Random number

# gmp_random_bits

(PHP 5 >= 5.6.3, PHP 7, PHP 8)

gmp_random_bits — Random number

### Description

gmp_random_bits(int `$bits`): GMP

Generate a random number. The number will be between `0` and `2$bits - 1`.

`bits` must greater than 0, and the maximum value is restricted by available memory.

Caution

This function does not generate cryptographically secure values, and must not be used for cryptographic purposes, or purposes that require returned values to be unguessable.

If cryptographically secure randomness is required, the Random\Randomizer may be used with the Random\Engine\Secure engine. For simple use cases, the random_int() and random_bytes() functions provide a convenient and secure API that is backed by the operating system’s CSPRNG.

### Parameters

`bits`

  The number of bits to generate.

### Return Values

A random GMP number.

### Errors/Exceptions

If `bits` is less than `1`, a ValueError will be thrown.

### Examples

Example #1 gmp_random_bits() example

`<?php
$rand1 = gmp_random_bits(3); // random number from 0 to 7
$rand2 = gmp_random_bits(5); // random number from 0 to 31
echo gmp_strval($rand1) . "\n";
echo gmp_strval($rand2) . "\n";
?>`

The above example will output:

    3
    15

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