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For the first ten years, Dash had only one chain: a Bitcoin-based, proof-of-work, UTXO chain prioritized for payments.

Masternodes provided special services including instant transactions, high security, and privacy, but everything was still done on one layer.
 
With the launch of the Evolution platform this year, Dash now has another chain: a loosely Cosmos-based, proof-of-stake (still run by the same EvoNodes who provide masternode services for the payments chain), account-based chain prioritized for data and decentralized applications.
 
Why maintain two separate chains if it’s essentially the same network, same validators, same currency? 

## 1: Two Different Use Cases

First, the two chains are primed for two very different use cases. Without any advanced privacy functions like zero-knowledge proofs, the UTXO model is inherently more private the account-based model. It also is inherently much easier to scale to high transaction volumes.

Having a dual security model (miners and masternodes) also offers the highest and most robust security and liveness guarantees, which are particularly important for a financial network where people need to have consistent access to their money.
 
The account-based model is able to achieve global state, which is very important for decentralized applications, and necessary for the kind of needs the Evolution platform has. A smaller subset of the network (EvoNodes) also runs Evolution so as to keep decentralized data storage costs lower, and having this on a separate chain from the main payments chain avoids passing that trade-off to users of the monetary network.

And finally, at very high volumes of transactions with large amounts of data, some advanced scaling techniques like sharding may become necessary. These introduce some trade-offs such as latency, and keeping this to the data chain can avoid visiting them on all use cases.
 
## 2: Avoids Disruption

Second, a new chain avoids disruption that would be caused by serious changes to the original chain.

Dash has been building a global ecosystem of decentralized money and payments for the past ten years, and introducing severe changes to the payments chain would disrupt this for users, business partners, developers, and more.
 
## 3: Risk Mitigation

And finally, having two chains can be beneficial for risk mitigation. In the past, sudden spikes in usage for data use cases have disrupted the ability for Bitcoin and Ethereum users to access their money.

With Dash, a suddenly-popular DApp pushing the Platform chain to its limits would have no effect in preventing users of the Core chain to access and user their money as they normally do.
 
We believe that Dash’s two-chain solution, segmented by use case, can provide many benefits without fragmenting the ecosystem as is a risk of popular second-layer scaling approaches.

[Read more about Dash's Evolution upgrade here](https://inleo.io/@dashpay/introducing-dash-evolution).

Posted Using [InLeo Alpha](https://inleo.io/@dashpay/why-does-dash-have-two-separate-blockchains--6ph)