Mcrypt Function - New to it

Hi there..some what a new programmer when it comes to all this. I'm trying to encrypt some data and then decrypt it. It doesn't have to be high bit encryption just something simple like 3DES. But I keep getting it wrong. Any help would be greatful. Here's the piece of code: $iv = mcrypt_create_iv (mcrypt_get_iv_size (MCRYPT_3DES,

MCRYPT_MODE_ECB), MCRYPT_RAND);              

$key = md5("Secret Key"); $sample2 = "Hello"; $lockdata = mcrypt_encrypt (MCRYPT_3DES, $key, $sample2,

MCRYPT_MODE_ECB, $iv);            

echo "$lockdata\n"; $text = mcrypt_decrypt (MCRYPT_3DES, $key, $lockdata, MCRPYT_MODE_ECB,

$iv);              

echo "$text\n";