governance Maturity#
- The organizational capability to oversee quantum risk through policies, standards, reporting, and continuous improvement. QCI's core value proposition.
Quantum Key Distribution (QKD)#
- A physics-based method for secure key exchange using quantum mechanics. Not a replacement for PQC in conventional computing. Not the focus of QCI-QS1.
Quantum Malware#
- Malicious software designed to target or leverage quantum computing architectures, including attacks on hybrid classical-quantum systems. An emerging threat to critical infrastructure.
Quantum Sensing Risk#
- The emerging risk that quantum sensors (gravimeters, magnetometers) could undermine physical security controls for critical infrastructure.
Quantum-native Malware#
- Malware running on quantum hardware, exploiting quantum mechanical properties. Currently theoretical but requires governance preparation.
Quantum-Safe Cryptography#
- A broader term encompassing both PQC (mathematical) and QKD (physics-based) approaches. QCI focuses on PQC as the scalable governance solution.
Regulatory Documents & Mandates
The published standards, memoranda, and reports that turn quantum risk from advisory into obligation. These are the documents auditors, regulators, and boards will cite — and the ones QCI-QS1 maps to directly.
Citi Institute Quantum Threat Report (January 2026)#
- A report published January 2026 by Citi Institute quantifying the macroeconomic impact of quantum risk, including a 19–34% probability of public-key encryption being broken by 2034 and 60–82% by 2044.
- Note 1:Key statistic: a single-day quantum attack on a top-5 bank's Fedwire access could put $2.0–$3.3 trillion GDP at risk (10–17% decline).
- Note 2:The report confirms the solution is not a "last-minute crypto patch" but a multi-year governance program — the exact problem QCI-QS1 solves.
Federal Reserve FEDS Paper 2025-093 (HNDL Risk)#
- A Finance and Economics Discussion Series working paper published September 2025 by Jillian Mascelli (Federal Reserve Board) and Megan Rodden (Federal Reserve Bank of Chicago), formally analyzing "Harvest Now, Decrypt Later" risks to distributed ledger networks.
- Note 1:Key finding: while networks can upgrade to PQC for future security, previously recorded transactions remain vulnerable, creating a "gap in data privacy protection with no complete solution."
- Note 2:Governed by QCI-QS1 data longevity classification and the Q-Risk Score's treatment of long-lived data exposure.
FN-DSA (FIPS 206 Draft)#
- Draft NIST standard for a lattice-based digital signature scheme based on FALCON, progressing through standardization as FIPS 206. Produces significantly smaller signatures than ML-DSA, ideal for certificate chains and constrained environments.
- Note 1:Smaller signature size reduces bandwidth and storage requirements for PKI infrastructure.
- Note 2:QCI-QS1 Clause 4.5 (machine identity inventory) notes FN-DSA as an emerging option for certificate authorities.
HIPAA Security Rule NPRM (January 2025)#
- The Health and Human Services Office for Civil Rights Notice of Proposed Rulemaking published January 6, 2025, to strengthen cybersecurity of Electronic Protected Health Information (ePHI), explicitly listing "Quantum Computing" as a key technology requiring risk assessment.
- Note 1:The threat of HNDL is acute for healthcare because medical records retain sensitivity for decades — longer than current CRQC arrival estimates.
- Note 2:QCI-QS1 provides the cryptographic inventory required to prove compliance with the updated HIPAA Security Rule.
IETF RFC 9794 (Hybrid Terminology)#
- Internet Engineering Task Force Request for Comments 9794, standardizing terminology for hybrid cryptographic schemes combining traditional and post-quantum algorithms in parallel.
- Note 1:The NCSC states that consistent hybrid terminology "prevents misunderstandings that can lead to security issues."
- Note 2:QCI adopts RFC 9794 terminology in QCI-QS1 to ensure audit-ready communication between technical and governance teams.
NCUA Cybersecurity Examination Priorities (2026)#
- National Credit Union Administration examination requirements prioritizing "mature, quantitative risk assessment methodology" for credit unions, with specific scrutiny on vendor incident response alignment and identity controls.
- Note 1:While not yet quantum-specific, the requirement to quantify risk in dollar terms directly supports quantum risk registers.
- Note 2:QCI's Q-Risk Score provides the quantitative framework NCUA examiners demand, translated from quantum exposure to dollar-risk language.
