zcash_sign_mpc

Instructions

Implementation Reference

• src/tools/sign-mpc.ts:19-57 (handler)

  Handler function for 'zcash_sign_mpc'. Accepts wallet_id, message_hash, chain, encryption_seed, sui_private_key, and optional ika_coin_id. Returns instructions for using the @frontiercompute/zcash-ika package to perform 2PC-MPC signing.

  async ({ wallet_id, message_hash, chain, encryption_seed, sui_private_key, ika_coin_id }) => {
    try {
      const hashAlgo: Record<string, string> = {
        "zcash-transparent": "DoubleSHA256",
        bitcoin: "DoubleSHA256",
        ethereum: "KECCAK256",
      };
  
      const result = {
        status: "sign_requires_zcash_ika_package",
        instructions: {
          step1: "import { sign } from '@frontiercompute/zcash-ika'",
          step2: `const sig = await sign(config, { messageHash: Buffer.from('${message_hash}', 'hex'), walletId: '${wallet_id}', chain: '${chain}', encryptionSeed: '${encryption_seed}' })`,
        },
        signing_params: {
          curve: "secp256k1",
          algorithm: "ECDSA",
          hash: hashAlgo[chain],
        },
        flow: [
          "TX 1: Request presign (pre-compute MPC ephemeral key share)",
          "Poll for presign completion (up to 5 min on testnet)",
          "TX 2: Approve message + request signature",
          "Poll for sign completion",
          "Parse DER-encoded ECDSA signature from output",
        ],
        wallet_id,
        message_hash,
        chain,
      };
  
      return {
        content: [{ type: "text" as const, text: JSON.stringify(result, null, 2) }],
      };
    } catch (err) {
      const msg = err instanceof Error ? err.message : String(err);
      return { content: [{ type: "text" as const, text: `Error: ${msg}` }], isError: true };
    }
  }

• src/tools/sign-mpc.ts:9-17 (schema)

  Input schema/type definitions for the zcash_sign_mpc tool using Zod. Defines wallet_id, message_hash, chain (zcash-transparent|bitcoin|ethereum), encryption_seed, sui_private_key, and optional ika_coin_id.

  {
    wallet_id: z.string().describe("dWallet object ID from create_wallet"),
    message_hash: z.string().describe("Hex-encoded 32-byte message hash (sighash) to sign"),
    chain: z
      .enum(["zcash-transparent", "bitcoin", "ethereum"])
      .describe("Chain determines hash algorithm (DoubleSHA256 or KECCAK256)"),
    encryption_seed: z.string().describe("Hex encryption seed from wallet creation"),
    sui_private_key: z.string().describe("Sui private key for signing the MPC transactions"),
    ika_coin_id: z.string().optional().describe("IKA coin object ID"),

• src/tools/sign-mpc.ts:4-59 (registration)

  Registration of the 'zcash_sign_mpc' tool on the McpServer via the registerSignMpcTool function.

  export function registerSignMpcTool(server: McpServer) {
    server.tool(
      "zcash_sign_mpc",
      "Sign a message hash through Ika 2PC-MPC. Two on-chain transactions: presign + sign. " +
        "Neither party sees the full private key. Returns DER-encoded ECDSA signature.",
      {
        wallet_id: z.string().describe("dWallet object ID from create_wallet"),
        message_hash: z.string().describe("Hex-encoded 32-byte message hash (sighash) to sign"),
        chain: z
          .enum(["zcash-transparent", "bitcoin", "ethereum"])
          .describe("Chain determines hash algorithm (DoubleSHA256 or KECCAK256)"),
        encryption_seed: z.string().describe("Hex encryption seed from wallet creation"),
        sui_private_key: z.string().describe("Sui private key for signing the MPC transactions"),
        ika_coin_id: z.string().optional().describe("IKA coin object ID"),
      },
      async ({ wallet_id, message_hash, chain, encryption_seed, sui_private_key, ika_coin_id }) => {
        try {
          const hashAlgo: Record<string, string> = {
            "zcash-transparent": "DoubleSHA256",
            bitcoin: "DoubleSHA256",
            ethereum: "KECCAK256",
          };
  
          const result = {
            status: "sign_requires_zcash_ika_package",
            instructions: {
              step1: "import { sign } from '@frontiercompute/zcash-ika'",
              step2: `const sig = await sign(config, { messageHash: Buffer.from('${message_hash}', 'hex'), walletId: '${wallet_id}', chain: '${chain}', encryptionSeed: '${encryption_seed}' })`,
            },
            signing_params: {
              curve: "secp256k1",
              algorithm: "ECDSA",
              hash: hashAlgo[chain],
            },
            flow: [
              "TX 1: Request presign (pre-compute MPC ephemeral key share)",
              "Poll for presign completion (up to 5 min on testnet)",
              "TX 2: Approve message + request signature",
              "Poll for sign completion",
              "Parse DER-encoded ECDSA signature from output",
            ],
            wallet_id,
            message_hash,
            chain,
          };
  
          return {
            content: [{ type: "text" as const, text: JSON.stringify(result, null, 2) }],
          };
        } catch (err) {
          const msg = err instanceof Error ? err.message : String(err);
          return { content: [{ type: "text" as const, text: `Error: ${msg}` }], isError: true };
        }
      }
    );
  }

• src/index.ts:24-49 (registration)

  Import and invocation of registerSignMpcTool in the main server entry point.

  import { registerSignMpcTool } from "./tools/sign-mpc.js";
  import { registerShieldTool } from "./tools/shield.js";
  import { registerVerifyEvmTool } from "./tools/verify-evm.js";
  
  const server = new McpServer({
    name: "zcash-mcp",
    version: "1.2.0",
  });
  
  registerBalanceTool(server);
  registerSendTool(server);
  registerMemoTool(server);
  registerAttestTool(server);
  registerVerifyTool(server);
  registerStatsTool(server);
  registerChainTools(server);
  registerAnchorTools(server);
  registerEventTools(server);
  registerInvoiceTool(server);
  registerWatchTool(server);
  registerReceiptTool(server);
  registerIdentityTool(server);
  registerReputationTool(server);
  registerCrosschainTool(server);
  registerCreateWalletTool(server);
  registerSignMpcTool(server);