PHP SSL Chunker

<?php

/**
 *
 * This content is released under the MIT License (MIT)
 *
 * @author	Don Myers
 * @license	http://opensource.org/licenses/MIT	MIT License
 * @link	https://github.com/ProjectOrangeBox
 */

class ssl
{
	public static function create(int $bits = 2048, string $folder = null): bool
	{
		$folder = ($folder) ? rtrim($folder, '/') : __DIR__;

		$public = $folder . '/public.key';
		$private = $folder . '/private.key';

		if (!is_writable($folder)) {
			throw new \Exception('Key folder is not writable.');
		}

		$config = [
			'private_key_bits' => $bits,
			'private_key_type' => OPENSSL_KEYTYPE_RSA,
		];

		$privateKey = openssl_pkey_new($config);

		openssl_pkey_export_to_file($privateKey, $private);

		$publicKey = openssl_pkey_get_details($privateKey);

		return file_put_contents($public, $publicKey['key']) > 0;
	}

	public static function encrypt(string $data, string $keyFile = null): string
	{
		$keyFile = ($keyFile) ?? __DIR__ . '/public.key';

		if (!file_exists($keyFile)) {
			throw new \Exception('Count not locate key file ' . basename($keyFile));
		}

		$key = openssl_pkey_get_public('file://' . $keyFile);

		if (!$key) {
			throw new \Exception('Could not get public key');
		}

		$details = openssl_pkey_get_details($key);

		$length = ceil($details['bits'] / 8) - 11;

		$output = '';

		while ($data) {
			$chunk = substr($data, 0, $length);
			$data = substr($data, $length);
			$encrypted = '';

			if (!openssl_public_encrypt($chunk, $encrypted, $key)) {
				throw new \Exception('Failed to encrypt data');
			}

			$output .= $encrypted;
		}

		return $output;
	}

	public static function decrypt(string $data, string $keyFile = null): string
	{
		$keyFile = ($keyFile) ?? __DIR__ . '/private.key';

		if (!file_exists($keyFile)) {
			throw new \Exception('Count not locate ' . basename($keyFile));
		}

		$key = openssl_pkey_get_private('file://' . $keyFile);

		if (!$key) {
			throw new \Exception('Could not get private key');
		}

		$details = openssl_pkey_get_details($key);

		$length = ceil($details['bits'] / 8);

		$output = '';

		while ($data) {
			$chunk = substr($data, 0, $length);
			$data = substr($data, $length);
			$decrypted = '';

			if (!openssl_private_decrypt($chunk, $decrypted, $key)) {
				throw new \Exception('Failed to decrypt data');
			}

			$output .= $decrypted;
		}

		return $output;
	}
} /* end class */