I am able to encrypt and decrypt on each machine, but the encrypted data can only be decrypted on that 
machine. I'm guessing this is an issue with the version of mcrypt. This is very disterbing as I have 
thousands of encrypted emails of customers. As I have no key to them I will never be able to upgrade mcrypt 
w/o this bug being resolved.

Machine 1:
kernel-2.2.17-21mdk
php version: 4.2.0
# rpm -qa | grep mcrypt
libmcrypt-2.4.4-1
libmcrypt-devel-2.4.18-2

Machine 2:
kernel-2.4.18.1mdk-1-1mdk
# rpm -qa | grep mcrypt
libmcrypt4-2.5.1-1mdk
libmcrypt4-devel-2.5.1-1mdk
php-mcrypt-4.2.1-4mdk

encrypt.php:
<?

$file = './test.txt';

$fp = fopen($file, "r");
$buf = fread($fp, filesize($file));
fclose($fp);
## echo $buf;

$tmp = '123456789012345678901234';
$buf = blowfish_encrypt($buf, $tmp);
echo "md5 on encrypted data: " . md5($buf) . "\n";

$fp = fopen($file . "_enc", "w");
fwrite ($fp, $buf);
fclose($fp);


function blowfish_encrypt($data, $pass) {

  if (strlen($pass) > 24) $pass = substr($pass, 0 , 24);
  if (strlen($pass) < 24) $pass = str_pad($pass, 24, 'this is a very secret pad');

  $td = mcrypt_module_open (MCRYPT_BLOWFISH, "", MCRYPT_MODE_ECB, "");
  $iv = mcrypt_create_iv (mcrypt_enc_get_iv_size ($td), MCRYPT_RAND);
  mcrypt_generic_init ($td, $pass, $iv);
  $out = mcrypt_generic ($td, $data);
  mcrypt_generic_end ($td);
  return $out;
}

?>

decrypt.php:
<?
$file = './test.txt_enc';

$fp = fopen($file, "r");
$buf = fread($fp, filesize($file));
fclose($fp);

echo "md5 on encrypted data: " . md5($buf) . "\n";

$pass = '123456789012345678901234';
$buf = blowfish_decrypt($buf, $pass);
echo $buf . "\n";

function blowfish_decrypt($data, $pass) {
  if (strlen($pass) > 24) $pass = substr($pass, 0 , 24);
  if (strlen($pass) < 24) $pass = str_pad($pass, 24, 'this is a very secret pad');

  $td = mcrypt_module_open (MCRYPT_BLOWFISH, "", MCRYPT_MODE_ECB, "");
  $iv = mcrypt_create_iv (mcrypt_enc_get_iv_size ($td), MCRYPT_RAND);
  mcrypt_generic_init ($td, $pass, $iv);
  $out = mdecrypt_generic ($td, $data);
  mcrypt_generic_end ($td);

  ## remove trailing 0 chars that blowfish adds
  return preg_replace('/\0*$/', '', $out);

}
?>

test.txt can be anothing, I used:
"## Created: 2002-07-10 14:46:21\n"


machine 1:
# php -q encrypt.php
md5 on encrypted data: 513f9ac2b549be9a8f54aec53f899545
# php -q decrypt.php
md5 on encrypted data: 513f9ac2b549be9a8f54aec53f899545
## Created: 2002-07-10 14:46:21

#

machine 2:
# php -q encrypt.php
md5 on encrypted data: 1f4f2599844f29ef765583838cf6e553
# php -q decrypt.php
md5 on encrypted data: 1f4f2599844f29ef765583838cf6e553
## Created: 2002-07-10 14:46:21

#

[copied machine 1 test.txt_enc to this machine]
# php -q decrypt.php
md5 on encrypted data: 513f9ac2b549be9a8f54aec53f899545
?DHd???PX????5?D?
#