Ponos Technology

Why I really like Miden's Guardian approach: it simultaneously strikes the right balance on multiple dimensions

This one is packed! The velocity at which we ship things is honestly incredible. Each bullet point here probably warrants a separate blog post (and some should be full-blown papers) - we'll get to these in time. For now, one more such release, and then mainnet 🚀

We've been working on this for some time, and I'm really excited to finally start sharing the details publicly. In many ways, this is the missing piece for crypto adoption as it provides answers to several critical questions simultaneously: 1. This makes crypto safe and accessible for 99% of people w/o compromising its core value prop. The "not your keys, not your coins" is just too risky for most people, but the alternative, up to now, has been to give up control of your coins to a third party. The Guardian introduces a new point on the spectrum where users retain custody but get the same guardrails as in the traditional financial system (e.g., account balances are fully private, a stolen key does not mean loss of life savings etc.). 2. This provides a clear way to resolve privacy vs. compliance tension. Guardians provide a powerful way to enforce any ruleset on a subset of the users. In many ways, it is like creating a set of economic zones with different compliance rules and different privacy guarantees. For example, we could have a Guardian that manages accounts only for US-based users and are able to impose the required compliance rules that are specific to the US. 3. Importantly, Guardians do not fragment the liquidity of the chain – all accounts managed by Guardians still live on the base chain. This again, is a different point on the spectrum between deploying smart contracts or app chains. Users/institutions don’t want to run a separate chain for every single application – and Guardians provides a way to deploy an application that plugs in directly into the liquidity of the base chain but scales independently. This is made possible by Miden’s architecture of local state and local transaction execution. The above is just scratching the surface – there are many more interesting properties and benefits that Guardians unlock and we’ll share these over the coming weeks. We think of Guardians as a new category of network participants. They are kind of like validators but instead of helping with the consensus, Guardians help secure the network in different ways.

There are 3 ways to put state onchain: 1. Cleartext. 2. Encrypted. 3. State commitments. Cleartext is what almost all chains do today. The state is fully transparent and visible to everyone - but it is also very useful for shared state (especially among a large number of participants). Encrypted state is what most privacy chains do today. The state is onchain but only those with viewing keys can see it. State commitments is when we put only hashes of the state onchain. This makes the state fully private and has a couple of other benefits: - Even if the encryption keys are compromised (or leak somehow) the state still remain fully private. - Harvest now / decrypt later attacks are not possible (because it is impossible to drive the full state form its hash). - This greatly reduces state bloat issues because regardless of the underlying state size, each commitment contributes only ~32 bytes to onchain data.

In "A Peer-to-Peer Electronic Cash System" - the "cash" part is important in more ways than one. Our goal with Miden is to make it work much more like cash.