FAQ — Qontomcrypt | Post-Quantum Cryptography Questions Answered

Question 1

What is post-quantum cryptography (PQC)?

Accepted Answer

Post-quantum cryptography (PQC) refers to cryptographic algorithms designed to be secure against attacks from both classical computers and quantum computers. Today's widely used public-key algorithms — RSA, ECC, and Diffie-Hellman — rely on mathematical problems (integer factorisation and discrete logarithm) that a sufficiently powerful quantum computer could solve efficiently using Shor's algorithm. PQC algorithms are built on different mathematical foundations — such as lattice problems, hash functions, and code-based problems — that are believed to resist quantum attacks. NIST finalised the first PQC standards in 2024: FIPS 203 (ML-KEM), FIPS 204 (ML-DSA), and FIPS 205 (SLH-DSA).

Question 2

Why does quantum computing threaten current encryption?

Accepted Answer

Most of today's public-key cryptography — used to secure TLS connections, digital signatures, key exchange, and PKI — relies on the computational difficulty of factoring large numbers or solving discrete logarithm problems. A cryptographically relevant quantum computer (CRQC) running Shor's algorithm could break RSA-2048 and ECC-256 in hours or days, compared to the billions of years it would take a classical computer. Symmetric encryption (AES) is less affected — Grover's algorithm halves the effective key length, so AES-256 remains secure at an effective 128-bit level. The threat is not theoretical: the question is when a CRQC will exist, not whether one will.

Question 3

When will quantum computers be able to break current encryption?

Accepted Answer

Estimates vary, but the consensus among cryptographers and national security agencies is that a cryptographically relevant quantum computer (CRQC) capable of breaking RSA-2048 could exist within 10–15 years — potentially by 2036–2041. Some threat models place the risk earlier. The uncertainty itself is the problem: organisations with long-lived sensitive data cannot wait for certainty before acting, because the harvest-now-decrypt-later attack means adversaries are collecting encrypted data today to decrypt later. Migration timelines of 10–20 years mean organisations need to start now.

Question 4

What NIST standards should we be implementing?

Accepted Answer

NIST finalised three PQC standards in August 2024. FIPS 203 (ML-KEM, based on CRYSTALS-Kyber) is the primary standard for key encapsulation — used to establish shared secrets over untrusted channels. FIPS 204 (ML-DSA, based on CRYSTALS-Dilithium) is the primary standard for digital signatures. FIPS 205 (SLH-DSA, based on SPHINCS+) is a stateless hash-based signature scheme providing a backup option with different security assumptions. NIST also published FIPS 206 (FN-DSA, based on FALCON) for applications requiring compact signatures. Qontomcrypt's Data Protection Platform uses ML-KEM-768 (FIPS 203) for key encapsulation, combined with X25519 in a hybrid construction.

Question 5

What is the harvest-now, decrypt-later (HNDL) attack?

Accepted Answer

Harvest-now, decrypt-later (HNDL) is a threat model in which an adversary intercepts and stores encrypted data today — before a quantum computer exists — with the intention of decrypting it once a cryptographically relevant quantum computer becomes available. The attack is passive and undetectable: the adversary simply records encrypted traffic or exfiltrates encrypted archives. Any data encrypted today with RSA or ECC that must remain confidential for more than 10–15 years is already at risk. This includes medical records, financial contracts, legal documents, intellectual property, and classified government communications.

Question 6

Which types of data are most at risk from HNDL?

Accepted Answer

Data is most at risk when it has a long confidentiality requirement and is accessible to an adversary today. The highest-risk categories include: long-term financial records and contracts (30+ year retention); medical and health records (lifetime retention obligations); legal and regulatory documents; intellectual property and trade secrets; government and national security communications; and personal identity data subject to long-term regulatory obligations. Data with a short shelf life — session tokens, ephemeral communications — is less exposed because it will have no value by the time a CRQC exists.

Question 7

How do I know if my organisation is already being targeted?

Accepted Answer

HNDL attacks are passive and leave no detectable trace — the adversary records encrypted traffic without interacting with your systems. You cannot detect whether your data has already been harvested. Nation-state actors and well-resourced threat groups are known to be conducting HNDL operations against high-value targets including financial institutions, healthcare organisations, government agencies, and critical infrastructure operators. The absence of a detected breach does not mean your data is safe. The only effective response is to migrate to quantum-safe cryptography before a CRQC exists.

