src/Zend/Filter/Encrypt/Openssl.php
public function setEnvelopeKey($key)
    {
        if (is_array($key)) {
            foreach($key as $type => $option) {
                if ($type !== 'envelope') {
                    $key['envelope'] = $option;
                    unset($key[$type]);
                }
            }
        } else {
            $key = array('envelope' => $key);
        }

        return $this->_setKeys($key);
    }
public function setEnvelopeKey($key)
    {
        if (is_array($key)) {
            foreach($key as $type => $option) {
                if ($type !== 'envelope') {
                    $key['envelope'] = $option;
                    unset($key[$type]);
                }
            }
        } else {
            $key = array('envelope' => $key);
        }

        return $this->_setKeys($key);
    }
Sets envelope keys

@param  string|array $options Envelope keys
@return Zend_Filter_Encrypt_Openssl