Provably Fair

// Example PHP code to calculate the roll
//
// Assuming you have the server seed, client seed, and nonce

$serverSeed = 'Your server seed here'; // to be generated by the server
$clientSeed = 'Your client seed here'; // can be set by the user
$nonce = 1; // this is a counter that starts at 1 and increments with each case opening

// Hash the server seed to ensure it is not tampered with
$serverHash = hash('sha256', $serverSeed); // hash of the server seed

// Example PHP code to calculate the roll
$hash = hash_hmac('sha512', "{$clientSeed}-{$nonce}", $serverSeed);

// Extracting the first 13 characters of the hash
$hexPart = substr($hash, 0, 13);
$decimal = hexdec($hexPart);

// Convert to a roll between 0.001 and 100.000
$roll = (($decimal % 100000) + 1) / 1000;

// This gives a roll between 0.001 and 100.000

// Your roll
echo "Roll: $roll\n";

// Example with 3 items
Item A: 50% chance (0.000 to 50.000)
Item B: 30% chance (50.001 to 80.000)
Item C: 20% chance (80.001 to 100.000)

// If roll = 75.123
// Item B would be selected (as 50.001 ≤ 75.123 ≤ 80.000)

// Server seed rotation rules

1. Each server seed is used for up to 100 case openings
2. After 100 openings, a new server seed is automatically generated
3. When a server seed is revealed, a new one is generated for future openings
4. Each user has their own server seed that is used across all their openings