randSeed

Seed the pseudorandom number generator with cryptographically secure randomness.

import { randSeed, IDL, update } from 'azle';

export default class {
    @update([], IDL.Vec(IDL.Nat8))
    generateRandomBytes(): Uint8Array {
        // Seed with secure randomness from the IC
        randSeed();

        // Generate random bytes using standard Math.random()
        const bytes = new Uint8Array(32);
        for (let i = 0; i < bytes.length; i++) {
            bytes[i] = Math.floor(Math.random() * 256);
        }

        return bytes;
    }

    @update([], IDL.Nat)
    rollDice(): number {
        randSeed();
        return Math.floor(Math.random() * 6) + 1;
    }

    @update([IDL.Vec(IDL.Text)], IDL.Text)
    selectRandom(items: string[]): string {
        if (items.length === 0) {
            throw new Error('Cannot select from empty array');
        }

        randSeed();
        const index = Math.floor(Math.random() * items.length);
        return items[index];
    }
}

The randSeed function seeds JavaScript's Math.random() with cryptographically secure randomness from the Internet Computer. This ensures that random number generation is truly unpredictable.

Returns: void

Use Cases:

• Secure random number generation
• Lottery and gaming systems
• Random selection algorithms
• Cryptographic nonce generation

Important Notes:

• Provides cryptographically secure randomness
• Must be called before using Math.random() for security
• Randomness is consensus-based across all replicas
• Call once per method that needs randomness