[ydl-gen] [YDL5] Install DVD won't boot (bad media?) and related questions

[R. Hirschfeld]

> Date: Fri, 13 Apr 2007 06:15:11 -0400
> From: Derick Centeno <aguilarojo at verizon.net>

> Apple even entirely removed md5sum from 
> Darwin, the open source or BSD component of OS X which is standard 
> everywhere else (in every other Unix).

I believe md5sum is the GPL'd utility and md5 is the BSD-licensed
implementation.  If you want md5sum instead in MacOS, you can get it
via MacPorts or Fink (or compile it yourself).

> As I explained, and this is stated by Apple itself under it's help menu 
> -- Apple doesn't use md5sum, it uses another algorithm related to md5sum.
> The bottom line is that all the algorithms Apple uses don't match the 
> standard md5sum -- so none of the algorithm variants which Apple now 
> uses matter as far as YDL, or any other Linux, and maybe any other Unix, 
> is concerned.  None of the variants will produce a sequence ever 
> matching a md5sum standard.

I suspect you're mistaken about this (but can't check because I don't
have MacOS X): md5 and md5sum are different implementations of the
same algorithm and should produce identical results.

Is it possible that you mean that Apple has abandoned MD5 in favor of
another hash algorithm, such as SHA-1?  I hadn't heard that but I
suppose it might make sense because the security of md5 has been
broken (it is now computationally feasible to produce differing files
with the same md5 checksum).  So MD5 should probably not be used if
there's concern about possible malicious tampering and not just
transmission errors.  The md5sum and sha1sum programs use different
algorithms and will produce different results (both are part of the
GNU coreutils package).

Ray