hash_init

Initialize an incremental hashing context ()
resource hash_init ( string algo [, int options, string key] )

参数

algo

Name of selected hashing algorithm (i.e. "md5", "sha256", "haval160,4", etc..)

options

Optional settings for hash generation, currently supports only one option: HASH_HMAC. When specified, the key must be specified.

key

When HASH_HMAC is specified for options, a shared secret key to be used with the HMAC hashing method must be supplied in this parameter.

返回值

Returns a Hashing Context resource for use with hash_update(), hash_update_stream(), hash_update_file(), and hash_final().

范例

例 749. Incremental hashing example

<?php
$ctx
= hash_init('md5');
hash_update($ctx, 'The quick brown fox ');
hash_update($ctx, 'jumped over the lazy dog.');
echo
hash_final($ctx);
?>

上例将输出:

5c6ffbdd40d9556b73a21e63c3e0e904