hash_init Initialize an incremental hashing context


hash_init

(PHP 5 >= 5.1.2, PECL hash >= 1.1)

hash_initInitialize an incremental hashing context

说明

resource hash_init ( string $algo [, int $options = 0 [, string $key = NULL ]] )

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

Example #1 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);
?>

以上例程会输出:

5c6ffbdd40d9556b73a21e63c3e0e904

参见

  • hash() - Generate a hash value (message digest)
  • hash_file() - Generate a hash value using the contents of a given file
  • hash_hmac() - Generate a keyed hash value using the HMAC method
  • hash_hmac_file() - Generate a keyed hash value using the HMAC method and the contents of a given file


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» hash_update
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