Let's face it randomness sits at the heart of every game of chance; it decides who wins and who doesn't. It also decides something that might not be obvious but is very important - whether or not the game felt fair or rigged. Throughout history, randomness has been something that we're simply asked to trust. The process has been the same: a button is pressed, a winner appears, and we're told it was "random".

As we know, history hasn't been kind to that model.

Trad lotteries and online draws usually rely on private systems: closed servers, hidden logic, and outcomes that aren't independently verifiable. Players become suspicious, even when no one cheats, because there's no way of verifying that the game was fair. And I think there's one thing we can all agree on; when money is involved, blind trust becomes the weakest link.

On-chain randomness is designed to solve this exact problem - trusting that the game was fair.

At its core, on-chain randomness means that random outcomes are generated by smart contracts, using publicly available and visible blockchain data. The rules are written in publicly accessible logic, the inputs are on-chain, and the result is permanent once recorded. Anyone can inspect the transaction and verify that the result was random, and hence fair.

On-chain randomness removes hidden control. No admin can maliciously redraw winners to favor him, no internal script can "adjust" results after the fact. If anything happens, it happens on the blockchain, where everyone can see it.

But before we get ahead of ourselves, on-chain randomness isn't magic.

No system is completely immune to every theoretical attack, and with different approaches we make different tradeoffs. Some systems prioritize speed, others cost and others cryptographic strength. A huge, high-stakes draw shouldn't use the same randomness model as a low-stakes, everyday lottery.

With that as our north star, we decided to build a few solid randomness systems with specific use cases in mind, instead of chasing a single 'perfect' solution.

One of those is ChainMix. It gathers entropy from multiple on-chain sources, things like previous blockhash, timestamps, gas-related data and an internal nonce, and it hashes them together into a seed which is used to generate random number(s) instantly.

ChainMix is fast, simple and cheap.While we didn't design it to be the most tamper-proof system, it significantly raises the bar, in terms of manipulation difficulty compared to naive approaches like using a single blockhash. We designed it for low-to-mod stakes games, where immediate results matter more than absolute cryptographic guarantees.

We also developed BeaconSpin, which leans more heavily on Ethereum’s native randomness. It combines PREVRANDAO with the immutable hash of the previous block to create an entropy seed, btw all this happens on chain and in a single transaction. Since PREVRANDAO comes from Ethereum’s consensus layer, it offers stronger guarantees than basic block-based randomness while still being pretty lightweight and efficient.

Neither one of these approaches asks you to trust us, and that's the point.

You don't need to understand validator economics or how hashing works to benefit from on-chain randomness. All that matters is that the system is transparent and autonomous. With such systems we can confidently assure players that the games are fair, and the best part is that they don't have to take our word for it, they can verify.

On-chain randomness doesn't fix every problem in games of chance, but it fixes one as old as time: being told to trust a system you can't see.

If this changed how you think about randomness for games of chance, share it. The more people expect randomness to be verifiable, the closer wee get to fairer games of chance.

Let's face it randomness sits at the heart of every game of chance; it decides who wins and who doesn't. It also decides something that might not be obvious but is very important - whether or not the game felt fair or rigged. Throughout history, randomness has been something that we're simply asked to trust. The process has been the same: a button is pressed, a winner appears, and we're told it was "random".

As we know, history hasn't been kind to that model.

Trad lotteries and online draws usually rely on private systems: closed servers, hidden logic, and outcomes that aren't independently verifiable. Players become suspicious, even when no one cheats, because there's no way of verifying that the game was fair. And I think there's one thing we can all agree on; when money is involved, blind trust becomes the weakest link.

On-chain randomness is designed to solve this exact problem - trusting that the game was fair.

At its core, on-chain randomness means that random outcomes are generated by smart contracts, using publicly available and visible blockchain data. The rules are written in publicly accessible logic, the inputs are on-chain, and the result is permanent once recorded. Anyone can inspect the transaction and verify that the result was random, and hence fair.

On-chain randomness removes hidden control. No admin can maliciously redraw winners to favor him, no internal script can "adjust" results after the fact. If anything happens, it happens on the blockchain, where everyone can see it.

But before we get ahead of ourselves, on-chain randomness isn't magic.

No system is completely immune to every theoretical attack, and with different approaches we make different tradeoffs. Some systems prioritize speed, others cost and others cryptographic strength. A huge, high-stakes draw shouldn't use the same randomness model as a low-stakes, everyday lottery.

With that as our north star, we decided to build a few solid randomness systems with specific use cases in mind, instead of chasing a single 'perfect' solution.

One of those is ChainMix. It gathers entropy from multiple on-chain sources, things like previous blockhash, timestamps, gas-related data and an internal nonce, and it hashes them together into a seed which is used to generate random number(s) instantly.

ChainMix is fast, simple and cheap.While we didn't design it to be the most tamper-proof system, it significantly raises the bar, in terms of manipulation difficulty compared to naive approaches like using a single blockhash. We designed it for low-to-mod stakes games, where immediate results matter more than absolute cryptographic guarantees.

We also developed BeaconSpin, which leans more heavily on Ethereum’s native randomness. It combines PREVRANDAO with the immutable hash of the previous block to create an entropy seed, btw all this happens on chain and in a single transaction. Since PREVRANDAO comes from Ethereum’s consensus layer, it offers stronger guarantees than basic block-based randomness while still being pretty lightweight and efficient.

Neither one of these approaches asks you to trust us, and that's the point.

You don't need to understand validator economics or how hashing works to benefit from on-chain randomness. All that matters is that the system is transparent and autonomous. With such systems we can confidently assure players that the games are fair, and the best part is that they don't have to take our word for it, they can verify.

On-chain randomness doesn't fix every problem in games of chance, but it fixes one as old as time: being told to trust a system you can't see.

If this changed how you think about randomness for games of chance, share it. The more people expect randomness to be verifiable, the closer wee get to fairer games of chance.