So I came up with this simple encrypt/decrypt algorythm:
void code(char *in, int size)
while(x < size)
in[x++] += in[x] < 64? 64: -64;
...and it works about 95%-99% correctly!!! Why?
When I fread into a buffer, "code()", fwrite, then repeat the process, opening the file to view it I notice some characters have changed into sort of wing-dings. Not what I intended...and it absolutely corrupts image files because of this...