A security system for controlling access to property having a user-operated keyboard to key in and reset a composite password code. An indicator visually displays at least one code symbol varying with time. A memory device stores a current composite password code including at least two code symbols so that upon entry of the keyed-in password code through the keyboard, one of the stored password code symbols is replaced directly by the time varying code symbol to form a regenerated, composite password code which is then compared with the keyed-in password code to grant access to the property when coincidence occurs between the keyed-in and the regenerated password codes. In response to non-coincidence, an alerting signal is generated to indicate the incorrect password condition.
CROSS-REFERENCE OF RELATED APPLICATIONS
This is a continuation-in-part of U.S. patent application Ser. No. 053,731, filed on May 26, 1987, now U.S. Pat. No. 4,812,841.
A transmission and reception system including a transmitter for transmitting a signal including identification (security) information and function information, and a receiver for receiving and decoding the signal and for executing the operation defined by the function information upon verification of the identification information. The transmitter divides one or more of the identification information and the function information into two or more bit groups, and transmits these bit groups such that identification information bit groups are separated by function information and function information bit groups are separated by identification information. In one embodiment, the intermixed function and identification bit groups are transmitted without a time gap, and in another embodiment the function bit groups and the identification bit groups are arranged in groups containing one or more function information bit groups and one or more identification information bit groups, these groups then being transmitted with a time gap therebetween. The receiver includes information necessary for recombining the identification information and the function information for performing verification of the identification information and execution of the operation defined by the function information. In a further embodiment the identification information includes both fixed and variable codes, the variable code being changed after each transmission.
A method and system are provided for controlling access to a data processing system through the use of a variable password. In one embodiment, the invention substitutes the value of a variable into an expression contained in a predefined password, evaluates the expression and password, and compares the result of the valuation of the password to a character string input to the data processing system, granting access if they are identical. A range of values of certain characters of the password may be permitted. The password may require that certain characters be entered within a defined time interval measured from the entry of other characters. The values of environment variables, which are referenced by the variable password, may change from time to time, as a function, for example, of the current time or temperature or system utilization.
A computer has a floppy disk drive provided in one of the spaces for receiving disk drives of the computer, a computer keyboard and a main system board. An access control device includes a casing placed into another one of the spaces for receiving disk drives of the computer, a keypad provided on a front panel of the casing and operated so as to provide an input password, and a control unit provided within the casing and electrically connected to the keypad. The control unit includes a memory unit which contains a desired password, a microprocessor unit which receives the input password from the keypad and which generates an activating signal when the input password tallies with the desired password in the memory unit, and at least one control circuit connected to a respective one of the computer keyboard, the floppy disk drive and the main system board. Each of the control circuits is actuated by the activating signal from the microprocessor unit so as to unlock and enable the respective one of the computer keyboard, the floppy disk drive and the main system board and permit normal operation of the computer.
A computer system is provided which is compatible with existing programmable option select systems and which provides optional enhanced system setup capabilities. The enhanced system permits use of application software designed specifically for existing programmable option select systems which utilize limited system configuration data registers but further provides an optional mode accessed during system setup procedures wherein application software can access and utilize an expanded set of system setup configuration registers to enhance the performance of the computer system.
A computer system and method in which an electrically controlled "hoodlock," which prevents the computer's chassis from unauthorized opening, can be remotely accessed through powerline communications.
