<?php
    /**
     * Description of Cripty
     *
     * @author Lucas Awade
     */
    class Crypt {

        private $message;
        private $key;
        private $option;
        private $tag;
        private $cipher;
        private $ivlen;
        private $iv;
        private $textcrypt;

        const CONF_CIPHER_CRYPT = 'aes-256-cbc';

        function __construct($key = null, $cipher = null, $option = OPENSSL_RAW_DATA, $tag = null) {
            if (!$cipher) {
                $this->cipher = self::CONF_CIPHER_CRYPT;
            } else {
                $this->cipher = $cipher;
            }
            $this->key = $key;
            $this->option = $option;
            $this->tag = $tag;
            $this->openssl_crypt();
        }

        public function encrypt($message = null) {
            $this->setMessage($message);
            $encrypt = openssl_encrypt($this->message, $this->cipher, $this->key, $this->option, $this->iv);
            $hashcode = hash_hmac('sha256', $encrypt, $this->key, true);
            $this->textcrypt = base64_encode($this->iv . $hashcode . $encrypt);
            return $this->textcrypt;
        }

        public function decrypt($textcrypt = null) {
            $c = base64_decode($textcrypt);
            $this->iv = substr($c, 0, $this->ivlen);
            $hmac = substr($c, $this->ivlen, 32);
            $ciphertext_raw = substr($c, $this->ivlen + 32);
            $original_plaintext = openssl_decrypt($ciphertext_raw, $this->cipher, $this->key, $options = OPENSSL_RAW_DATA, $this->iv);
            $calcmac = hash_hmac('sha256', $ciphertext_raw, $this->key, true);
            if (hash_equals($hmac, $calcmac)) { 
                return $original_plaintext;
            }
        }

        private function openssl_crypt() {
            if (in_array(strtolower($this->cipher), openssl_get_cipher_methods())) {
                $this->ivlen = openssl_cipher_iv_length($this->cipher);
                $this->iv = openssl_random_pseudo_bytes($this->ivlen);
            }
        }

        public function setKey($key) {
            $this->key = $key;
        }

        public function setOption($option) {
            $this->option = $option;
        }

        public function setTag($tag) {
            $this->tag = $tag;
        }

        public function setMessage($message) {
            $this->message = $message;
        }

    }