malloc + 4??

From: Kevin Torr (kevintorr_at_hotmail.com)
Date: 04/04/04 

Date: Mon, 5 Apr 2004 00:21:59 +1000

http://www.yep-mm.com/res/soCrypt.c

I have 2 malloc's in my program, and when I write the contents of them to
the screen or to a file, there aren addition 4 characters.

As far as I can tell, both the code to register the malloc and to write
information into the malloc is solid. Why then ismy program returning an
additional 4 characters?

register malloc 1:
line 192

register malloc 2:
line 214

write to malloc 1:
line 200 - 205

write to malloc 2:
line 221 - 225

display malloc 2:
line 157

write malloc 2:
line 251

Here's how you execute the program:

socrypt.exe /e :i input.txt :o output.txt :A keya.txt :B keyb.txt :k
keyout.txt

**note that the input, keya, and keyb files must exist or the program will
return an error code.

If you write a text string into the input.txt file, it will write the same
string into the output.txt file plus an addition 4 characters.

The 1024 char random 'masterkey' is also written out to the keyout.txt file
with an addition 4 characters.

Why is this happening? I'm totally baffled and have spent days trying to
figure this out.