NIST FIPS 203 (ML-KEM)#
- The National Institute of Standards and Technology standard for Module-Lattice-Based Key-Encapsulation Mechanism, published August 13, 2024. Specifies ML-KEM-512, ML-KEM-768, and ML-KEM-1024 parameter sets. The primary standard for quantum-safe key establishment between two parties.
- Note 1:ML-KEM is derived from CRYSTALS-Kyber, selected by NIST after multiple rounds of public analysis.
- Note 2:QCI-QS1 Clause 4 (Cryptographic Inventory) requires organizations to document ML-KEM readiness status for all key-exchange protocols.
NIST FIPS 204 (ML-DSA)#
- The National Institute of Standards and Technology standard for Module-Lattice-Based Digital Signature Standard, published August 13, 2024. Specifies ML-DSA-44, ML-DSA-65, and ML-DSA-87 parameter sets. Addresses QCI's Identity Risk surface by preventing signature forgery.
- Note 1:ML-DSA is derived from CRYSTALS-Dilithium. Security relies on Module Learning With Errors (MLWE) problem.
- Note 2:QCI-QS1 Domain D6, Clause 4.5 governs machine identity inventory requirements for ML-DSA adoption.
NIST FIPS 205 (SLH-DSA)#
- The National Institute of Standards and Technology standard for Stateless Hash-Based Digital Signature Standard, published August 13, 2024. A diversification option relying solely on cryptographic hash functions for security, independent of number-theoretic assumptions.
- Note 1:SLH-DSA is derived from SPHINCS+. Produces larger signatures than ML-DSA but offers different security properties.
- Note 2:Required for high-assurance environments where lattice-based concentration risk is unacceptable per QCI-QS1 diversification guidance.
NIST HQC Selection (March 2025)#
- NIST's March 2025 selection of Hamming Quasi-Cyclic (HQC) as an additional Key Encapsulation Mechanism for standardization, based on code-based cryptography from the fourth round of the PQC standardization process.
- Note 1:HQC provides diversification away from lattice-based assumptions, addressing concentration risk in ML-KEM-only implementations.
- Note 2:QCI-QS1 diversification guidance references HQC as a future option for high-assurance environments.
NIST IR 8138 (Multi-Party Threshold Schemes)#
- NIST Interagency Report 8138 on multi-party threshold cryptography, providing foundational guidance for distributing trust across multiple entities — a key consideration for quantum-resistant key management.
- Note 1:Threshold schemes reduce the risk of single-point compromise in quantum-vulnerable key storage.
- Note 2:QCI-QS1 Clause 4.2 references NIST IR 8138 for key distribution governance.
NIST SP 1800-38B (Migration to PQC)#
- NIST Special Publication 1800-38B providing practical guidance for migrating enterprise systems to post-quantum cryptography, including cryptographic discovery, algorithm selection, and hybrid implementation.
- Note 1:Complete cryptographic discovery (CBOM) is identified as the prerequisite for any migration.
- Note 2:QCI's posture review builds the inventory NIST SP 1800-38B requires before organizations spend capital on new algorithms.
NSM-10 (National Security Memorandum on Quantum Computing)#
- A White House memorandum dated May 4, 2022, mandating U.S. federal agencies prioritize "timely and equitable transition" to post-quantum cryptography "with the goal of mitigating as much of the quantum risk as is feasible by 2035."
- Note 1:The 2035 deadline applies to federal civilian systems and serves as a de facto standard for regulated entities.
- Note 2:QCI-QS1 provides the governance roadmap to achieve NSM-10 compliance without operational disruption.
OMB PQC Migration Memorandum#
- U.S. Office of Management and Budget directive requiring federal agencies to begin structured migration to post-quantum cryptography, referenced in the Citi Institute report as a model for private sector action.
- Note 1:The memorandum establishes migration milestones and reporting requirements for civilian agencies.
- Note 2:QCI-QS1's five-phase Q-Ready Framework (Discovery, Planning, Implementation, Validation, Maintenance) maps directly to OMB requirements.
SEC PQFIF Proposal#
- The Post-Quantum Financial Infrastructure Framework submitted to the SEC Crypto Assets Task Force on September 3, 2025, proposing automated vulnerability assessment, risk-based migration planning, and hybrid cryptographic implementation for financial markets.
- Note 1:The proposal explicitly states that quantum risk "is not a far-future theoretical concern" and requires "immediate board-level attention."
- Note 2:QCI-QS1 aligns directly with PQFIF's assessment and migration methodologies.