# sodium_crypto_generichash_init

(PHP 7 >= 7.2.0, PHP 8)

sodium_crypto_generichash_init — Initialize a hash for streaming

### Descripción

sodium_crypto_generichash_init(string `$key` = "", int `$length` = `SODIUM_CRYPTO_GENERICHASH_BYTES`): string

The initialization method for the streaming generichash API.

### Parámetros

`key`

  The generichash key.

`length`

  The expected output length of the hash function.

### Valores devueltos

Returns a hash state, serialized as a raw binary string.

### Ejemplos

Ejemplo #1 sodium_crypto_generichash_init() example

`<?php
$messages = [random_bytes(32), random_bytes(32), random_bytes(16)];
$state = sodium_crypto_generichash_init('', 32);
foreach ($messages as $message) {
sodium_crypto_generichash_update($state, $message);
}
$final = sodium_crypto_generichash_final($state, 32);
var_dump(sodium_bin2hex($final));
$allAtOnce = sodium_crypto_generichash(implode('', $messages));
var_dump(sodium_bin2hex($allAtOnce));
?>`

El resultado del ejemplo sería algo similar a:

    string(64) "a2939a9163cb7c796ec28e01028489e72475c136b2697ea59e3e760ab4a8ab20"
    string(64) "a2939a9163cb7c796ec28e01028489e72475c136b2697ea59e3e760ab4a8ab20"