random_bytes

Function name: random_bytes()

Applicable version: PHP 7.0.0 and above

Function description: The random_bytes() function is used to generate a random byte string of specified length. This function generates random bytes using the cryptographically secure pseudo-random number generator provided by the operating system.

Syntax: random_bytes(int $length): string|false

parameter:

• $length: The length of the generated random byte string, expressed in bytes. Must be a positive integer.

Return value:

• Returns a string containing random bytes, or returns false when the generation fails.

Example:

 // 生成一个包含10个字节的随机字节串$randomBytes = random_bytes(10); // 打印随机字节串的16进制表示echo bin2hex($randomBytes);

The above example outputs a hexadecimal representation of a random byte string similar to the following:

 d6f5389e1b6a85c0c9

Notes:

1. The random_bytes() function relies on the cryptographically secure pseudo-random number generator provided by the operating system. Therefore, the strength of the generated random byte string depends on the quality of the random number generator of the operating system.
2. The generated random byte string may contain any bytes, including control characters and non-print characters. When processing random byte strings, be careful to ensure that there is no security problem or unexpected behavior.
3. On some operating systems, calling of the random_bytes() function may be blocked if there is not enough entropy available to generate random bytes. In this case, consider using the random_int() function to generate a random integer and converting it into a byte string using the pack() function.

Reference documentation: https://www.php.net/manual/en/function.random-bytes.php