Hash

Hash has several meanings:

• PHP extension
• PHP function
• A general computer science concept, that transforms data into another value
• A general computer science concept, that turns a string into another fixed-sized string, in a way that is difficult to revert. It is also called a digest.
• A synonym for arrays with arbitrary keys, also known as a hashmap, map or associative array
• A character to start a one line comment: #

Hash allows direct or incremental processing of arbitrary length messages using a variety of hashing algorithms.

While the extension hash only processes hashes, there are other extensions which offer these features: openssl, sodium and password hashing. Mhash and mcrypt are older PHP extensions, which are now discontinued.

<?php

    echo hash('ripemd160', 'The quick brown fox jumped over the lazy dog.');
    // produces ec457d0a974c48d5685a7efa03d137dc8bbde7e3
    
    // a conversion table is a hash
    $c = 2;
    $dictionary = [1 => 'a', 2 => 'b', 3 => 'c'];
    echo $dictionary[$c]; 
    
    // This is a hashmap, or also called a hash
    $hashMap = ['name' => 'Henry', 
                'family' => 'Troyat', 
                'age' => 33,
                ];
    
?>

Documentation

See Also

• Numeric hash (nhash) in PHP

Related

• hash() Function
• Cryptographic Hash
• Collection
• Array, []
• Map
• Array Element
• Convert
• Magic Hash
• Secure Hash Algorithm (SHA)
• Hash #
• Argon2
• Automatic Index
• Dictionary
• Data Structure
• Pound #
• array_column
• Cyclic Redundancy Check 32-bit (CRC32)
• HMAC
• Password API
• Bucket
• Hash Comparisons
• Single Sign On (SSO)
• Hash Table
• Hashing
• Message Digest
• Pseudonymisation