Secure comm program, Sockets + LINK

[jpp at markv.com]

	  Andrew			  Betty

    KCA=Initial key K0 in s/w       KCB=Initial key K0 in s/w
    KCB=Initial key K0 in s/w       KCA=Initial key K0 in s/w
    KCi= KCA + KCB                  KCi= KCA + KCB
    KCo= KCA + KCB                  KCo= KCA + KCB

    Use KCi for reading, and	    Use KCi for reading, and
    KCo for writeing to the         KCo for writeing to the
    chanell for a while             chanell for a while

    Requset a new sesion key        Requset a new sesion key
    DES(KCo,RSA(BP,K1A))            KRB=DES(KCo,RSA(AP,K1B))
            \_____________   ______________/
      KCi=KCA+KCB         \ /         KCi=KCB+KCA
      KCo=K1A+KCB          X	      KCo=K1B+KCA
             _____________/ \______________
            /                              \
    Sevice new key request
    TA=DES(KCi,KRB)
    K1B=RSA(AS,TA)
    KCi=K1A+K1B