Is a session ID in PHP essentially a hash value, or is it a different concept altogether?

A session ID in PHP is not necessarily a hash value, but it is a unique identifier assigned to each session to track user interactions. It can be generated using various methods, including hashing algorithms, but it is not limited to just hash values. To ensure a secure and unique session ID, it is recommended to use a combination of random generation and hashing techniques.

// Generate a secure session ID using random_bytes() and sha1()
$session_id = sha1(random_bytes(16));