I decided to follow the advice. I implemented the very famous (and simple)
sysmetric-key encryption scheme (too bad I forget the name of it). It is
theoreticaly unbreakable (in ideal conditions) if the key is long enough and
the data is truely random.
Max
// Encryption with a ascii string KEY with null-termination
// The source and encrypted data have same length: len
// Set encrypt to true to encrypt, false to decrypt
Err MyEnc(UInt8 *src, UInt8 *des, UInt8 *key, UInt16 len, Boolean encrypt)
{
UInt8 *srcP, *keyP, *desP;
UInt16 count=len;
Int16 tmp;
srcP=src; keyP=key; desP=des;
if(*keyP == '\0') return 1; // zero key length
while(count) {
if (*keyP == '\0')
keyP = key;
if(encrypt) {
tmp = *srcP + *keyP;
if(tmp > 255)
tmp -= 256;
} else {
tmp = *srcP - *keyP;
if(tmp < 0)
tmp += 256;
}
*desP = (UInt8)tmp;
count--; srcP++; desP++; keyP++;
}
return 0;
}
--- Joe Programmer <[EMAIL PROTECTED]> wrote:
> However, it would be better to heed Keith's advice and
> not use unsupported functions which could disappear
> with any new ROM release.
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