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Cryptographic Module Validation Program CMVP

Entropy Validation Announcements

As of August 10, 2021, the entropy caveats can be applied to a FIPS 140-2 entropy assessment report submission. The following email sent to the labs provides the full information about the caveats. The SP 800-90B SHALL Statement spreadsheet discusses which requirements are allowed for a caveat. 

Dear CST Labs,

In response to feedback from the recent Entropy Source Validation Workshop, as well as specific requests to move the deadline for mandatory compliance to NIST SP 800-90B, the CMVP has decided to allow provisional validation of FIPS 140-2 modules with entropy sources that do not meet all the requirements of NIST SP 800-90B.  Instead, they will only need to meet a subset of the requirements in SP 800-90B.  We will publish a table of all the requirements (i.e., all SHALL statements) extracted from SP 800-90B and indicate which of these are still required and which are optional.

Conditions on these provisional validations are as follows:

  • They are only available for entropy sources in a FIPS 140-2 module.
  • The module’s validation certificate will be marked with a caveat: “CAVEAT: The module’s entropy source does not meet all the requirements of NIST SP 800-90B.”
  • The entropy source is bound to the FIPS 140-2 module validation and not eligible for the following:
    • Conversion to a stand-alone entropy source validation (when this becomes available for SP 800-90B-compliant entropy sources at a future date TBD).
    • Use in a compliant SP 800-90C RBG construction (SP 800-90C is still in draft).
  • They are listed on the module’s validation certificate as a non-approved but allowed “NDRNG”.

The first draft of the SP 800-90B requirements table will be published next week for feedback and comment.

Please be advised that though we will validate FIPS 140-2 modules with entropy sources that meet these provisional requirements, the CMVP continues to strongly recommend full compliance with SP 800-90B.

Best regards,

The CAVP and CMVP Teams

All FIPS 140-2 and FIPS 140-3 submissions are required to provide justification of conformance to SP 800-90B if applicable.


Created October 11, 2016, Updated September 09, 2021