feat: add external signer support for ECDSA and EdDSA TSS key generation

modules/sdk-core/src/bitgo/utils/tss/ecdsa/ecdsaMPCv2.ts

@@ -58,6 +58,7 @@ import { envRequiresBitgoPubGpgKeyConfig, isBitgoMpcPubKey } from '../../../tss/
 import { InvalidTransactionError } from '../../../errors';
 import { BitGoBase } from '../../../bitgoBase';
 import { resolveEffectiveTxParams } from '../recipientUtils';
+import type { EcdsaMPCv2KeyGenCallbacks } from '../../../wallet/iWallets';
 
 export class EcdsaMPCv2Utils extends BaseEcdsaUtils {
   private static readonly DKLS23_SIGNING_USER_GPG_KEY = 'DKLS23_SIGNING_USER_GPG_KEY';
@@ -647,6 +648,92 @@ export class EcdsaMPCv2Utils extends BaseEcdsaUtils {
   }
   // #endregion
 
+  /**
+   * Creates ECDSA MPCv2 keychains using external signer callbacks instead of a passphrase.
+   * The external signer holds all private key material; the SDK only coordinates the DKG protocol.
+   */
+  async createKeychainsWithExternalSigner(params: {
+    enterprise: string;
+    callbacks: EcdsaMPCv2KeyGenCallbacks;
+  }): Promise<KeychainsTriplet> {
+    const { enterprise, callbacks } = params;
+    const { mpcv2PublicKey } = await this.getBitgoGpgPubkeyBasedOnFeatureFlags(enterprise, true);
+    const mpcv2Key = mpcv2PublicKey ?? this.bitgoMPCv2PublicGpgKey;
+    assert(mpcv2Key, 'Failed to get BitGo MPCv2 GPG public key');
+    const bitgoPublicGpgKey = mpcv2Key.armor();
+
+    if (envRequiresBitgoPubGpgKeyConfig(this.bitgo.getEnv())) {
+      assert(isBitgoMpcPubKey(bitgoPublicGpgKey, 'mpcv2'), 'Invalid BitGo GPG public key');
+    }
+
+    // Round 1: external signer generates GPG keys and initial DKG messages
+    const { userGpgPublicKey, backupGpgPublicKey, round1Messages, userState, backupState } =
+      await callbacks.initializeCallback({
+        enterprise,
+        bitgoPublicGpgKey,
+      });
+
+    const { sessionId, bitgoMsg1, bitgoToUserMsg2, bitgoToBackupMsg2 } = await this.sendKeyGenerationRound1(
+      enterprise,
+      userGpgPublicKey,
+      backupGpgPublicKey,
+      round1Messages
+    );
+
+    // Round 2: external signer processes BitGo's round 1 response
+    const {
+      round2Messages,
+      userState: userStateAfter2,
+      backupState: backupStateAfter2,
+    } = await callbacks.round2Callback({
+      sessionId,
+      bitgoMsg1,
+      bitgoToUserMsg2,
+      bitgoToBackupMsg2,
+      userState,
+      backupState,
+    });
+
+    const round2Response = await this.sendKeyGenerationRound2(enterprise, sessionId, round2Messages);
+    assert.strictEqual(round2Response.sessionId, sessionId, 'Session ID mismatch after round 2');
+
+    // Round 3: external signer processes BitGo's round 2 response
+    const {
+      round3Messages,
+      userState: userStateAfter3,
+      backupState: backupStateAfter3,
+    } = await callbacks.round3Callback({
+      sessionId,
+      bitgoCommitment2: round2Response.bitgoCommitment2,
+      bitgoToUserMsg3: round2Response.bitgoToUserMsg3,
+      bitgoToBackupMsg3: round2Response.bitgoToBackupMsg3,
+      userState: userStateAfter2,
+      backupState: backupStateAfter2,
+    });
+
+    const round3Response = await this.sendKeyGenerationRound3(enterprise, sessionId, round3Messages);
+    assert.strictEqual(round3Response.sessionId, sessionId, 'Session ID mismatch after round 3');
+
+    // Finalize: external signer verifies BitGo's final message against the derived common keychain
+    const { commonKeychain } = await callbacks.finalizeCallback({
+      sessionId,
+      bitgoMsg4: round3Response.bitgoMsg4,
+      bitgoCommonKeychain: round3Response.commonKeychain,
+      userState: userStateAfter3,
+      backupState: backupStateAfter3,
+    });
+    assert.strictEqual(commonKeychain, round3Response.commonKeychain, 'Common keychains do not match');
+
+    const keychains = this.baseCoin.keychains();
+    const [userKeychain, backupKeychain, bitgoKeychain] = await Promise.all([
+      keychains.add({ source: 'user', keyType: 'tss', commonKeychain, isMPCv2: true }),
+      keychains.add({ source: 'backup', keyType: 'tss', commonKeychain, isMPCv2: true }),
+      this.addBitgoKeychain(commonKeychain),
+    ]);
+
+    return { userKeychain, backupKeychain, bitgoKeychain };
+  }
+
   async sendKeyGenerationRound1(
     enterprise: string,
     userGpgPublicKey: string,

