# Constant-Time Encoding

[![Build Status](https://github.com/paragonie/constant_time_encoding/actions/workflows/ci.yml/badge.svg)](https://github.com/paragonie/constant_time_encoding/actions)
[![Latest Stable Version](https://poser.pugx.org/paragonie/constant_time_encoding/v/stable)](https://packagist.org/packages/paragonie/constant_time_encoding)
[![Latest Unstable Version](https://poser.pugx.org/paragonie/constant_time_encoding/v/unstable)](https://packagist.org/packages/paragonie/constant_time_encoding)
[![License](https://poser.pugx.org/paragonie/constant_time_encoding/license)](https://packagist.org/packages/paragonie/constant_time_encoding)
[![Downloads](https://img.shields.io/packagist/dt/paragonie/constant_time_encoding.svg)](https://packagist.org/packages/paragonie/constant_time_encoding)

Based on the [constant-time base64 implementation made by Steve "Sc00bz" Thomas](https://github.com/Sc00bz/ConstTimeEncoding),
this library aims to offer character encoding functions that do not leak
information about what you are encoding/decoding via processor cache 
misses. Further reading on [cache-timing attacks](http://blog.ircmaxell.com/2014/11/its-all-about-time.html).

Our fork offers the following enchancements:

* `mbstring.func_overload` resistance
* Unit tests
* Composer- and Packagist-ready
* Base16 encoding
* Base32 encoding
* Uses `pack()` and `unpack()` instead of `chr()` and `ord()`

## PHP Version Requirements

Version 2 of this library should work on **PHP 7** or newer. For PHP 5
support, see [the v1.x branch](https://github.com/paragonie/constant_time_encoding/tree/v1.x).

If you are adding this as a dependency to a project intended to work on both PHP 5 and PHP 7, please set the required version to `^1|^2` instead of just `^1` or `^2`.

## How to Install

```sh
composer require paragonie/constant_time_encoding
```

## How to Use

```php
use ParagonIE\ConstantTime\Encoding;

// possibly (if applicable): 
// require 'vendor/autoload.php';

$data = random_bytes(32);
echo Encoding::base64Encode($data), "\n";
echo Encoding::base32EncodeUpper($data), "\n";
echo Encoding::base32Encode($data), "\n";
echo Encoding::hexEncode($data), "\n";
echo Encoding::hexEncodeUpper($data), "\n";
```

Example output:
 
```
1VilPkeVqirlPifk5scbzcTTbMT2clp+Zkyv9VFFasE=
2VMKKPSHSWVCVZJ6E7SONRY3ZXCNG3GE6ZZFU7TGJSX7KUKFNLAQ====
2vmkkpshswvcvzj6e7sonry3zxcng3ge6zzfu7tgjsx7kukfnlaq====
d558a53e4795aa2ae53e27e4e6c71bcdc4d36cc4f6725a7e664caff551456ac1
D558A53E4795AA2AE53E27E4E6C71BDCC4D36CC4F6725A7E664CAFF551456AC1
```

If you only need a particular variant, you can just reference the 
required class like so:

```php
use ParagonIE\ConstantTime\Base64;
use ParagonIE\ConstantTime\Base32;

$data = random_bytes(32);
echo Base64::encode($data), "\n";
echo Base32::encode($data), "\n";
```

Example output:

```
1VilPkeVqirlPifk5scbzcTTbMT2clp+Zkyv9VFFasE=
2vmkkpshswvcvzj6e7sonry3zxcng3ge6zzfu7tgjsx7kukfnlaq====
```

## Support Contracts

If your company uses this library in their products or services, you may be
interested in [purchasing a support contract from Paragon Initiative Enterprises](https://paragonie.com/enterprise).

• [D] src
• [F] composer.json
  Delete
• [F] LICENSE.txt
  Delete
• [F] README.md
  Delete

Contact Section

Get in Touch with Us for Any Questions or Support

We’d love to hear from you! Whether you have questions, feedback, or need support, our team is here to help. Reach out to us via email, phone, or visit our office. We’re committed to providing you with exceptional service and ensuring your experience with NFC Pay is seamless and satisfying. Let’s connect!

Name*

Email*

Message*

Send Message

Our Location

20-22 Wenlock Road, England, N1 7GU

Call us on: +03601 885399

Our office hours Monday–Friday, 9am - 9pm

Email us directly

support@example.com