Question 8

What is a Cryptographic Bill of Materials (CBOM)?

Accepted Answer

A Cryptographic Bill of Materials (CBOM) is a complete, structured inventory of every cryptographic asset in your organisation — algorithms, keys, certificates, protocols, libraries, and the systems that depend on them. It is the foundation of any PQC migration programme. Without a CBOM, you cannot know what needs to be migrated, in what order, or what the dependencies are. Qontomcrypt builds your CBOM through a combination of automated scanning, passive observation, configuration review, and stakeholder interviews. The CBOM is a living document — it must be maintained and updated as your cryptographic estate evolves.

Question 9

What does a PQC Discovery Briefing involve?

Accepted Answer

A PQC Discovery Briefing is a structured 90-minute session with Qontomcrypt's advisory team. We review your organisation's current cryptographic posture, identify the highest-risk assets based on your data classification and retention requirements, and provide an initial assessment of your quantum readiness. The briefing covers the harvest-now-decrypt-later threat as it applies to your specific context, an overview of the NIST PQC standards relevant to your use cases, and a recommended path forward. The briefing is the starting point for a full PQC Discovery & CBOM engagement.

Question 10

How long does a full PQC migration take?

Accepted Answer

The average cryptographic migration takes 10–20 years for large organisations with complex, legacy-heavy estates. This is why starting now is critical — quantum-capable hardware is projected to arrive within 10–15 years. The timeline depends on the size and complexity of your cryptographic estate, the number of legacy systems with embedded cryptography, vendor readiness for PQC-capable updates, regulatory and compliance requirements, and available internal migration capacity. Qontomcrypt's wave-based migration methodology prioritises the highest-risk assets (P1 tier) for immediate action, allowing organisations to reduce their most critical exposure while planning longer-term migration waves.

Question 11

Do you work with organisations outside India?

Accepted Answer

Qontomcrypt is developed by DKUSH Innovatech, headquartered in Mumbai, India. Our advisory services are available to organisations globally. Our regulatory alignment mapping covers Indian frameworks (DPDP Act 2023, RBI IT Framework, SEBI Cybersecurity Framework, CERT-In guidelines) as well as international frameworks including NIST, ISO 27001, and sector-specific requirements. We work with financial institutions, government agencies, healthcare organisations, and critical infrastructure operators across multiple jurisdictions. Contact us to discuss your specific regulatory context.

Question 12

What is a hybrid cryptographic construction and why use one?

Accepted Answer

A hybrid cryptographic construction combines a classical algorithm with a post-quantum algorithm so that security is maintained even if one of the two is later found to be weak. For example, Qontomcrypt's Data Protection Platform uses ML-KEM-768 combined with X25519 (classical ECDH) for key encapsulation. If ML-KEM-768 were found to have an unexpected vulnerability, the X25519 component still provides classical security. If X25519 is broken by a quantum computer, ML-KEM-768 provides quantum-safe security. Hybrid constructions are recommended by NIST and major security agencies as the appropriate approach during the transition period, before PQC algorithms have accumulated the same level of cryptanalytic scrutiny as classical algorithms.

Question 13

Is AES-256 quantum-safe?

Accepted Answer

AES-256 is considered quantum-resistant, not quantum-safe in the same sense as PQC key encapsulation algorithms. Grover's algorithm provides a quadratic speedup for searching symmetric key spaces, effectively halving the security level — so AES-256 provides approximately 128 bits of security against a quantum adversary, and AES-128 provides approximately 64 bits (which is considered insufficient). AES-256 with 128-bit post-quantum security is considered adequate for most use cases. The primary quantum threat is to public-key cryptography (RSA, ECC, DH) — symmetric encryption requires key length doubling as a precaution, which AES-256 already satisfies.

Question 14

What is the Priority Score and how is it calculated?

Accepted Answer

The Priority Score is a weighted score from 0–100 that Qontomcrypt assigns to every cryptographic asset in your CBOM. It is calculated from five factors: Data Shelf Life Score (how long the protected data must remain confidential), Algorithm Exposure Score (how vulnerable the algorithm is to quantum attack), Capturability Score (how accessible the encrypted data is to an adversary today), Business Criticality Score (the business impact of a breach), and Migration Difficulty Score (the complexity of migrating this asset). Each factor is scored 1–5. The weighted combination produces the Priority Score, which determines the migration tier (P1–P4) and therefore the wave of the migration programme the asset falls into.

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