How Make Signature

// Import packages for sign
import * as TinySecp256k1 from 'tiny-secp256k1';
import * as encHex from 'crypto-js/enc-hex';
import * as sha256 from 'crypto-js/sha256';
 
// Define a custom function to execute the logic described on the Build Transaction page.
// Each user can implement their own version of this function and use it accordingly
const buildResult = await buildTx();
/* Example of result
 {
  "tx": "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",
  "messages": [
    {
      "type": "cosmos.staking.v1beta1.MsgDelegate",
      "delegatorAddress": "osmo1gr0e3pj3y6fqvzyam0qxyw9h5dwfrvh8zv3x9p",
      "validatorAddress": "osmovaloper1clpqr4nrc4khgkxj78fcwwh6dl3uw4epsluffn",
      "amount": { "denom": "uosmo", "amount": "1" }
    }
  ],
  "fee": { "amount": [{ "denom": "uosmo", "amount": "760" }], "gas": "303815" },
  "publicKey": {
    "@type": "/cosmos.crypto.secp256k1.PubKey",
    "key": "A00Jvfv1luvAODaiOPIMZpDTWSq7qvoFV8k7ptdsDqLU"
  },
  "accountNumber": "63277",
  "sequence": "12"
}
*/
 
// Removes the '0x' string from the beginning of the tx.
const signDoc = buildResult.tx.replace(/^0x(.*)/, '$1');
// SignDoc Example: 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
 
// The part that creates a Buffer using the user's Private Key.
// If the Private Key starts with '0x', the '0x' prefix is removed and the value is used.
const privateKey = Buffer.from(
  'ca7e19f112f2a01aaccefba10840bdcbcc16344c310afff65397eaa940e51f1d',
  'hex',
);
const hashedSignDoc = sha256(encHex.parse(signDoc)).toString(encHex);
const signResult = TinySecp256k1.sign(Buffer.from(hashedSignDoc, 'hex'), privateKey);
 
const signatureHex = Buffer.from(signResult).toString('hex');
 
// Use this to broadcast the transaction
const signature = `0x${signatureHex}`;
// Example: 0x10d0688f545e01802023a12cba8a69be50bd6e504b21781d97e7baaab61c4e8619753e64a377e85bf1488b4cdc34c87ce49c4d0d8fc0b52857129bf5aeccaed5