A method for communication, comprising: receiving in a secure installation via a network from a remote user terminal an input comprising a stream of symbols that has been encrypted using a preselected encryption key; decoding the encrypted stream of symbols in the secure installation using a decryption key corresponding to the preselected encryption key, to produce a clear stream of symbols; using a computer program running on a processor in the secure installation, processing the symbols in the clear stream and generating a graphical output in a predefined display format in response to processing the symbols; and outputting the graphical output from the secure installation to the network, characterized in that: the stream of symbols from the remote user terminal exits an encryption circuit of an input device of the the remote user terminal through a one-way link within the input device that is physically configured to carry signals in one direction and to be incapable of carrying signals in the opposite direction; and an input path for conveying the stream of symbols from the input device of the remote user terminal to the processor of the secure installation, and an output path for conveying the graphical output from the processor of the secure installation to a display screen in the remote user terminal, wherein input and output paths are separate and independent paths, without electronic interaction between the input and output paths within the remote user terminal. receiving in a secure installation via a network from a remote user terminal an input comprising a stream of symbols that has been encrypted using a preselected encryption key; decoding the encrypted stream of symbols in the secure installation using a decryption key corresponding to the preselected encryption key, to produce a clear stream of symbols; using a computer program running on a processor in the secure installation, processing the symbols in the clear stream and generating a graphical output in a predefined display format in response to processing the symbols; and outputting the graphical output from the secure installation to the network, characterized in that: the stream of symbols from the remote user terminal exits an encryption circuit of an input device of the the remote user terminal through a one-way link within the input device that is physically configured to carry signals in one direction and to be incapable of carrying signals in the opposite direction; and an input path for conveying the stream of symbols from the input device of the remote user terminal to the processor of the secure installation, and an output path for conveying the graphical output from the processor of the secure installation to a display screen in the remote user terminal, wherein input and output paths are separate and independent paths, without electronic interaction between the input and output paths within the remote user terminal. the stream of symbols from the remote user terminal exits an encryption circuit of an input device of the the remote user terminal through a one-way link within the input device that is physically configured to carry signals in one direction and to be incapable of carrying signals in the opposite direction; and an input path for conveying the stream of symbols from the input device of the remote user terminal to the processor of the secure installation, and an output path for conveying the graphical output from the processor of the secure installation to a display screen in the remote user terminal, wherein input and output paths are separate and independent paths, without electronic interaction between the input and output paths within the remote user terminal.