It is essential that you verify the integrity of the downloaded
       files using the PGP or MD5/SHA files.  Please read Verifying
       HTTP Server Releases for more information on why you
       should verify our releases.
    The PGP signatures can be verified using PGP or GPG. First
       download the Xerces-C++ KEYS
       as well as the .asc signature file for the particular
       distribution.  Make sure you get these files from the main distribution
       directory, rather than from a mirror. Then verify the
       signatures using:
|  |  |  | 
|  | 
% pgpk -a KEYS
% pgpv <distribution-name>.asc
 |  | 
|  |  |  | 
or
|  |  |  | 
|  | 
% pgp -ka KEYS
% pgp <distribution-name>.asc
 |  | 
|  |  |  | 
or
|  |  |  | 
|  | 
% gpg --import KEYS
% gpg --verify <distribution-name>.asc
 |  | 
|  |  |  | 
Alternatively, you can verify the digests on the files. A
       command line program called md5 or md5sum
       is included in most UNIX distributions.  It is also available as
       part of GNU
       Textutils.  Windows users can get binary md5 programs from here, here, or
       here.