Curves & chains

The SDK's sign() does not take a "chain" string. It takes a curve, a signature algorithm, a hash, and a message. Chain compatibility is the question of which (curve, algorithm, hash) triple your chain expects.

Curves

import { Curve } from "@mpckit/sdk";

Curve.SECP256K1; // 0
Curve.SECP256R1; // 1
Curve.ED25519;   // 2
Curve.RISTRETTO; // 3

onboard() is parameterized by curve: a SECP256K1 dWallet signs the SECP256K1 family of chains; an ED25519 dWallet signs the ED25519 family. You'll typically have one dWallet per curve per user.

Mapping curve → chains

The chain you broadcast to determines how you encode the signature (recoverable v-byte for EVM, Schnorr for Bitcoin Taproot, raw 64-byte EdDSA for Solana, etc.). The signature bytes the SDK returns are the same regardless.

Signature algorithms and hashes

import { Hash, SignatureAlgorithm } from "@mpckit/sdk";

SignatureAlgorithm.ECDSASecp256k1;     // SECP256K1
SignatureAlgorithm.Taproot;            // SECP256K1 (Bitcoin Taproot)
SignatureAlgorithm.ECDSASecp256r1;     // SECP256R1
SignatureAlgorithm.EdDSA;              // ED25519
SignatureAlgorithm.SchnorrkelSubstrate; // RISTRETTO

Hash.KECCAK256;     // SECP256K1 + ECDSA (Ethereum)
Hash.SHA256;        // SECP256K1 + ECDSA (Bitcoin SegWit), SECP256K1 + Taproot, SECP256R1 + ECDSA
Hash.DoubleSHA256;  // SECP256K1 + ECDSA (Bitcoin legacy)
Hash.SHA512;        // ED25519 + EdDSA
Hash.Merlin;        // RISTRETTO + Schnorrkel

Common combinations:

The hash is part of the algorithm, not a "pre-hash this then sign raw" toggle. Pass the message you want signed; the SDK handles the hashing per the algorithm spec.

Pricing

Pricing is per-op in microUSD (1 microUSD = $0.000001). Op prices ship with the live pricing payload.

const pricing = await api.billingPricing();

pricing.unit;        // "microUSD"
pricing.microPerUsd; // 1_000_000
pricing.ops;         // Record<string, number>: microUSD per op
pricing.opsUsd;      // Record<string, string>: same prices as USD strings

pricing.ops keys are the ops the backend charges for. At time of writing: encryption-key, dwallet.dkg, and sign, with default rates of 1,000 / 50,000 / 10,000 microUSD. Operators can change those defaults, so always read the live values from pricing.ops instead of hardcoding.

pricing.acceptedCoinTypes lists the Sui coin types the backend accepts for deposits, and pricing.coinPricesUsd is the live USD/coin feed used to credit incoming deposits.