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Tasra SDK

Glossary

Slot, k-of-n, MSK, epoch, DKG, DCQL, holder proof, committee — defined.

Every domain term this README uses, defined once.

  • Slot — the unit of key management: one threshold keypair plus the policy governing access to it. Created on-chain, identified by a 32-byte slotId. Everything in this SDK is scoped to a slot.
  • k-of-n — the threshold. A slot’s key is split into n shards across n nodes; any k of them can cooperate to decrypt or sign. Fewer than k can do nothing, and no single node ever holds the whole key.
  • Shard — one node’s share of a slot’s secret key.
  • MSK / master secret key — the whole secret, reconstructed in your process by Lagrange-interpolating k shards. Only the local-decrypt path does this; threshold sign/decrypt never reconstructs it. Session.close() zeroizes it.
  • MPK / group public key — the slot’s public key. Public and served by any node, so encryption needs no credentials.
  • Epoch — the slot’s key generation. Rotation (e.g. after revoking a holder) bumps it; envelopes carry the epoch they were encrypted under so a rotated slot can still read old ciphertext.
  • DKG — distributed key generation. The committee generating a slot’s key among themselves after creation, with no dealer. Takes a moment after createSlot, which is why getting-started.ts polls for a non-empty group key.
  • DCQL — the query language a slot’s access rule is written in, evaluated against a holder’s verifiable credentials. The chain stores only a salted hash of the rule; the clear rule is provisioned to the nodes.
  • Credential / VC — a signed claim about a holder (a verifiable credential), presented to the verifier and evaluated against the DCQL rule.
  • Holder proof — a proof-of-possession signed with the holder DID’s authentication key, binding a presentation to a fresh verifier nonce. Stops a leaked credential from being replayed by someone else.
  • Verifier — the service that checks credentials against a slot’s rule and mints the short-lived JWT the keeper nodes accept.
  • Committee — two distinct things, unfortunately: (1) the keeper committee, the n nodes drawn on-chain to hold a slot’s shards; (2) the verifier committee of the committee path, a per-request quorum drawn from the on-chain verifier set. Where it matters below, which one is meant is stated.
  • TASRA — the network’s token, used for staking, metering, and settlement. (Spelled Tasra in contract and type names.)

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