User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_4) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/66.0.3359.139 Safari/537.36 Steps to reproduce: This bug can be reproduced on the yubico demo site: https://demo.yubico.com/u2f I am attempting to authenticate using a FIDO U2F security key. I have one key registered that is a Yubikey U2F device (let's refer to it as Key A), and attempting to authenticate with a Yubikey 4 device (let's refer to this as Key B). The registeredKeys array sent contains one key (Key A) but Key B is inserted. The keyHandle does not match the inserted device (this is expected and intentional). Actual results: I receive error code 1 OTHER_ERROR Expected results: I should receive error code 4 DEVICE_INELIGIBLE (as received by Chrome 66.0.3359.139) According to FIDO U2F specs (https://fidoalliance.org/specs/u2f-specs-master/fido-u2f-javascript-api.html) DEVICE_INELIGIBLE: "for a sign request it may mean the token does not know the presented key handle"