Duplicating and ciphering device and methods for codification of facsimile telecopies

A duplicating and ciphering device in which, in order to retain the privacy of the document to be transmitted, the individual units of the duplicating and ciphering device are constructed as a duplicating machine, and annexation possibilities for an electronic memory for storing the information taken from the scanner and for a coding mechanism for coding this information. Such device can be used as a duplicating machine as well as a ciphering device for coding information before entering it into a fax machine. It is also suited to again emit incoming, encoded information in clear text. A method for coding facsimile telecopies is included whereby in sending, the original is scanned and transmitted line by line and at the receiving end a similar copy true to the original is printed out. In order to prevent confidential information from falling into the wrong hands, the content of the digital transmitted information is coded. A memory stores several dot rows and a coding mechanism, which interchanges the sequence of the stored dot rows and/or alters the relative position of the dot rows. The decoding follows then through entering a password or a coding card, for example.

The invention relates to a duplicating and ciphering device, consisting of 
an insert part, a scanner, which includes one or more dot rows, a printer 
with paper feed, and an output part. 
The invention has to do particularly with a device for the codification of 
facsimile telecopies, which when sent, the original is scanned in one or 
more dot rows and transmitted, and then when received, is printed in a 
copy that is true to the original. 
In recent years facsimile telecopies have been very successful and proven 
themselves extraordinarily. Today fax machines are in many cases replacing 
mail letters since facsimiles are received in a much shorter time. 
Unfortunately, it frequently occurs that mismailed letters are delivered at 
an incorrect address and thereby in certain circumstances confidential 
information becomes known. But confidential telecopies can also reach the 
wrong hands, so that in the broadest sense the inviolability of letters is 
no longer guaranteed. 
Devices are already known which by means of storing information received, 
prevents printing, and the printing is enabled only by use of a password. 
However this form of privacy of information does not always prevent 
misdirecting letters and the content of such telecopies falling into the 
wrong hands. Even so, the safe keeping of transmitted information at one 
stage is not possible without additional measures. To remedy this 
disadvantage, the invention includes a feature in which a simply produced 
duplicating and ciphering device is used as a simple duplicating machine 
as well as for coding information, before the information is entered into 
a fax machine, but which is also capable of putting incoming ciphered 
information back into clear text. 
Such a device can essentially consist of known parts of fax machines. They 
consist normally of an insertion part for the original, a scanner which 
scans one or more dot rows, a printer with paper feed, and an output part. 
This standard equipment allows the making of copies. According to the 
invention such standard equipment is combined with further module units 
and indeed with an electronic memory for storing the information taken 
from the scanner, and with a coding device for coding this information. 
In the patent application P 40 21 061.8 simple ciphering methods are 
described which are suited for use with a device according to the present 
invention. 
For entering a code into the coding device, a keyboard and/or a reading 
device from an input-output medium is provided, for example a magnetic 
card. 
Appropriately, the reading device is also developed for the coding of an 
input-output medium, for example a magnetic card. 
As a further means for remedying these disadvantages, the present invention 
includes a memory means for temporary storage of several dot rows, and 
connected with the memory device a coding device of such type that the 
order of the stored dot rows is transposed and/or the relative position of 
the dot rows is otherwise changed. 
If the dot rows were only pushed together, it could be determined from the 
beginning of a line how many dot units the dot rows were moved in the 
coding. 
To prevent that possibility of that being determined, it is provided that 
the empty spaces resulting from the alteration of the relative position of 
the dot rows be temporarily overlaid with dots by means of a random 
generator. 
The coding device must of course receive the desired code by means of a 
keyboard, whereby, in place of the keyboard or a complement thereof, a 
coding card is utilized, which by frequent repetition fixes the exchange 
and/or alteration of the relative position of the dot rows. 
In order to prevent even mismailed items from transmitting confidential 
information to an undesired location, according to the invention, the 
coding is arranged by the sender before transmitting. 
In such a case it is of course necessary that the receiver also have a 
coding device, which by means of a keyboard and/or a coding card, 
determines the exchange and/or alteration of the relative position of the 
dot rows. 
The provision of synchronized signals in regular intervals, for example 
after each eighth row, essentially simplifies the correct transmitting of 
information. 
Likewise a "Startcode" that can be set as desired simplifies the coding and 
decoding, since in this manner plain text and coded information can be 
mixed in sending or receiving. 
In order to make a fax machine user-friendly, the invention includes the 
feature that the same coding device is used for the coding as well as the 
decoding, which can be switched from "coding" to "decoding". 
Since most fax machines are also provided with the capacity to copy 
originals, the invention provides that a coded, printed copy can be 
transformed again into a copy true to the original after entering the 
coding, thereby essentially expanding the functions of a fax machine. 
Also after entering a "Receive" code, a revision of a strangely coded copy, 
which is not legible, can be issued true to the original when copied anew. 
Accordingly, the method of the invention also enables the storage of 
private information, which is only legible after renewed copying. With 
simple and known means a coding device can also be combined with a device 
that enables the storing of the code in the device or in an external 
storage place, for example in the form of a coding card. 
A simple example of facsimile-data transmission is described in the 
following.

