# 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

Blog Section

Discover the Latest in Digital Payments and NFC Technology

Dive into our blog to explore the cutting-edge trends in digital payments and NFC technology. Stay updated on the innovations that are revolutionizing transactions, boosting security, and making payments quicker and more convenient. Learn how these advancements are shaping the future of financial interactions and driving the global transition towards a cashless world.

The Rise of Contactless Payments:...

In recent years, contactless payments have surged in popularity, driven...

Visit Blog

March 27, 2024

Enhancing Payment Security: The Role...

As digital transactions proliferate, ensuring robust payment security is more critical than ever. Two foundational...

Visit Blog

March 27, 2024

The Future of Digital Wallets:...

Digital wallets have fundamentally transformed how we manage money, offering a streamlined, secure, and highly...

Visit Blog

March 27, 2024