|  | G |
SECTION G — PHYSICS

INSTRUMENTS

|  | G09 |
EDUCATING; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS

|  | G09C |
CODING OR CIPHERING APPARATUS FOR CRYPTOGRAPHIC OR OTHER PURPOSES INVOLVING THE NEED FOR SECRECY (secret transmission Fulltext... Hierarchy... Expanded...H04K; arrangements for transmitting secret digital information Fulltext... Hierarchy... Expanded...H04L 9/00)

|  | G09C 1/00 |
Apparatus or methods whereby a given sequence of signs, e.g. an intelligible text, is transformed into an unintelligible sequence of signs by transposing the signs or groups of signs or by replacing them by others according to a predetermined system (cryptographic typewriters Fulltext... Hierarchy... Expanded...G09C 3/00)

|  | G09C 1/02 |
· | by using a ciphering code in chart form

|  | G09C 1/04 |
· | with sign carriers or indicators moved relative to one another to positions determined by a permutation code or key, so as to indicate the appropriate corresponding clear or ciphered text

|  | G09C 1/06 |
· | wherein elements corresponding to the signs making up the clear text are operatively connected with elements corresponding to the signs making up the ciphered text, the connections, during operation of the apparatus, being automatically and continuously permuted by a coding or key member

|  | G09C 1/08 |
· · | the connections being mechanical

|  | G09C 1/10 |
· · | the connections being electrical

|  | G09C 1/12 |
· · · | comprising contact-bearing permutation discs

|  | G09C 1/14 |
· · | involving removable or interchangeable coding numbers, e.g. master tapes, punched cards

|  | G09C 3/00 |
Typewriters for ciphering or deciphering cryptographic text (marking record carriers Fulltext... Hierarchy... Expanded...G06K)

|  | G09C 3/02 |
· | with auxiliary keys or keyboards acting on the original keys or keyboards

|  | G09C 3/04 |
· | wherein the operative connections between the keys and the type-bars are automatically and continuously permuted, during operation, by a coding or key member

|  | G09C 3/06 |
· · | the connections being mechanical

|  | G09C 3/08 |
· · | the connections being electrical

|  | G09C 3/10 |
· · | involving removable or interchangeable coding members, e.g. master tapes, punched cards

|  | G09C 5/00 |
Ciphering apparatus or methods not provided for in the preceding groups, e.g. involving the concealment or deformation of graphic data such as designs, written or printed messages