Browse Prior Art Database

Protecting Data Transmitted on Lines

IP.com Disclosure Number: IPCOM000059731D
Original Publication Date: 1986-Jan-01
Included in the Prior Art Database: 2005-Mar-08
Document File: 2 page(s) / 42K

Publishing Venue

IBM

Related People

Stadler, EE: AUTHOR

Abstract

A method is described which permits data transmitted on lines to be hardware-protected in a simple manner and which is preferably employed where line redundancy exists. Fig. 1 shows the principle of this method. The output of a random pulse signal generator is XORed with the computer data and then low- pass-filtered. The resultant pulse sequence is transmitted on one line, and the random pulse sequence on another. Fig. 1 also shows the receivers for pulse-shaping the transmitted signals, and the decoder. The latter XORs the pulse sequence with the random pulse signal, so that the original computer data reappear at the decoder output. Fig. 2 is an example of the timing diagram of possible pulse sequences obtained by this method.

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Protecting Data Transmitted on Lines

A method is described which permits data transmitted on lines to be hardware- protected in a simple manner and which is preferably employed where line redundancy exists. Fig. 1 shows the principle of this method. The output of a random pulse signal generator is XORed with the computer data and then low- pass-filtered. The resultant pulse sequence is transmitted on one line, and the random pulse sequence on another. Fig. 1 also shows the receivers for pulse- shaping the transmitted signals, and the decoder. The latter XORs the pulse sequence with the random pulse signal, so that the original computer data reappear at the decoder output. Fig. 2 is an example of the timing diagram of possible pulse sequences obtained by this method. The first line from the top shows the original computer data, the second the random pulse sequence, the third the XORed pulse sequence, the fourth the filtered signal, and the last the recovered computer data. Transmitting further random pulse sequences on additional lines or physically separating the individual line cores from each other renders the data handled more secure against tapping or eavesdropping.

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