hash_init
(PHP 5 >= 5.1.2, PECL hash >= 1.1)
hash_init — Initialize 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 以上例程会输出：
<?php
$ctx = hash_init('md5');
hash_update($ctx, 'The quick brown fox ');
hash_update($ctx, 'jumped over the lazy dog.');
echo hash_final($ctx);
?>
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
