🎲 Verifiable Randomness: Provably Fair RNG

Learn how Chainlink VRF and VDFs ensure tamper-proof randomness

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Introduction

What is Verifiable Randomness?

**Verifiable randomness** is cryptographically provable random number generation for blockchain applications. Unlike traditional RNG, verifiable randomness provides a proof that numbers were generated fairly without manipulation—critical for gaming, lotteries, NFT minting, and validator selection.

The challenge: blockchains are deterministic by design. Every node must compute the same result. True randomness breaks consensus. Solutions like VRF (Verifiable Random Functions) and VDF (Verifiable Delay Functions) enable provably fair randomness on-chain.

🎲 Why Verifiable Randomness Matters

Gaming & Lotteries

$1B+ blockchain gaming market requires provably fair outcomes

NFT Minting

Random trait assignment and fair launch mechanics (Azuki, Moonbirds)

Validator Selection

Ethereum beacon chain uses RANDAO for unbiased validator rotation

Security Protocols

Sampling, sharding, and consensus mechanisms need unpredictable randomness

Interactive: Randomness Method Comparison

Compare different approaches to generating random numbers on blockchain and understand their security tradeoffs.

Block Hash

Use block.prevrandao (formerly blockhash)

Security

Low

Cost

Free

Latency

Instant

Manipulable

Yes

Primary Risk

Miners can manipulate by withholding blocks

Test Random Generation

Note: This is a demo using JavaScript Math.random() - not blockchain VRF

The Determinism Problem

❌ Why blockhash() fails

Miners can see the block hash before committing and withhold blocks with unfavorable outcomes.

Attack: Miner discards block if random outcome doesn't favor them

⚠️ Why oracles are risky

Centralized oracles can be compromised, censored, or go offline. Single point of failure.

Risk: Trust assumption violates decentralization

✓ Why VRF/VDF work

Cryptographic proofs ensure randomness cannot be predicted or manipulated before commitment.

Solution: Mathematical guarantees replace trust

🎯 Real-World Usage

Chainlink VRF