PHP 5 >= 5.1.2, PHP 7, PHP 8, PECL hash >= 1.1
hash_init - Initialize an incremental hashing context
Code Examples

hash_init( string$algo, [int$flags = 0], [string$key = ""], [array$options = []] ): HashContext



Name of selected hashing algorithm (i.e. "md5", "sha256", "haval160,4", etc..). For a list of supported algorithms see hash_algos.


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


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


An array of options for the various hashing algorithms. Currently, only the "seed" parameter is supported by the MurmurHash variants.

Return Values

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


Version Description
8.1.0 The options parameter has been added.
7.2.0 Usage of non-cryptographic hash functions (adler32, crc32, crc32b, fnv132, fnv1a32, fnv164, fnv1a64, joaat) with HASH_HMAC was disabled.
7.2.0 Return HashContext instead of resource.

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Function hash_init:

HASH Message Digest Framework Functions

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