PHP5中文手册·Initialize an incremental hashing context -- 追寻梦想＞编程乐园＞PHP 编程

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

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.

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);
?>

上例将输出：

5c6ffbdd40d9556b73a21e63c3e0e904


	PHP5中文手册 hash_hmac hash_update_file hash PHP Manual hash_init (PHP 5 >= 5.1.2, PECL hash:1.1-1.5) hash_init — Initialize an incremental hashing context 说明 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 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); ?>` 上例将输出： 5c6ffbdd40d9556b73a21e63c3e0e904 参见 hash() hash_file() hash_hmac() hash_hmac_file() hash_hmac hash_update_file hash PHP Manual

hash_init