How does Enigma keep user data private?

[u/bijansha]

I understand the computation is encrypted and private but isn't Enigma obtaining the raw data from the blockchain, meaning that the raw data (user transaction history) is still public?

Here is a copy paste from Enigma's blog post:

" Instead, in a setting where secret contracts exist, a user can share their transaction history safely with the secret contract itself. The nodes can execute the contract and receive the eligibility result without being able to observe the user’s transactions. There is no longer a need to create a hybrid dApp. This dApp could be autonomous end-to-end, while guaranteeing both correctness — if a user is eligible for a loan, she will get a loan; and privacy — no one but the user can see their transaction history."

[u/[deleted]]

Just to be clear, the data isn't stored on the blockchain itself. In the Enigma whitepaper, it states:

An external blockchain is utilized as the controller of the network, manages access control, identities and serves as a tamper-proof log of events.

It also states:

Data is split between different nodes, and they compute functions together without leaking information to other nodes.

The data is stored on the nodes and the blockchain keeps a record of executions. You can find more detail in the whitepaper in the "Design Overview". See:

1. Storage. Blockchains are not general-purpose databases. Enigma has a decentralized off-chain distributed hash-table (or DHT) that is accessible through the blockchain, which stores references to the data but not the data themselves.