pager or cellular phone since the owner has immediate access to the code upon transmission and longer when communications channel 84 comprises a voice mail system which the owner has to affirmatively access to receive the code if the second password was not received within the predetermined period of time analyzing means 12 denies entry to the secured domain e g computer 80 if the second password was received within the predetermined period of time analyzing means 12 compares it to the code which was previously generated if the second password is not substantially identical to the previously generated code analyzing means 12 denies individual 18 entry to the secured domain e g computer 80 if the received password is substantially identical to the code analyzing means 12 grants individual 18 entry into the secured domain as will be readily apparent to those of ordinary skill in the art timing means 40 provides yet a third level of security to computer system 80 moreover it should also be apparent to one of ordinary skill in the art that this u201c predetermined time u201d may be as short or as small as several milli seconds or micro seconds this is particularly true if in yet another embodiment of applicant 39 s invention the password generated by communication means 14 is received by a computerized device which is adapted to received the password and to generate a new password code in a substantially automatic manner referring now to fig3 there is shown a block diagram of a third embodiment of a computer security system made in accordance with the principles of the preferred embodiment of.