From: jazz@hal.com (Jason Zions)
Date: Fri, 16 Sep 94 12:17:57 PDT
To: cypherpunks@toad.com
Subject: Re: if this is RC4
Message-ID: <9409161917.AA28174@jazz.hal.com>
MIME-Version: 1.0
Content-Type: text/plain


>> Decompilation would not preserve the original style.
>
>Of course it would. If a symbol table was present, you'd even end up
>with the same variable names.

Decompilation would not preserve stylistic things like indentation and brace
usage. With optimized compilers, it's getting pretty hard for a decompiler
to actually figure out the original input source statement. The result of a
decompile, when again compiled, may indeed produce the same object; but the
original and decompiled source code may look radically different.

The RC4 source code contains at least one example of a coding idiom that
would almost certainly decompile differently. In a couple instances, the
posted alleged-RC4 source takes modulo-256 of a particular value. A compiler
would in almost all cases emit code which did a simple logical-AND with
0xff; when decompiled, the C code would reflect that logical-AND rather than
a mod-256 operation.

It looked like real source to me, rather than decompiled.

Jason