# Util (abstract)

**Namespace**: `\ParagonIE\Halite`

## Static Methods

### `hash()`

> `public static` hash(`string $input`, `int $length = 32`): `string`

User-friendly wrapper for `sodium_crypto_generichash`.

Returns a hexadecimal-encoded hash of an input, for any length.

### `keyed_hash()`

> `public static` hash(`string $input`, `string $key`, `int $length = 32`): `string`

User-friendly wrapper for `sodium_crypto_generichash`.

Returns a hexadecimal-encoded keyed hash of an input, for any length.

### `raw_hash()`

> `public static` rawhash(`string $input`, `int $length = 32`): `string`

User-friendly wrapper for `sodium_crypto_generichash`.

Returns a raw binary hash of an input, for any length.

### `raw_keyed_hash()`

> `public static` hash(`string $input`, `string $key`, `int $length = 32`): `string`

User-friendly wrapper for `sodium_crypto_generichash`.

Returns a raw binary keyed hash of an input, for any length.

### `hkdfBlake2b()`

> `public static` hkdfBlake2b(`string $ikm`, `int $length`, `string $info = ''`, `string $salt = null`): `int`

This is a variant of HKDF-HMAC (RFC 5869). Instead of HMAC, it uses a keyed hash
function (BLAKE2b) for key splitting.

### `safeStrcpy()`

> `public static` safeStrcpy(`string $str`): `string`

Returns a copy of a string without triggering PHP's optimizations. The
string returned by this method can safely be used with `sodium_memzero()`
without corrupting other copies of the same string.

### `xorStrings()`

> `public static` xorStrings(`string $left`, `string $right`): `string`

Calculate A xor B, given two binary strings of the same length.

Uses pack() and unpack() to avoid cache-timing leaks caused by chr().