Oihana PHP

hexDecode.php

Table of Contents

Functions

hexDecode()  : string|false
Decodes a hexadecimal string into raw bytes.

Functions

hexDecode()

Decodes a hexadecimal string into raw bytes.

hexDecode(string $value) : string|false

Strict, warning-free counterpart of hex2bin() :

  • Accepts both lowercase and uppercase digits ([0-9a-fA-F]).
  • Requires an even number of characters ; an odd length yields false.
  • Rejects any character outside the hex alphabet (including whitespace and non-ASCII bytes) with false instead of PHP's native warning.
  • The empty string decodes to the empty string.

The function does not raise exceptions ; it returns false on any invalid input, mirroring the contract of base64UrlDecode().

Note: when comparing a decoded value to a known secret (e.g. an HMAC tag), always use hash_equals() for constant-time comparison.

Parameters
$value : string

The hexadecimal string to decode. May be empty.

Tags
example 
use function oihana\core\encoding\hexDecode;

echo hexDecode( '616263' ) ;          // "abc"
echo hexDecode( '00FF'   ) ;          // "\x00\xFF" (uppercase accepted)
echo hexDecode( ''       ) ;          // ""

var_dump( hexDecode( '6'      ) ) ;   // bool(false) — odd length
var_dump( hexDecode( '6Z'     ) ) ;   // bool(false) — invalid char
var_dump( hexDecode( '61 62'  ) ) ;   // bool(false) — whitespace forbidden
see
hexEncode()

For the inverse operation.

author

Marc Alcaraz (ekameleon)

since
1.0.8
Return values
string|false —

The decoded raw bytes, or false if $value is not a valid hexadecimal string of even length.

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