Keith Petersen <W8SDZ@Simtel20.ARPA> (11/25/84)
Thanks to AIZ@JPL-VLSI.ARPA for contributing CIPH.LBR to our CP/M
collection. It's now available from Simtel20:
Filename Type Bytes CRC
Directory MICRO:<CPM.TXTUTL>
CIPH.LBR.1 COM 23296 E07AH
Here's what it is:
The Prototype AIZ Cipher/Encode/Wrap Program: CIPH
by A.I. Zygielbaum, June 4, 1984
The CIPH files contain the original CIPH.BAS file which is
written for MicroSoft BASIC Version 5 and a compiled CIPH.COM
file which will run on 8080 or Z80 systems.
CIPH is designed to encode (decode) ASCII files 1) to fold (and
unfold) all characters into (and out of) the printable ASCII set
and 2) to encrypt (decipher) files according to the BASIC random
number generator. The folding is simply a mapping that takes
parity set characters and control characters and transforms each
of them into two printable ASCII characters. This allows, for
example, WORDSTAR files to be transmitted via mail systems with
no loss of special or control characters.
The encryption algorithm is based upon the addition of a random
number to the ASCII value of each character in the file. The
BASIC randomization routine is preset with a seed derived from a
keyword. Naturally, once a file is encrypted using a keyword, it
can be deciphered only with the same keyword.
All commands in the program are prompted and consist of:
1. indicating encode or decode
2. specifying the input file
3. specifying the output file
4. giving the keyword, if required.
If no keyword is specified, then the program merely folds or
unfolds the file to or from the printable ASCII set.
This is a prototype program. Therefore, it has not been
optimized. It has been in used for many conversions with no
problem. An assembly language version is being written to speed
the conversions and also to allow direct interface with terminal
software.