User.php

<?php

// [...]

/**
 * Generate a random hexadecimal token by hashing the current time in microseconds as float
 * 
 * @return string Random 32-characters long hexadecimal token
 */
public static function generateToken() {
    return md5(microtime(true));
}

/**
 * Check if the confirmation_token field in the database is NULLed or not
 *
 * @return bool Whether the user has confirmed his e-mail address or not
 */
public function hasConfirmed() {
    return $this->confirmation_token === null ? true : false;
}

/**
 * Try to confirm the user's e-mail address using the provided token
 * 
 * @param $token string The user-provided token
 * @return bool Whether the confirmation succeed or not.
 */
public function confirm($token) {
    // If the user has already confirmed we can't confirm him again.
    if ($this->hasConfirmed()) return false;

    if ($token === $this->confirmation_token) {
        // User has confirmed his e-mail address.
        $this->confirmation_token = null;
        $this->confirmed_at = \Carbon\Carbon::now();
        $this->save();

        return true;
    }

    // Token was incorrect.
    return false;
}

/**
 * Try to unconfirm the user's e-mail address
 * 
 * @return bool Whether the unconfirmation succeed or not.
 */
public function unconfirm() {
    // If the user is not even confirmed we can't unconfirm him.
    if (!$this->hasConfirmed()) return false;

    // Reset token with a newly generated one and save the model.
    $this->confirmation_token = User::generateToken();
    $this->confirmed_at = null;
    $this->save();

    return true;
}

// [...]