ZCRYPT - Simple Encryption Engine
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Files in the archive:
  ZCRYPT.83P		compiled ZCRYPT program (unsquished)
  ZZCRYPT.83P		compilec ZCRYPT program (squished)
  ZCRYPT.ASM		source code of ZCRYPT
  README.TXT		this ReadMe-File


ZCRYPT is an ASM-Program to encrypt/decrypt strings by using a XOR-Encryption.
You can use ZCRYPT in your program to encrypt savegames, program data etc.

Two variables are needed as input:
  X		the Key to encrypt/decrypt (should be deleted after use!)
  Str0		the input/output of ZCRYPT (warning: Str0 will be overwritten)

It hasn't to be specified if encryption or decryption should be used. Because of
the XOR-Encryption uencrypted data will be encrypted and encrypted data will be
decrypted (if you got the right key *gg*).

The Encryption is based on TI's random number generator. Characters of the input
string will be XOR-encrypted with a random number. Because the random numbers are
not really random (the TI-83 uses a pseudo-random number generator), it has to
be initialized with a number. This number is the Key. When you get two "random"
numbers with the same initialization, these numbers would be the same! This is why
the encryption algorithm works.
If anybody has got some information about the random number generator on the TI-83
please mail it to me.

ZCRYPT can be modified to work with programs instead of strings very easily. See
ASM83-Guru Tutorials 16 & 17 for more details.

ZCRYPT runs in silent mode. That means that nothing is displayed on the screen if you
run it. But please remember the use of ZCRYPT in the credits of your program...


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ZCRYPT - Copyright (c) 2003 Zykure, zykure@web.de


Visit my homepage at http://www.zykure.de