Artifact FAQGLOBALFIPS 197 AES

FIPS 197 AES What it proves, and what it does not prove

FIPS 197 specifies AES, including AES-128, AES-192, and AES-256. It does not by itself prove that a product, service, or cryptographic module is FIPS 140-3 validated.

Use this FAQ to separate the AES algorithm standard from CAVP algorithm testing and CMVP module validation evidence.

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Author
Sorena AI
Published
May 9, 2026
Updated
May 9, 2026
Questions
2

Structured answer sets in this page tree.

Primary sources
4

Cited legal and guidance references.

Publication metadata
Sorena AI
Published May 9, 2026
Updated May 9, 2026
Overview

Short answer: FIPS 197 is the AES algorithm standard. It supports a claim that AES is a FIPS-approved symmetric block cipher when used with an approved or NIST-recommended mode, but teams still need separate evidence for the implementation tested by CAVP and for any FIPS 140-3 cryptographic module validation claimed through CMVP.

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2 of 2 questions
Question 1

What does FIPS 197 actually define?

FIPS 197 defines the Advanced Encryption Standard as a symmetric block cipher for protecting electronic data. The standard specifies three AES variants: AES-128, AES-192, and AES-256.

Each AES variant uses 128-bit data blocks. The suffix names the key length: 128, 192, or 256 bits. The 2023 update kept the algorithm intact while updating the publication, diagrams, terms, and editorial material.

  • Use FIPS 197 to identify the AES algorithm family and the allowed AES key sizes.
  • Record the AES mode separately because FIPS 197 says AES shall be used with a FIPS-approved or NIST-recommended mode of operation.
  • Do not describe Rijndael options outside AES-128, AES-192, or AES-256 as FIPS 197 AES.
Citations
Question 2

Does using AES mean a module is FIPS validated?

No. FIPS 197 defines the AES algorithm; it is not a cryptographic module certificate. A product can use AES while still needing separate evidence about the implemented algorithm, module boundary, operational environment, approved services, and FIPS 140-3 validation status.

For algorithm evidence, check the CAVP record for the tested AES implementation and parameters. For module evidence, check the CMVP record and security policy for the validated module, certificate status, approved mode, services, and caveats.

  • Treat an AES library name, marketing claim, or source-code reference as insufficient by itself.
  • Confirm the tested AES implementation, mode, key sizes, certificate identifier, vendor, version, and operational environment in the applicable CAVP or CMVP record.
  • When the claim is about FIPS 140-3, tie the AES evidence to the validated cryptographic module boundary rather than to the surrounding application alone.
Citations
Recommended next step

Review FIPS 197 AES claims before they reach customers or audits

Use this FAQ to narrow broad AES wording into source-linked statements about the algorithm, implementation testing, and module validation evidence you actually have.

Assessment workflow
Check AES evidence

Map AES claims to the FIPS 197 source, CAVP records, CMVP records, and deployment configuration evidence.

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Research workflow
Research a validation question

Use cited research support when an AES, CAVP, or CMVP claim needs source-linked review.

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Talk to Sorena
Talk through FIPS evidence

Review AES wording, certificate references, approved-mode assumptions, and customer-facing validation claims with Sorena.

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Primary sources

References and citations

CMVP Implementation Guidance for FIPS 140-3
csrc.nist.gov
Referenced sections
  • Explains that CMVP validates cryptographic modules and CAVP addresses testing of approved security functions referenced by FIPS 140-3.
"CAVP addresses the testing"
NIST CAVP validation search
csrc.nist.gov
Referenced sections
  • Public NIST search page for locating algorithm validation records such as AES implementation certificates.
"validation search"
NIST FIPS 197-upd1 Advanced Encryption Standard
doi.org
Referenced sections
  • Defines AES as the FIPS-approved algorithm and specifies AES-128, AES-192, AES-256, 128-bit blocks, and approved or recommended mode usage.
"Advanced Encryption Standard (AES)"
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