U2F doesn't protect you from an untrusted machine, it protects you from untrusted websites. https://security.stackexchange.com/questions/157756/mitm-attacks-on

U2F doesn't protect you from an untrusted machine, it protects you from untrusted websites. https://security.stackexchange.com/questions/157756/mitm-attacks-on-fido-uaf-and-u2f https://security.stackexchange.com/questions/157756/mitm-att... The security model relies on the browser validating the origin.