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# Constant-Time Encoding |
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|
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[](https://travis-ci.org/paragonie/constant_time_encoding](https://travis-ci.org/paragonie/constant_time_encoding](https://travis-ci.org/paragonie/constant_time_encoding) |
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|
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Based on the [](https://github.com/Sc00bz/ConstTimeEncodingconstant-time base64 implementation made by Steve "Sc00bz" Thomas](https://github.com/Sc00bz/ConstTimeEncoding](https://github.com/Sc00bz/ConstTimeEncoding), |
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this library aims to offer character encoding functions that do not leak |
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information about what you are encoding/decoding via processor cache |
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misses. Further reading on [](http://blog.ircmaxell.com/2014/11/its-all-about-time.htmlcache-timing attacks](http://blog.ircmaxell.com/2014/11/its-all-about-time.html](http://blog.ircmaxell.com/2014/11/its-all-about-time.html). |
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|
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Our fork offers the following enchancements: |
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|
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* `mbstring.func_overload` resistance |
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* Unit tests |
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* Composer- and Packagist-ready |
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* Base16 encoding |
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* Base32 encoding |
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* Uses `pack()` and `unpack()` instead of `chr()` and `ord()` |
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|
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## PHP Version Requirements |
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|
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This library should work on any [](https://secure.php.net/supported-versions.phpsupported version of PHP](https://secure.php.net/supported-versions.php](https://secure.php.net/supported-versions.php). |
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It *may* work on earlier versions, but we **do not** guarantee it. If it |
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doesn't, we **will not** fix it to work on earlier versions of PHP. |
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|
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## How to Install |
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|
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```sh |
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composer require paragonie/constant_time_encoding |
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``` |
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|
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## How to Use |
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|
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```php |
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use \ParagonIE\ConstantTime\Encoding; |
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|
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// possibly (if applicable): |
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// require 'vendor/autoload.php'; |
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|
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$data = random_bytes(32); |
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echo Encoding::base64Encode($data), "\n"; |
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echo Encoding::base32EncodeUpper($data), "\n"; |
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echo Encoding::base32Encode($data), "\n"; |
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echo Encoding::hexEncode($data), "\n"; |
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echo Encoding::hexEncodeUpper($data), "\n"; |
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``` |
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|
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Example output: |
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|
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``` |
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1VilPkeVqirlPifk5scbzcTTbMT2clp+Zkyv9VFFasE= |
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2VMKKPSHSWVCVZJ6E7SONRY3ZXCNG3GE6ZZFU7TGJSX7KUKFNLAQ==== |
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2vmkkpshswvcvzj6e7sonry3zxcng3ge6zzfu7tgjsx7kukfnlaq==== |
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d558a53e4795aa2ae53e27e4e6c71bcdc4d36cc4f6725a7e664caff551456ac1 |
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D558A53E4795AA2AE53E27E4E6C71BDCC4D36CC4F6725A7E664CAFF551456AC1 |
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``` |
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|
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If you only need a particular variant, you can just reference the |
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required class like so: |
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|
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```php |
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use \ParagonIE\ConstantTime\Base64; |
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use \ParagonIE\ConstantTime\Base32; |
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|
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$data = random_bytes(32); |
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echo Base64::encode($data), "\n"; |
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echo Base32::encode($data), "\n"; |
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``` |
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|
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Example output: |
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|
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``` |
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1VilPkeVqirlPifk5scbzcTTbMT2clp+Zkyv9VFFasE= |
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2vmkkpshswvcvzj6e7sonry3zxcng3ge6zzfu7tgjsx7kukfnlaq==== |
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``` |