The duplicating device 1 includes, in known form and as usual with a 
facsimile machine, a scanner, which scans one or several dot rows, and for 
the printout, a printer with paper feed and an accompanying output part. 
The original paper 2 is laid in known manner in the duplicating machine 1 
and scanned by the scanner. 
So long as the machine is used only for copies, the printer receives the 
information from the scanner and prints a corresponding copy. 
Should a ciphered copy be made, the information received by the scanner is 
directed to a memory 3 where it is stored. The memory 3 can be pre-coded 
in such manner by means of a keyboard 4 or a reading device 5 that it 
displaces and/or interchanges the lines of the stored information, which 
are in dot rows, as is described in German patent application No. P 40 21 
061.8 referred to above. 
Corresponding to the entered coding, the information now ciphered is put in 
by means of a memory 6 and issued from the printer as a ciphered copy. 
The advantage of a duplicating and ciphering machine according to the 
invention consists in that it can be used with any desired fax machine 
available on the market. No electric connection is needed, since the 
ciphered original can be entered directly into each fax machine. 
A further advantage is that for the use of such a machine no license from 
the postal or any other authority is required. 
A further feature of the invention is that other methods can also be used 
for the coding of information. Thus it is conceivable to use an eight 
digit code number for ciphering, with each entered digit determining the 
displacement in the individual dot rows as well as the vertical 
interchange of the dot rows. Such form of ciphering would essentially 
simplify the handling of the machine, but make the decoding significantly 
more difficult. 
As a data carrier, a programmable magnetic card was previously referred to, 
but other systems are also suitable for entering a corresponding ciphering 
code, such as, to name a few, magnetic strips, punch cards, or cards with 
bar code which can be prepared by hand. 
FIG. 2 shows a performance example in which a card 7, for example, by means 
of entering markings 8 with a ball point pen, specifies the position of 
each line or the displacement of the dot rows. The machine also allows the 
ciphering of ordinary texts or information which is not sent by fax. 
The simple construction of a duplicating and ciphering machine according to 
the invention makes possible in certain circumstances a portable 
operation, so that one could carry secret documents without running the 
danger that they might be understood, if stolen, for example. 
FIG. 3 shows the resolution of 8 dot rows which contain the word "FAXCODE". 
If these 8 dot rows should be separately stored in a memory according to 
the invention, and each dot row displaced corresponding to a code, for 
example, 1-5-7-2-5-3-6-0, corresponding to the dot count to which each dot 
row is displaced, the picture would be altered, as presented in FIG. 4. Of 
course the grid shown in FIGS. 3 to 6 would not be printed. However, the 
vertical line of the letter "F" would make discernible how many points the 
dot rows have been displaced. Thus it would be easy to recognize the code 
and thereby make it decipherable. 
In order to prevent this possibility, the points 9 would be inserted from a 
random generator and thereby not enable the displacement of the dot rows 
to be discerned. 
FIG. 5 shows another manner of coding, in which the rows are vertically 
interchanged. In this example, "3-6-5-1-4-8-2-7" corresponds to the 
exchanged order of the dot rows, which likewise yields an indiscernible 
picture. 
FIG. 6 shows finally the combination of both codes, that is, displacement 
of the rows with the resulting empty spaces filled by a random generator, 
and also interchange of the rows. FIG. 6 shows clearly that such a coding 
is practically impossible to decipher. With a coding of only 8 dot rows, 
and a maximum displacement of 8 points, over 16 million possibilities 
result, of which certainly not all would be meaningful, and combined with 
interchange of the rows, if one limits himself to meaningful combinations, 
this would increase the count of possibilities by a factor of 40,000, 
which would result in about 640,000 million combinations. 
In order to make the method most error free, it is provided that during the 
transmitting, a synchronizer impulse, for example each 8 or 16 dot rows, 
is transmitted also since this step is not utilized for the normal 
transmitting of facsimile information. The particular design example 
described includes only essential points and advantages of the method 
according to the invention. All meaningful additional adaptations for 
digital transmitting methods are optimally useful and possible. Also a 
limitation to the partial use of all the features of the invention, for 
reasons of simplification or cost, is possible. 
However ramification of the described example, through exclusion or 
addition of certain characteristics, fall within the broad scope of the 
invention.