This is the code that puts a post-quantum validator certificate under the block
hash. It is the thing this project exists to do, and it is published so that the
claim can be checked rather than believed.
What it is. In QBFT the block hash is computed over a re-encoding of the decoded
extraData with the seals removed, so anything the decoder does not know about is
dropped before hashing. Appending a certificate as a new element gives you a
certificate that is stored, gossiped, and entirely absent from the hash. The
design that works instead puts a 32-byte digest of the certificate into
vanityData, which is already under keccak. anchor/README.md sets out the four
designs that died before this one and why.
Scope, stated in the README and repeated here because it matters: consensus on
chain 2800 is classical secp256k1 ECDSA. This binds a post-quantum certificate to
the block hash. It does not make consensus post-quantum and is never described as
such.
What is here: the anchor, the validation rules, the wiring, and the tests,
including the negative controls. Applied to upstream d2032017bb, the pinned base
named in anchor/BASE.txt. One build file changes, by one line, and the README says
which and why. No cryptography is implemented here; Falcon verification calls
Bouncy Castle.
What is not here: no keys, no fleet configuration, and nothing about what is armed
on any running network.
Measured before publishing, on upstream d2032017bb with this overlay applied:
consensus:common and consensus:qbft, 605 tests, 0 failures, identical to the same
tree before this work, class by class.
Three things were found while preparing it, and all three are fixed here:
- the code spoke Romanian in 134 comment lines and 43 strings, 37 of them on
production paths, which is to say in the messages a node prints when it refuses
to start. An auditor given the code to check the guards could not read the
guards.
- ten test classes carried internal issue numbers in their names. They now say
what they test.
- the suite was green partly by ordering luck. One class cleared its system
properties but not the configuration PqAnchorProducer remembers, so it left the
anchor armed for whichever class ran next. Renaming the classes changed the
order and four tests began failing on a guard that was firing correctly. Fixed
where it leaks, with the negative control measured: remove the line and the
pair goes red, restore it and it goes green.
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