A request is received from a computing device for substitute data, with access to the substitute data being contingent upon successful multi-factor authentication of the first service. Signature data based on the request is generated using a first key of public-private key pair. Credential proof and the signature is provided to a second service, which verifies the credential proof as a first factor of the multi-factor authentication and verifies, using a second key, the signature as a second factor of the multi-factor authentication. The substitute data is obtained as a result of authentication by the second service. The computing device is caused, by providing the substitute data to the computing device, to input the substitute data into the interface in place of data associated with the first entity.