TryToggleAlwaysUv Method

TryToggleAlwaysUv()

Try to toggle the YubiKey's "alwaysUv" option (set to false if currently true or set to true if currently false. If the YubiKey selected does not support the "alwaysUv" option, this method will return false.

C#
public bool TryToggleAlwaysUv()

Returns

System.Boolean

A boolean, true if the YubiKey was able to toggle the "alwaysUv" and "makeCredUvNotReqd" options, false if the YubiKey does not support this feature.

Exceptions

Type Condition
Ctap2DataException

The YubiKey could not perform the operation, even though the always UV toggle feature is supported.

Remarks

See the FIDO2 standard, section 7.2, for a discussion of the always UV feature.

It is possible to toggle the feature only if the "alwaysUv" option is present on the YubiKey. If the "alwaysUv" option is not present, this method will return false.

This method will also toggle the "makeCredUvNotReqd" option as well. This option will almost certainly be the opposite of "alwaysUv".

Before calling this method, you should check the "alwaysUv" option in the AuthenticatorInfo. If it is already true and you want it true, don't call this method. 

   OptionValue optionValue = fido2Session.AuthenticatorInfo.GetOptionValue(
       AuthenticatorOptions.alwaysUv);
   if (optionValue == OptionValue.False)
   {
       _ = fido2Session.TryToggleAlwaysUv();
   }

The enable toggle always UV operation requires a PinUvAuthToken with permission "acfg" (Authenticator Configuration). If the "alwaysUv" option is present, this method will need the AuthToken. If the method needs an AuthToken, it will get one using the KeyCollector. If you do not want to use a KeyCollector, make sure you verify the PIN or UV with thee AuthenticatorConfiguration permission before calling this method.