> For the complete documentation index, see [llms.txt](https://shinkalabs.gitbook.io/hub/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://shinkalabs.gitbook.io/hub/andromeda/reference/glossary.md). # Glossary **Andromeda API.** The single hosted HTTPS surface you call. It runs the engines, the on-chain programs, gas sponsorship, MCP, webhooks and the audit log on your behalf. **Attestor.** An off-chain component that a program trusts to vouch for a signature's validity. Andromeda deliberately has none; see [Zero attestor](/hub/andromeda/concepts/zero-attestor.md). **Challenge.** A fixed 32-byte value a user signs off-chain to authorise an action. Domain-separated: it binds the operation, the dWallet, the nonce and the signer's slot. See [Domain-separated challenges](/hub/andromeda/on-chain-programs/challenges.md). **Curve.** The elliptic curve a dWallet's key lives on: Ed25519, SECP256K1, SECP256R1, or Ristretto. Determines which chains the dWallet can sign for. See [Chains & curves](/hub/andromeda/reference/chains-curves.md). **Custody-free.** Andromeda never holds a complete user private key, and never signs Encrypt transactions. See [Custody-free model](/hub/andromeda/concepts/custody-free.md). **Discovery.** Off-chain proof that a user controls an external wallet, via that wallet's message-signing convention. See [Discovery](/hub/andromeda/guides/discovery.md). **DKG (Distributed Key Generation).** The protocol that creates a dWallet and produces its public key. Run once per wallet. **dWallet.** A wallet whose signing key is split and never assembled in one place; signing is a 2PC-MPC protocol, not a stored secret. See [dWallets & 2PC-MPC](/hub/andromeda/concepts/dwallets.md). **FHE (fully homomorphic encryption).** Computing over data that stays encrypted. Provided by Encrypt. See [Confidential computing (FHE)](/hub/andromeda/concepts/fhe.md). **Gas sponsor.** The keypair Andromeda uses to pay Solana fees and act as fee payer on transactions it assembles for sponsored flows. Never an authority over a dWallet. **Identity layer.** Optional. Derives a dWallet address deterministically from an OAuth provider plus subject (or email, or passkey), so recovery works across clients. See [Identity](/hub/andromeda/concepts/identity.md). **Idempotency key.** A header that makes a retried request replay the original response instead of executing again. See [Idempotency keys](/hub/andromeda/guides/idempotency.md). **MCP (Model Context Protocol).** A standard for agents to call tools. Andromeda exposes every REST route as an MCP tool. See [MCP](/hub/andromeda/concepts/mcp.md). **Member slot.** A canonical 34-byte identifier for a recovery owner: `[scheme byte || identifier || padding]`. Fixed width so on-chain comparisons are unambiguous. See [Recovery schemes](/hub/andromeda/reference/recovery-schemes.md). **NEK (network encryption key).** The public key the Encrypt network uses for a deployment; you encrypt FHE inputs against it. **PDA (program-derived address).** A Solana account address derived from a program and some seeds. Policy accounts and quorum sessions are PDAs; the seeds include an init-authority hash to prevent front-running. **Policy.** A Solana program that holds a dWallet's signing authority and only lets a signature through if its rule is satisfied. Eight templates. See [On-chain policies](/hub/andromeda/concepts/policies.md). **Precompile.** A Solana runtime instruction that verifies a signature (Ed25519, Secp256k1, Secp256r1) directly. Andromeda's programs require a precompile check to pass before acting on a signature. See [Precompile validation](/hub/andromeda/on-chain-programs/precompiles.md). **Prepare / submit.** The two-step pattern for some operations: `prepare` returns an unsigned transaction; you sign it; `submit` broadcasts it. **Presignature.** Expensive precomputation that makes a later signing operation fast. Build a buffer ahead of time. **Quasar.** The framework the eight on-chain policy programs are built with. **Quorum.** An M-of-N set of recovery owners; any M of them together can recover a dWallet. Staged in a PDA so size is unbounded. See [Quorum via PDA staging](/hub/andromeda/on-chain-programs/quorum-staging.md). **Replay nonce.** A monotonic on-chain counter per flow (admin, primary recovery, quorum session) that makes each action single-use. **Re-encrypt share.** Move the user-side key share of a dWallet to a new holder. **Scope.** What an API key may do: `read`, `write`, `admin`, or wildcard. See [Authentication](/hub/andromeda/getting-started/auth.md). **Session key.** A temporary, scoped key over a dWallet with on-chain limits (expiry, uses, amount, destinations). See [Session keys](/hub/andromeda/guides/session-keys.md). **Zero attestor.** The stance that no off-chain component is trusted for signature validity; the chain re-checks every signature. See [Zero attestor](/hub/andromeda/concepts/zero-attestor.md). --- # Agent Instructions This documentation is published with GitBook. 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