Mcrypt-problems

Hi! I'm trying to encrypt some password using TripleDES-encryption here... I've followed the documentation for the mcrypt-libraries, but I get a warning (all though it -does- encrypt the text) every time I try to encrypt something; Warning: attempt to use an empty IV, which is NOT recommend My encrypt line looks like this: $crypted_password = mcrypt_ecb(MCRYPT_TripleDES, "secret key", $password, MCRYPT_ENCRYPT); If I echo bin2hex($crypted_password) i get output, so it seems to work... I'd just like to know why this warning appears... I'm using Apache 1.3.23, php 4.1.1. Here's the mcrypt version information: Mcrypt v.2.5.10 (i686-pc-linux-gnu) Linked against libmcrypt v.2.4 (the mcrypt-packages are the current available libmcrypt/mcrypt-packages in debian testing) -- Trond Arve Nordheim - "This message is ROT13-encrypted twice for extra security."