Windows 11 must be configured to prioritize ECC Curves with longer key lengths first.

Documentable No

Rule ID SV-253363r971535_rule

CCI References

CCI-000803

Discussion

Use of weak or untested encryption algorithms undermines the purposes of utilizing encryption to protect data. By default Windows uses ECC curves with shorter key lengths first. Requiring ECC curves with longer key lengths to be prioritized first helps ensure more secure algorithms are used.

Check Procedure

If the following registry value does not exist or is not configured as specified, this is a finding:

Registry Hive: HKEY_LOCAL_MACHINE
Registry Path: \SOFTWARE\Policies\Microsoft\Cryptography\Configuration\SSL\00010002\

Value Name: EccCurves

Value Type: REG_MULTI_SZ
Value: NistP384 NistP256

Fix Action

Configure the policy value for Computer Configuration >> Administrative Templates >> Network >> SSL Configuration Settings >> "ECC Curve Order" to "Enabled" with "ECC Curve Order:" including the following in the order listed:

NistP384
NistP256