Image:USpatent1310719.fig1.png

From Wikipedia, the free encyclopedia

Image
File history
File links

Size of this preview: 419 × 600 pixels
Full resolution‎ (443 × 634 pixels, file size: 58 KB, MIME type: image/png)

Vernam cipher patent, Figure 1. This drawing shows Gilbert Vernam's original concept for a teletype encryption machine that combines plaintext characters (C) with characters on a key paper tape (D) using an XOR function. The XOR takes place at relays 19 through 25. If both the C and D contacts are open, no voltage is applied to the relay coil. If both C and D contacts are closed, voltage is applied to both ends of the relay coil, so the relay contacts stay open. If just one of contacts C and D are closed, current flows through the relay coil, closing its contact.

In general, the contents of United States patents are in the public domain.[1]

In specific cases, patent applicants and holders may claim copyright in portions of those documents. In those specific cases, applicants are required to identify the portions that are protected under copyright, and are additionally required to state the following within the body of the application and patent:[2] [3]

A portion of the disclosure of this patent document contains material which is subject to (copyright or mask work) protection. The (copyright or mask work) owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all (copyright or mask work) rights whatsoever.

The original patent should be checked for the presence of such language before an assumption is made that the contents are in the public domain.