Various classified papers were written at GCHQ during the 1960s and 1970s which eventually led to schemes essentially identical to RSA encryption and to Diffie–Hellman key exchange in 1973 and 1974.
V 60. a 70. letech vzniklo v GCHQ několik tajných dokumentů, které popisovaly schémata v podstatě identická s šifrou RSA a metodou výměny klíče Diffie-Hellman v letech 1973 a 1974.