Php Generate Random Hash Key
(PHP 7 >= 7.1.2)
hash_hkdf — Generate a HKDF key derivation of a supplied key input
This function does not generate cryptographically secure values, and should not be used for cryptographic purposes. If you need a cryptographically secure value, consider using randomint, randombytes, or opensslrandompseudobytes instead. Generate a random number using your favourite random-number generator; Multiply and divide it to get a number matching the number of characters in your code alphabet; Get the item at that index in your code alphabet. Repeat from 1) until you.
Description
$algo
, string$ikm
[, int$length
= 0 [, string$info
= ' [, string$salt
= ' ]]] ) : stringParameters
algo
Name of selected hashing algorithm (i.e. 'sha256', 'sha512', 'haval160,4', etc.) See hash_algos() for a list of supported algorithms.
Note:
Non-cryptographic hash functions are not allowed.
ikm
Input keying material (raw binary). Cannot be empty.
length
Desired output length in bytes. Cannot be greater than 255 times the chosen hash function size.
If length
is 0, the output length will default to the chosen hash function size.
info
Application/context-specific info string.
salt
Salt to use during derivation.
While optional, adding random salt significantly improves the strength of HKDF.
Return Values
Returns a string containing a raw binary representation of the derived key (also known as output keying material - OKM); or FALSE
on failure.
Errors/Exceptions
An E_WARNING
will be raised if ikm
is empty, algo
is unknown/non-cryptographic, length
is less than 0 Adobe master collection cs6 key generator free download. or too large (greater than 255 times the size of the hash function).
Examples
Example #1 hash_hkdf() example
<?php
// Generate a random key, and salt to strengthen it during derivation.
$inputKey = random_bytes(32);
$salt = random_bytes(16);
// Derive a pair of separate keys, using the same input created above.
$encryptionKey = hash_hkdf('sha256', $inputKey, 32, 'aes-256-encryption', $salt);
$authenticationKey = hash_hkdf('sha256', $inputKey, 32, 'sha-256-authentication', $salt);
var_dump($encryptionKey ! $authenticationKey); // bool(true)
?>
The above example produces a pair of separate keys, suitable for creation of an encrypt-then-HMAC construct, using AES-256 and SHA-256 for encryption and authentication respectively.
See Also
- hash_pbkdf2() - Generate a PBKDF2 key derivation of a supplied password
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- Hash Functions