An apparatus, system, and method for constructing, transmitting, and authenticating a password utilized by an authentication device to authenticate an access device. The authentication device receives the password from the access device, authenticates the access device if the password matches stored information, and returns an acknowledgment message that includes an index value associated with a stored character set. The access device constructs and transmits the password. The access device receives from a user, a plurality of predefined characters forming a User ID. The access device also receives the acknowledgment message and index value from the authentication device. The index value is used to identify a character set from a plurality of character sets stored in a lookup table. The access device integrates the User ID and the identified character set to generate a password, and transmits the password to the authentication device.