Signing

This walkthrough covers how to sign Amino transactions, Direct transactions, arbitrary messages, and Cosmos ecological chain data that supports Ethereum signatures through UKey Wallet Cosmos Provider.

---

Amino signature

Amino is suitable for Cosmos transactions that still use traditional encoding:

const chainId = "cosmoshub-4";
const signer = "cosmos1demoaccount...";

const signDoc = {
  chain_id: chainId,
  account_number: "0",
  sequence: "0",
  fee: {
    amount: [{ denom: "uatom", amount: "5000" }],
    gas: "200000",
  },
  msgs: [
    {
      type: "cosmos-sdk/MsgSend",
      value: {
        from_address: signer,
        to_address: "cosmos1demoaccount...",
        amount: [{ denom: "uatom", amount: "1000000" }],
      },
    },
  ],
  memo: "",
};

const callResult = await provider.signAmino(chainId, signer, signDoc);

console.log({
  signed: callResult.signed, // Note: signed document
  signature: callResult.signature, // Example response: { pub_key, signature }
});

---

Direct signature (Protobuf)

Direct signature is suitable for modern Protobuf encoding transactions and is also the more common method for most new accesses:

import { makeSignDoc } from "@cosmjs/proto-signing";

const chainId = "cosmoshub-4";
const signer = "cosmos1demoaccount...";

const signDoc = makeSignDoc(
  bodyBytes, // Note: trading body
  authInfoBytes, // Note: Certification information including handling fee
  chainId,
  accountNumber,
);

const callResult = await provider.signDirect(chainId, signer, signDoc);

console.log({
  signed: callResult.signed,
  signature: callResult.signature,
});

---

Sign arbitrary data

signArbitrary can be used for login authentication or off-chain message verification. Add domain name, nonce and timestamp to the message:

const chainId = "cosmoshub-4";
const signer = "cosmos1demoaccount...";
const data = "MyApp login time：2024-01-01T00:00:00Z";

const signature = await provider.signArbitrary(chainId, signer, data);

// Validate signature
const isValid = await provider.verifyArbitrary(
  chainId,
  signer,
  data,
  signature,
);
console.log("Signature check passed:", isValid);

---

broadcast deal

const chainId = 'cosmoshub-4'
const txBytes = new Uint8Array([...]) // Note: Signed transaction bytes

// Available broadcast modes: 'block', 'sync', 'async'
const callResult = await provider.sendTx(chainId, txBytes, 'sync')

console.log('Tx hash:', callResult)

---

Signed Ethereum data

Some Cosmos ecological chains support Ethereum-style signatures, such as Evmos:

const callResult = await provider.signEthereum(
  chainId,
  signer,
  data, // Note: message to sign
  "message", // allowed values: 'message' | 'transaction'
);

console.log("Generated signature:", callResult);

---

Handle Errors

try {
  await provider.enable("cosmoshub-4");
} catch (error) {
  if (error.code === 4001) {
    console.log("The user declined the request");
  } else if (error.message.includes("not supported")) {
    console.log("That chain is unsupported; try experimentalSuggestChain instead");
  } else {
    console.error("Unable to connect:", error);
  }
}