Abstract: A method of proximity access control comprising: defining a master proximity key exhibiting a particular visual encoding; defining at least one additional proximity key exhibiting a particular visual encoding different than the particular visual encoding exhibited by the master proximity key; detecting the master proximity key; detecting one of the at least one additional proximity key contemporaneously with the detected master proximity key; and enabling the detected additional proximity key, the enabling being associated with the particular visual encoding. An identifier of the visual encoding is preferably stored on each proximity key. Preferably, the visual encoding is constituted of color coding, and only a single proximity key of each color is thus authorized.