PHP Encryption/Decryption done right (PHP 5.3+)

encrypt_decrypt_with_mcrypt.php

<?php
    /**
     * Returns an encrypted & utf8-encoded
     */
    function encrypt($pure_string) {
        $encryption_key = 'random_string_here_as_private_key';
        $iv_size = mcrypt_get_iv_size(MCRYPT_BLOWFISH, MCRYPT_MODE_ECB);
        $iv = mcrypt_create_iv($iv_size, MCRYPT_RAND);
        $encrypted_string = mcrypt_encrypt(MCRYPT_BLOWFISH, $encryption_key, utf8_encode($pure_string), MCRYPT_MODE_ECB, $iv);
        return $encrypted_string;
    }

    /**
     * Returns decrypted original string
     */
    function decrypt($encrypted_string) {
        $encryption_key = 'random_string_here_as_private_key';
        $iv_size = mcrypt_get_iv_size(MCRYPT_BLOWFISH, MCRYPT_MODE_ECB);
        $iv = mcrypt_create_iv($iv_size, MCRYPT_RAND);
        $decrypted_string = mcrypt_decrypt(MCRYPT_BLOWFISH, $encryption_key, $encrypted_string, MCRYPT_MODE_ECB, $iv);
        return $decrypted_string;
    }