by Boyma Fahnbulleh <[email protected]>
Handshake is a decentralized, permission-less naming protocol compatible with DNS. We seek to solve Zooko's triangle through the use of a utxo-based blockchain, which manages the registration, renewal, and transfer of DNS top-level domains (TLDs). The initial goal is not to replace the DNS protocol but to replace the root zone file and the root servers with a decentralized, public commons. By tying name ownership to a utxo, and embedding DNS records into its metadata, a chain of trust can be created by a digital signature and verified by querying blockchain data. A decentralized network of validating peers anchors this chain of trust. The ultimate goal is to provide an alternative to existing Certificate Authorities.
Our naming protocol differs from its predecessors in that it has no concept of subdomains at the consensus layer. The protocol also provides secure name resolutions via light client resolvers by committing to name data in the block headers and using compact, merklelized proofs of inclusion and non-inclusion.
We believe this project could be used to add human readability to DIDs by committing to them in the DNS records of names registered on the network. Or the names themselves could exist as DIDs and DID documents could be committed to in the DNS records.
Second-price, blind bid (Vickrey) auctions manage the issuance of names on-chain. A consensus-level covenant system facilitates these auctions by encumbering utxos with spending restrictions. A collection of these covenants model an auction state machine.
For example, to bid on a name, one must spend a utxo in a transaction which creates an output which carries a 'BID' covenant. This output will have a value which is equal to (or higher) than the amount the user intends to bid on the name. It will also include the name up for auction and a commitment to the actual bid amount. The 'BID' covenant will restrict this output from being spent in any transaction that does not create an output with a 'REVEAL' covenant.
The 'REVEAL' covenant essentially reveals the actual bid amount and allows the excess value in the 'BID' covenant to be spent freely. The rest of the auction process, as well as DNS record updates and name transfers, are modeled in this covenant system.
Consensus rules reserve all entries in ICANN's existing root zone file. Names in the list of Alexa top 100,000 domains are also reserved. The latter names are converted to TLDs by selecting their first domain name label. Name owners can bypass the auction system and claim names through the use of DNSSEC ownership proofs. We also have a sunrise period to allow trademark holders without domains in the Alexa top 100,000 to reserve names.
The DNSSEC ownership proofs mentioned above are a stricter subset of DNSSEC proofs. They do not allow for CNAME glue or wildcards, and every label must be separated by a zone cut using a typical DS-to-DNSKEY setup for referrals. All zone referrals are retrieved and combined to produce the final proof.
These proofs must stem from ICANN's key-signing keys (KSKs) to the final ZSK in the target zone. The ultimate zone-signing key (ZSK) must sign a TXT record which commits to the name's desired address on the blockchain. The proof is broadcast to the peer-to-peer network and included by miners in the coinbase transaction of a block. The consensus rules dictate that the miner must create an output for the associated proof, granting the name to the committed address.
hsd is a full node, Javascript implementation of the protocol and an authoritative name resolver for the root zone. hnsd is an SPV name resolver written in C. It acts as a light client to the blockchain, as well as a recursive name server. It can serve provable resource records without having the resource requirements of a full node.
This document is a high-level overview of the Handshake protocol. For a more detailed description of the protocol, please read the project paper.