The new iroh-blobs design restores the initial "one unique identifier for each file" ethos of IPFS (abandonned by IPFS), to reduce swarm fragmentation. It takes the standard Blake3 hashing algorithm to generate file CIDs (equivalent to Bittorrent magnet infohash).

The protocol uses the Mainline Bittorrent DHT (not a custom DHT). There is no notion of block CIDs (no potential deduplication, but also less scalability issues for announcing each block CID on the DHT).

So that's a lot of design simplifications that will improve implementation time.

If you are interested, have a try at Iroh-share, a CLI and TUI Rust implementation.