Secured computer system

A multi-computer system comprising at least two interacting computers interconnected by two physically separated unidirectional interfaces, one of said two unidirectional interfaces being configured to provide a direct dataflow exclusively from a first of said two interacting computers to a second of said two interacting computers, and the other of said two unidirectional interfaces being configured to provide a counter dataflow exclusively from the second of said two interacting computers to the first of said two interacting computers, such that in each of said at least two interconnected computers of said multi-computer system the direct and counter dataflows are unconditionally physically separated,

• wherein the first of said at least two interacting computers is a main computer, the second of said at least two interacting computers being a web-connected computer, further comprising a knowledge base computer,
• wherein neither said main computer, nor said lock computer, nor said knowledge base computer can be directly connected to the world wide web, each of said web-connected computer and said main computer being configured such that neither can directly exchange with data with the other, and
• wherein each of said web-connected computer, said main computer, and said knowledge base computer is configured to interact only through said the intermediate lock-computer,
• wherein said lock-computer comprises:
• a core computer having built-in unchangeable and immutable system software that is not modifiable by any downloaded program and is configured to be updated only by replacement of a tangible hardware component on which the system software is stored;
• the output transducer of said unidirectional interface providing unidirectional data flow from said lock-computer to said main computer and comprising an electronic display configured to display a two-dimensional image as an output interface from said unidirectional interface,
• the input transducer of said unidirectional interface providing unidirectional data flow from said main computer to said lock-computer, said unidirectional interface including a first electrical-to-optical transducer and a second optical-to-electrical transducer, wherein the outlet of said main computer includes the first transducer, and the inlet on said lock-computer includes the second transducer,
• said unidirectional interface providing a unidirectional data flow from said web-connected computer to said lock-computer and vice versa.

A multi-computer system comprising at least two interacting computers interconnected by two physically separated unidirectional interfaces, one of said two unidirectional interfaces being configured to provide a direct dataflow exclusively from a first of said two interacting computers to a second of said two interacting computers, and the other of said two unidirectional interfaces being configured to provide a counter dataflow exclusively from the second of said two interacting computers to the first of said two interacting computers, such that in each of said at least two interconnected computers of said multi-computer system the direct and counter dataflows are unconditionally physically separated,

• the multi-computer system further comprising an intermediate lock-computer, wherein any pair of computers of said multi-computer system except said lock-computer is configured to interact only through said intermediate lock-computer,
• said lock-computer being configured to, after an end of a session, said lock-computer is temporarily locked from all external connections including connections with said main computer, with said knowledge base and with said web-connected computer,
• wherein all data having been temporarily stored in a rewritable memory of said lock-computer are completely erased, and said rewritable memory of said lock-computer is configured to be self-reformatted responsive to being completely erased.

A multi-computer system comprising at least two interacting computers interconnected by two physically separated unidirectional interfaces, one of said two unidirectional interfaces being configured to provide a direct dataflow exclusively from a first of said two interacting computers to a second of said two interacting computers, and the other of said two unidirectional interfaces being configured to provide a counter dataflow exclusively from the second of said two interacting computers to the first of said two interacting computers, such that in each of said at least two interconnected computers of said multi-computer system the direct and counter dataflows are unconditionally physically separated,

• wherein at least one of said two unidirectional interfaces is an electronic display configured to display a two-dimensional image as an output interface of the one of the interacting computers providing the data input,
• wherein at least the other of said two unidirectional interfaces includes a matrix of photo receivers as an input interface of the other of said interacting computers, and
• wherein a ratio between a resolution of said electronic display, H(1)×V(1), and resolution of said matrix of photo receivers, H(2)×V(2), satisfies the condition:
• H(2)>H(1), V(2)>V(1), where H(1) is a first number of horizontal pixels, H(2) is a second number of horizontal pixels, V(1) is a first number of vertical pixels, and V(2) is a second number of vertical pixels.

A multi-computer system comprising at least two interacting computers interconnected by two physically separated unidirectional interfaces, one of said two unidirectional interfaces being configured to provide a direct dataflow exclusively from a first of said two interacting computers to a second of said two interacting computers, and the other of said two unidirectional interfaces being configured to provide a counter dataflow exclusively from the second of said two interacting computers to the first of said two interacting computers, such that in each of said at least two interconnected computers of said multi-computer system the direct and counter dataflows are unconditionally physically separated,

• wherein at least one of said two unidirectional interfaces is an electronic display configured to display a two-dimensional image as an output interface of the one of the interacting computers providing the data input, and
• wherein at least the other of said two unidirectional interfaces includes a matrix of photo receivers as an input interface of the other of said interacting computers,
• the multi-computer system further comprising an electrical-to-optical transducer operatively coupled to the electronic display and being configured to automatically convert between a red-green-blue (RGB) mode and a non-RGB mode including a cyan-magneta-yellow-black (CMYK) mode, an index mode, a grayscale mode, or a bitmap mode for detection by said matrix of photo receivers and conversion by an optical-to-electrical transducer into the data input.