*** Info file for NDcode (1.3) - 15 July 1997 ***

*** NDcode is also available for the Psion S5 ***

DESCRIPTION

NDcode is a MacSys macro to eNCode or DeCode strings of text. Use NDcode to selectively encrypt sensitive pieces of information of up to 250 characters in length. Therefore, select the desired text. If the selected string is too long the macro will warn you and stop. Make sure there are no "Enters" (paragraph ends) in your selection, since this will result in encryption of only the part in front of the first "Enter" and loss of the rest of the selection. When you want line feeds in your selection use <Shift-Enter> instead. After selection hit NDcode's hot-key. The macro will prompt you for a password that it uses in the subsequent encryption computation. The result is an unreadable string of characters that replaces the original text.   

For decryption, NDcode offers two alternatives. Select the string, hit the hot-key and enter the password. Make sure to select all (no more and no less) characters of this string (the strings will always start with ">>>" and end with "<<<"). The decrypted string will replace the encoded string, but will be shown underlined, while a dialog in the bottom-right corner of the screen will prompt you to ENcode the string again, to DEcode or to delete the string.
For normal use however, NDcode shows the translated code in a window and leaves the encrypted string in place. Therefore, place the cursor anywhere in front of the opening ">>>", and hit the hot-key. The windowed display can only show strings of 60 characters. With longer strings, NDcode will prompt you to use the selection method.

NDcode (1.1) and (1.2)/(1.3) use slightly modified encryption methods. These allow password verification. "Back-translation" of encrypted strings using a password different from the one used to encode, as was possible in (1.0), is no longer allowed. This way non-recoverable double encryption will be prevented. For upgraders this has the disadvantage that codes encrypted with NDcode (1.0) cannot be decrypted with newer versions. For security reasons I had to modify the encryption method again in (1.2), so that also encryptions done with (1.1) cannot be decrypted with (1.2). I hope this to be the last encryption modification necessary - Sorry for the inconvenience.

The password is case sensitive, may be from 1 to 8 characters long, and contain all characters that can be entered from the keybord. The password is nowhere stored on the machine, which adds to NDcode's security. I don't claim the encrypted information to be unbreakable, but I'm convinced that the encryption is a lot safer than the password protection offered by some other programs. 


DISCLAIMER

I've used NDcode on my English 1 Mb Psion 3a, where it performed flawlessly. However, needless to say, I don't give guarantees and you cannot hold me responsible in case anything goes wrong. If you forget the password used for encryption there is no way to retrieve the encoded information.

I cannot anticipate how often I'll upload future updates. I'm hesitant to stress the sysops of the Psion websites with too many updates and I certainly don't want to tire users with "daily" minor updates. However, when you send me your E-mail address, I'll add your name to a list of NDcode users who will receive all future (major and minor) updates by E-mail.

NDcode is freeware. You are free to use, modify and copy the macro. The only "rule" I would like you to observe is to pass only the unmodified version of NDcode, including this TXT file, on to others.


INSTALLATION

Copy NDCODE.MCR to directory \MACRO\MCR\. Open Tom Dolbilin's MACRO (MacSys), open NDCODE.MCR (Psion-e) and translate it (Psion-t). After installation assign a convenient hot-key (I use <Ctrl-Psion-x>). NDcode is now ready for use.


UPDATES

(1.0) First release.

(1.1) Added window view and password verification. V.1.0 codes cannot be decrypted using v.1.1.

(1.2) Code searches are now possible from anywhere in front of the code string, not only from the line where the code is on.
Again modified the encryption method to increase security. It is now no longer possible to deduce if only one password was used for different encryptions or that several different passwords were used. Encryptions made by v.1.0 or v.1.1 are not compatible! 

(1.3) Added possibility to Encode, DEcode or delete a selected string after decryption. 
Added functions so that it can be used as a plug-in of ExAb.

Enjoy NDcode. If you like the macro, please, give me feed-back. Any comment, suggestion and critisism is welcome. 

When you are looking for a program that stores your secret codes in a database, try my macro CodeSafe. Another macro I wrote is ExAb. It is a program for extension of your self-defined abbreviations into text strings or blocks.

Thanks to Tom Dolbilin for his excellent MACRO program.

Huub Linthorst
E-mail: linthors@chem.leidenuniv.nl