How can PHP developers securely store and retrieve user-specific data, such as referral codes, to ensure accurate tracking and attribution?

To securely store and retrieve user-specific data like referral codes in PHP, developers can use sessions to track user information across requests. By storing the data in session variables, it ensures that only the user who owns the data can access it, providing a level of security and accuracy in tracking and attribution.

// Start the session
session_start();

// Store user-specific data like referral code
$_SESSION['referral_code'] = 'ABC123';

// Retrieve the referral code
$referral_code = $_SESSION['referral_code'];

// Use the referral code for tracking and attribution
echo "Referral code: " . $referral_code;