Method and apparatus for transmitting credentials to a transaction processing system, the credentials arranged in sets and a set including a unique identifier and verification data elements. Credentials are activated and are then available for use in at least one subsequent transaction. In the transaction, in response to receiving authorization from a user, the unique identifier and verification data elements from a set are transmitted to the transaction processing system for the user. The credentials are activated using an activation mode selected from at least a first activation mode and a second activation mode. In the first activation mode, additional user input for the verification data elements associated with the unique identifier is received from the user. In the second activation mode, the user is authenticated, and verification data elements are received via a data communications network are received from a trusted data processing system remote from the user.