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PHP Constant Time String Encoding: Encode text without leaking context information

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2019-02-12 (1 month ago) RSS 2.0 feedNot yet rated by the usersTotal: 68 This week: 30All time: 9,357 This week: 14Up
Version License PHP version Categories
constant_time_encodi 1.0MIT/X Consortium ...5PHP 5, Text processing
Description Author

This package can encode and decode text without leaking context information.

It provides pure PHP based functions that encode and decode without leaking information about what you are encoding and decoding via processor cache misses.

Currently it provides functions to encode and decode data using the algorithms for base64, base32, base16 and hexadecimal.

Innovation Award
PHP Programming Innovation award nominee
February 2019
Nominee
Vote
Constant time encoding is an approach to generate variable data that takes the same length of time regardless of the data that it is generating.

This is important because if different data values passed to code that implements a given processing algorithm take a variable length of time to run, it may help to expose secret values that the algorithm is using, thus compromising the security of the system.

This package provides an implementation of several data encoding algorithms in pure PHP code, in such a way that they always take the same length of time to execute regardless of the data that it is processing, thus providing more security protection to applications that use this package.

Manuel Lemos
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Name: Scott Arciszewski <contact>
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Country: United States United States
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Nominee: 12x

Winner: 1x

Details

Constant-Time Encoding

Build Status Latest Stable Version Latest Unstable Version License Downloads

Based on the constant-time base64 implementation made by Steve "Sc00bz" Thomas, 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.

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.

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

composer require paragonie/constant_time_encoding

How to Use

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:

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.

  Files folder image Files  
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Files folder imagesrc (11 files)
Files folder imagetests (9 files)
Accessible without login Plain text file .travis.yml Data Auxiliary data
Accessible without login Plain text file composer.json Data Auxiliary data
Accessible without login Plain text file LICENSE.txt Doc. Documentation
Accessible without login Plain text file phpunit.xml.dist Data Auxiliary data
Accessible without login Plain text file psalm.xml Data Auxiliary data
Accessible without login Plain text file README.md Doc. Documentation

  Files folder image Files  /  src  
File Role Description
  Accessible without login Plain text file Base32.php Class Class source
  Accessible without login Plain text file Base32Hex.php Class Class source
  Accessible without login Plain text file Base64.php Class Class source
  Accessible without login Plain text file Base64DotSlash.php Class Class source
  Accessible without login Plain text file Base64DotSlashOrdered.php Class Class source
  Accessible without login Plain text file Base64UrlSafe.php Class Class source
  Accessible without login Plain text file Binary.php Class Class source
  Accessible without login Plain text file EncoderInterface.php Class Class source
  Accessible without login Plain text file Encoding.php Class Class source
  Accessible without login Plain text file Hex.php Class Class source
  Accessible without login Plain text file RFC4648.php Class Class source

  Files folder image Files  /  tests  
File Role Description
  Accessible without login Plain text file Base32HexTest.php Class Class source
  Accessible without login Plain text file Base32Test.php Class Class source
  Accessible without login Plain text file Base64DotSlashOrderedTest.php Class Class source
  Accessible without login Plain text file Base64DotSlashTest.php Class Class source
  Accessible without login Plain text file Base64Test.php Class Class source
  Accessible without login Plain text file Base64UrlSafeTest.php Class Class source
  Accessible without login Plain text file EncodingTest.php Class Class source
  Accessible without login Plain text file HexTest.php Class Class source
  Accessible without login Plain text file RFC4648Test.php Class Class source

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