# 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

About Section

About NFC Pay: Our Story and Mission

NFC Pay was founded with a vision to transform the way people handle transactions. Our journey is defined by a commitment to innovation, security, and convenience. We strive to deliver seamless, user-friendly payment solutions that make everyday transactions effortless and secure. Our mission is to empower you to pay with ease and confidence, anytime, anywhere.

• Simplifying Payments, One Tap at a Time.
• Reinventing Your Wallet for Modern Convenience.
• Smart Payments for a Effortless Lifestyle.
• Experience the Ease of Tap and Pay.
• Innovative Solutions for Your Daily Transactions.

FAQ Section

Frequently Asked Questions About NFC Pay

Here are answers to some common questions about NFC Pay. We aim to provide clear and concise information to help you understand how our platform works and how it can benefit you. If you have any further inquiries, please don’t hesitate to contact our support team.

How do I register for NFC Pay?

Download the app and sign up using your email or phone number, then complete the verification process.

Is my payment information secure?

Yes, we use advanced encryption and security protocols to protect your payment details.

Can I add multiple cards to my NFC Pay wallet?

Absolutely, you can link multiple debit or credit cards to your wallet.

How do I transfer money to another user?

Go to the transfer section, select the recipient, enter the amount, and authorize the transfer.

What should I do if I forget my PIN?

Use the “Forgot PIN” feature in the app to reset it following the provided instructions.

How can I activate my merchant account?

Sign up for a merchant account through the app and follow the setup instructions to start accepting payments.

Can I track my payment status?

Yes, you can view and track your payment status in the account dashboard