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QTS-09.8: Algorithm Negotiation Integrity

QTS 7 — High Protect

Mechanisms exist to configure Technology Assets, Applications and/or Services (TAAS) to prevent attackers from forcing quantum-vulnerable algorithms through: (1) Integrity-protected algorithm negotiation (e.g., TLS 1.3 handshake transcript); (2) Disallowing negotiation of classical-only cipher suites once Post-Quantum Cryptography (PQC) is deployed; and (3) Monitoring for downgrade attempts.

Control Question: Does the organization configure Technology Assets, Applications and/or Services (TAAS) to prevent attackers from forcing quantum-vulnerable algorithms through: (1) Integrity-protected algorithm negotiation (e.g., TLS 1.3 handshake transcript); (2) Disallowing negotiation of classical-only cipher suites once Post-Quantum Cryptography (PQC) is deployed; and (3) Monitoring for downgrade attempts?

Capability Maturity Model

Level 0 — Not Performed

Practices are non-existent, based on the inability to demonstrate an implemented and operational capability. A reasonable person would conclude the control is not being performed.

Level 1 — Performed Informally

Quantum Security (QTS) domain capabilities are ad hoc and inconsistent. Capability criteria associated with this control may include:

Level 2 — Planned & Tracked

SCR-CMM Level 2 criteria definitions are not available for this control: ▪ A reasonable person would conclude a well-defined and standardized process is required. ▪ At this level of maturity, the “requirements-driven” nature of performing the control is focused on a localized and/or regionalized implementation, not uniform and consistent across the organization. ▪ Requirements are narrowly scoped for applicability and are primarily derived from compliance obligations (e.g., laws, regulations and contracts).

Level 3 — Well Defined

Quantum Security (QTS) capabilities are standardized across the entity for applicability to People, Processes, Technologies, Data and/or Facilities (PPTDF) to ensure consistency for Technology Assets, Applications, Services and/or Data (TAASD). Capability criteria associated with this control reasonably expect the following criteria to exist: ▪ Policies and standards associated with QTS domain capabilities are formally documented and centrally-managed by the entity's Governance, Risk & Compliance (GRC) team, or similar function. ▪ Standardized Operating Procedures (SOP) associated with QTS domain capabilities are well-documented and kept current by process owners. ▪ A risk management team, or similar function, is appropriately staffed and supported to implement and maintain QTS domain capabilities. ▪ Technology is leveraged to enhance the efficiency and accuracy of risk management operations (e.g., risk management solution, GRC platform and TPRM tool). ▪ The entity's Governance, Risk & Compliance (GRC) team, or similar function, works with business stakeholders and process owners to appropriately scope and reasonably implement cybersecurity and data protection controls associated with QTS domain capabilities to address Minimum Compliance Requirements (MCR) (e.g., applicable statutory, regulatory and/or contractual requirements) and Discretionary Security Requirements (DSR) (e.g., entity-required controls). ▪ An implemented and operational capability exists to configure Technology Assets, Applications and/or Services (TAAS) to prevent attackers from forcing quantum-vulnerable algorithms through: (1) Integrity-protected algorithm negotiation (e.g., TLS 1.3 handshake transcript); (2) Disallowing negotiation of classical-only cipher suites once Post-Quantum Cryptography (PQC) is deployed; and (3) Monitoring for downgrade attempts.

Level 4 — Quantitatively Controlled

Utilize SCR-CMM Level 3 criteria definitions: ▪ There are no defined Level 4 criteria, since it is reasonable to assume a quantitatively-controlled process is not necessary to operationalize this control. ▪ While it may be possible to develop “metrics-driven” capabilities for this control, the criteria would be organization-specific to define.

Level 5 — Continuously Improving

Utilize SCR-CMM Level 3 or Level 4 (if available) criteria definitions: ▪ There are no defined Level 5 criteria, since it is reasonable to assume a continuously-improving process is not necessary to operationalize this control. ▪ Level 5 capabilities should be considered “world-class” where the control builds on Level 4 capabilities, but are continuously improving through Artificial Intelligence (AI) and/or Machine Learning (ML) technologies. ▪ While it may be possible to develop responsive capabilities for this control through the use of AI and/or ML technologies, the criteria would be organization-specific to define.

Assessment Objectives

  1. QTS-09.8_A01 Technology Assets, Applications and/or Services (TAAS) are configured to prevent attackers from forcing quantum-vulnerable algorithms.
  2. QTS-09.8_A02 integrity-protected algorithm negotiation is used (e.g., TLS 1.3 handshake transcript).
  3. QTS-09.8_A03 negotiation of classical-only cipher suites is disallowed once Post-Quantum Cryptography (PQC) is deployed.
  4. QTS-09.8_A04 downgrade attempts are monitored.

Technology Recommendations

Micro/Small

  • Enforce TLS 1.3 (includes transcript integrity protection)
  • Disable TLS 1.0/1.1 and weak cipher suites

Small

  • TLS 1.3 enforcement
  • Disable deprecated cipher suites
  • Monitor for TLS downgrade attempts via web application firewall

Medium

  • TLS 1.3 with strong cipher suite enforcement
  • Monitoring for algorithm downgrade attempts
  • Disallow classical-only cipher suite negotiation where PQC is deployed

Large

  • TLS 1.3 enforcement with integrity-protected handshake
  • Algorithm downgrade monitoring and alerting
  • Cipher suite allowlisting across enterprise TLS infrastructure

Enterprise

  • Enterprise TLS cipher suite governance with automated enforcement
  • Algorithm negotiation integrity monitoring at scale
  • Automated detection of downgrade attempts
  • Integration with network security monitoring and SIEM

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