NixOS must implement NIST FIPS-validated cryptography for the following: to provision digital signatures, to generate cryptographic hashes, and to protect unclassified information requiring confidentiality and cryptographic protection in accordance with applicable federal laws, Executive Orders, directives, policies, regulations, and standards.

Use of weak or untested encryption algorithms undermines the purposes of using encryption to protect data. The operating system must implement cryptographic modules adhering to the higher standards approved by the federal government since this provides assurance they have been tested and validated.

Satisfies: SRG-OS-000478-GPOS-00223, SRG-OS-000396-GPOS-00176

Verify NixOS is configured to operate in FIPS mode with the following command:

$ grep fips /proc/cmdline

BOOT_IMAGE=(hd0,msdos1)/nix/store/glc0midc78caq9sc7pzciymx4c3in7kn-linux-6.1.64/bzImage init=/nix/store/grl4baymr9q60mbcz3sidm4agckn3bx5-nixos-system-nixos-23.1.1.20231129.057f9ae/init audit=1 audit_backlog_limit=8192 fips=1 loglevel=4

If the "fips" entry does not equal "1" or is missing, this is a finding.

Configure NixOS to run in FIPS mode.

Add the following Nix code to the NixOS Configuration, usually located in /etc/nixos/configuration.nix or /etc/nixos/flake.nix:

boot.kernelParams = [ "fips=1" ];

Rebuild and switch to the new NixOS configuration: $ sudo nixos-rebuild switch

A reboot is required for the changes to take effect.