Luke Champine

Cool things about the new protocol: * All communication with the host is encrypted. Your files have always been encrypted, of course, but now all metadata (such as the contract ID) is encrypted too.

* The host can provide a Merkle proof for a set of modifications. Previously, when you added or modified contract data, you had to calculate the new Merkle root yourself, but now the host can prove that "old Merkle root + modifications = new Merkle root."

This means that the renter needs hardly any info to upload or download: just the host's public key, the contract ID, and a secret key. That's only 96 bytes -- small enough to fit in a QR code.

* Multi-sector downloads: previously, each download request could only fetch data from a single sector. Now you can fetch any concatenation of bytes within the contract, which greatly reduces latency and allows for nicer IO abstractions.

* Sector metadata: you can now download the metadata of all your contract's sectors from the host. This enables you to implement an entire "filesystem at a distance" on the host, 100% trustlessly. It also lets you periodically challenge the host by requesting a random sector.

I plan to use these new features to implement high-performance FUSE bindings for Sia. Read-only at first, but eventually writable too. A clean and efficient file-like abstraction will make Sia much more approachable for new developers. Exciting times ahead!