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DynamicSDK.instance.bitcoin.signMessage produces a signature for an arbitrary message using the connected Bitcoin wallet. The default signing protocol is ecdsa; pass protocol: 'bip322-simple' for BIP-322 sign-in flows.

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Basic usage

import 'package:dynamic_sdk/dynamic_sdk.dart';

final sdk = DynamicSDK.instance;
final wallet = sdk.wallets.userWallets.firstWhere(
  (w) => w.chain == 'BTC',
);

final signature = await sdk.bitcoin.signMessage(
  walletId: wallet.id,
  message: 'Hello, Bitcoin!',
);
print('Signature: $signature');

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With protocol and address type

Override the defaults when you need a BIP-322 signature or want to sign with the ordinals address rather than the payment address: 
final signature = await sdk.bitcoin.signMessage(
  walletId: wallet.id,
  message: 'Hello, Bitcoin!',
  protocol: 'bip322-simple', // or 'ecdsa'
  addressType: 'payment',    // or 'ordinals'
);

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Parameters

ParameterTypeDescription
walletIdStringThe id of a wallet whose chain == 'BTC'.
messageStringThe message to sign.
protocolString?Signing protocol: ecdsa (default) or bip322-simple.
addressTypeString?Address type to sign with: payment or ordinals.

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Returns

Future<String> — the signature as a string. The encoding depends on the chosen protocol.
Last modified on May 12, 2026