PHP 8 reference · String Functions

PHP bin2hex() Function

Convert binary data to a hexadecimal string, two hex digits per byte. Often used to print random bytes as a token.

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Syntax

bin2hex(string $string): string

Parameter	Description
`string`	The input string.

The hex string, twice as long as the input.

To hex and backTry it yourself

<?php
echo bin2hex("abc"), "\n";
echo hex2bin("616263"), "\n";

Output

616263
abc

A random tokenTry it yourself

<?php
$token = bin2hex(random_bytes(16));
echo strlen($token), "\n";

Output

Version	Change
PHP 4.0	Added

base64_encode() · Encode binary data or text as Base64, using only letters, digits, + and /, so it travels safely as text.
ord() · Return the value (0 to 255) of the first byte of a string, such as 65 for "A". The reverse of chr().
PHP Strings · tutorial