missing files in 4.3.0 (Crypt/HCEMD5.php)

I am in the process of upgrading the PHP on our network appliance product (http://www.net-itech.com/america/products/pd_products.htm) from 4.2.0 to 4.3.4, and it seems that a file named Crypt/HCEMD5.php (which used to be in the "pear" directory of the PHP distribution and is needed by Horde, apparently) has gone missing at version 4.3.0. I tried finding information about this using CVS, but the file has been moved by hand in the CVS repository, losing historical information ("cvs co -rphp-4_2_0 php-src" will *not* give you the same thing as the PHP 4.2.0 tarball). I browsed http://pear.php.net/ left and right, and couldn't find the package containing this file. Googling around, I found http://docs.akbkhome.com/pear/Crypt_HCEMD5.html and some messages of people with the same problem as I have now, without answers. I'm prepared to download all the PEAR packages that could be needed, but I can't even find the right one! Any idea? -- Pierre Phaneuf Mad Scientist, NITI R&D