# NIST SP 800-53 Rev. 5 AC-17(2) — Protection Of Confidentiality And Integrity Using Encryption - Source: https://support.icompaas.com/compliance/nist-sp-800-53-rev-5/ac-17-2-protection-of-confidentiality-and-integrity-using-encryption - Section: [Compliance](https://support.icompaas.com/compliance) › [NIST SP 800-53 Rev. 5 Controls](https://support.icompaas.com/compliance/nist-sp-800-53-rev-5) › AC — Access Control - Last updated: 2026-06-05 - Publisher: iCompaas, Inc. (https://www.icompaas.com) **NIST SP 800-53 Rev. 5**·Control `AC-17(2)`·critical·Component: **Access Control** ## What this control requires > Implements cryptographic mechanisms like VPNs or TLS to protect confidentiality and integrity of remote access sessions, ensuring secure end-to-end communication over external networks. This control supports the Transport Layer Security (TLS) Protocol capability within the Access Control family. > > — NIST SP 800-53 Rev. 5, Control AC-17(2) ### In plain English Implements cryptographic mechanisms like VPNs or TLS to protect confidentiality and integrity of remote access sessions, ensuring secure end-to-end communication over external networks. In practice, this means you can prove you access management-level controls on a defined cadence. ## Why it matters SP 800-53 is the catalogue every U.S. federal authorisation (FedRAMP, FISMA, CMMC) and most regulated industries point at. A missing control surfaces as a Plan of Action & Milestones (POA&M) item that an Authorizing Official must approve before the Authority To Operate is granted or renewed. This control is rated **critical** in the source catalogue. Treat gaps here as production incidents in the risk register, not housekeeping. ## What an auditor looks for A 3PAO (FedRAMP) or Independent Assessor (NIST RMF) tests against NIST SP 800-53A assessment procedures. For each control they expect a documented implementation that addresses every assessment objective (Examine, Interview, Test) and an implementation summary in the System Security Plan. Within **Access Control**, the assessor will trace your implementation back to the catalogue reference (Control AC-17(2)) and look for objective evidence on the latest two assessment cycles. ## How to implement 1. Write a short policy stating intent, scope and named owner. 2. Encode it as a platform guardrail — SCP, Azure Policy initiative, Organisation Policy, or repository policy. 3. Wire a monitoring signal that catches drift (CSPM rule, SIEM rule, scheduled query, Workspace alert) and ticket it. 4. Review on a documented cadence and capture the review in the risk register or compliance tracker. ### Operational checklist - **Access.** Document the trigger, the owner and the cadence. - **Security.** Document the trigger, the owner and the cadence. - **Network.** Document the trigger, the owner and the cadence. - **Review.** Document the trigger, the owner and the cadence. - **Remote.** Document the trigger, the owner and the cadence. - **Scope:** management, access control, encryption, protection, identity, review, capability, networks. ## Evidence to collect - **Identity Scan.** IAM / IdP exports — Entra ID, Okta, IAM Identity Center, Workspace directory — showing accounts, roles, MFA state and last sign-in. Identity analytics (Okta, SailPoint, Access Analyzer) demonstrates least-privilege. Focus: Protection Of Confidentiality And Integrity Using Encryption. ## How it maps to other frameworks Computed from shared tags, control component and key-operation subjects — handy when you are reconciling controls across an audit. - [**NIST SP 800-171 Rev. 3 3.8.5** — Media Transport](https://support.icompaas.com/compliance/nist-sp-800-171-rev-3/3-8-5-media-transport) - [**CIS Controls v8 6.7** — Centralize Access Control](https://support.icompaas.com/compliance/cis-controls-v8/6-7-centralize-access-control) - [**ISO/IEC 27001:2022 A.7.2** — Physical entry](https://support.icompaas.com/compliance/iso-27001-2022/a-7-2-physical-entry) - [**BSI C5:2020 PS-04** — Physical site access control](https://support.icompaas.com/compliance/bsi-c5-2020/ps-04-physical-site-access-control) - [**SOC 2 (2017 TSC) CC6.4** — Physical Access Controls](https://support.icompaas.com/compliance/soc-2-trust-services-criteria/cc6-4-physical-access-controls) ## Related controls in NIST SP 800-53 Rev. 5 - [**Control MP-5** — Media Transport](https://support.icompaas.com/compliance/nist-sp-800-53-rev-5/mp-5-media-transport) - [**Control AC-18(1)** — Authentication And Encryption](https://support.icompaas.com/compliance/nist-sp-800-53-rev-5/ac-18-1-authentication-and-encryption) - [**Control MP-5(4)** — Cryptographic Protection](https://support.icompaas.com/compliance/nist-sp-800-53-rev-5/mp-5-4-cryptographic-protection) - [**Control AC-4(22)** — Access Only](https://support.icompaas.com/compliance/nist-sp-800-53-rev-5/ac-4-22-access-only) - [**Control AC-18** — Wireless Access](https://support.icompaas.com/compliance/nist-sp-800-53-rev-5/ac-18-wireless-access) - [**Control AC-24(1)** — Transmit Access Authorization Information](https://support.icompaas.com/compliance/nist-sp-800-53-rev-5/ac-24-1-transmit-access-authorization-information) ## References - [NIST Computer Security Resource Center — NIST SP 800-53 Rev. 5](https://csrc.nist.gov/Projects/risk-management/sp800-53-controls) - Catalogue identifier: `Control AC-17(2)` Topics: identity accessnetwork securityencryption in transitidentity managementaccess reviewprivileged access ## Related compliance guidance - [NIST SP 800-53 Rev. 5: a practical implementation guide for cloud teams](https://support.icompaas.com/compliance/nist-sp-800-53-rev-5): Start with the full NIST SP 800-53 implementation guide — scope, roadmap, evidence and how the assessment runs. - [NIST SP 800-171 and CMMC: a practical guide to protecting CUI in the cloud](https://support.icompaas.com/compliance/nist-sp-800-171-rev-3): If your obligation is protecting CUI in your own systems for a federal or defence contract, this derived subset — not the full catalogue — is the requirement. - [SOC 2 compliance: a practical implementation guide for cloud-native SaaS teams](https://support.icompaas.com/compliance/soc-2-trust-services-criteria): Most commercial SaaS already hold a SOC 2 Type 2, and FedRAMP 20x Class A is designed for providers that have one.