modules/sdk-core/src/bitgo/utils/tss/eddsa/eddsa.ts

@@ -44,9 +44,10 @@ import { KeychainsTriplet } from '../../../baseCoin';
 import { exchangeEddsaCommitments } from '../../../tss/common';
 import { Ed25519Bip32HdTree } from '@bitgo/sdk-lib-mpc';
 import { EncryptionVersion, IRequestTracer } from '../../../../api';
-import { getBitgoMpcGpgPubKey } from '../../../tss/bitgoPubKeys';
+import { envRequiresBitgoPubGpgKeyConfig, getBitgoMpcGpgPubKey, isBitgoMpcPubKey } from '../../../tss/bitgoPubKeys';
 import { EnvironmentName } from '../../../environments';
 import { readKey } from 'openpgp';
+import type { EddsaKeyGenCallbacks } from '../../../wallet/iWallets';
 
 /**
  * Utility functions for TSS work flows.
@@ -438,6 +439,86 @@ export class EddsaUtils extends baseTSSUtils<KeyShare> {
     }
   }
 
+  /**
+   * Creates EdDSA TSS keychains using external signer callbacks instead of a passphrase.
+   * The external signer holds all private key material and pre-encrypts shares to BitGo's GPG key.
+   */
+  async createKeychainsWithExternalSigner(params: {
+    enterprise: string;
+    callbacks: EddsaKeyGenCallbacks;
+  }): Promise<KeychainsTriplet> {
+    const { enterprise, callbacks } = params;
+    const bitgoGpgPubKey = (await getBitgoGpgPubKey(this.bitgo)).mpcV1;
+
+    if (envRequiresBitgoPubGpgKeyConfig(this.bitgo.getEnv())) {
+      assert(isBitgoMpcPubKey(bitgoGpgPubKey.armor(), 'mpcv1'), 'Invalid BitGo GPG public key');
+    }
+
+    const {
+      userGpgPublicKey,
+      backupGpgPublicKey,
+      userToBitgoKeyShare,
+      backupToBitgoKeyShare,
+      userState,
+      backupState,
+      backupCounterPartyKeyShare,
+    } = await callbacks.initializeCallback({ enterprise, bitgoPublicGpgKey: bitgoGpgPubKey.armor() });
+
+    // Create BitGo keychain with pre-encrypted shares from the external signer
+    const bitgoKeychain = await this.baseCoin.keychains().add({
+      keyType: 'tss',
+      source: 'bitgo',
+      keyShares: [
+        { from: 'user', to: 'bitgo', ...userToBitgoKeyShare },
+        { from: 'backup', to: 'bitgo', ...backupToBitgoKeyShare },
+      ],
+      userGPGPublicKey: userGpgPublicKey,
+      backupGPGPublicKey: backupGpgPublicKey,
+      enterprise,
+    });
+
+    // Finalize runs sequentially: user finalize produces a counterparty key share that backup finalize consumes.
+    const coin = this.baseCoin.getChain();
+    const userResult = await callbacks.finalizeCallback({
+      source: 'user',
+      coin,
+      bitgoKeychain,
+      counterPartyGPGKey: backupGpgPublicKey,
+      counterPartyKeyShare: backupCounterPartyKeyShare,
+      state: userState,
+    });
+    assert(userResult.counterpartyKeyShare, 'User finalize did not produce a counterparty key share');
+
+    const backupResult = await callbacks.finalizeCallback({
+      source: 'backup',
+      coin,
+      bitgoKeychain,
+      counterPartyGPGKey: userGpgPublicKey,
+      counterPartyKeyShare: userResult.counterpartyKeyShare,
+      state: backupState,
+    });
+
+    assert(bitgoKeychain.commonKeychain, 'BitGo keychain missing commonKeychain');
+    assert.strictEqual(
+      userResult.commonKeychain,
+      bitgoKeychain.commonKeychain,
+      'User common keychain does not match BitGo'
+    );
+    assert.strictEqual(
+      backupResult.commonKeychain,
+      bitgoKeychain.commonKeychain,
+      'Backup common keychain does not match BitGo'
+    );
+
+    const { commonKeychain } = bitgoKeychain;
+    const [userKeychain, backupKeychain] = await Promise.all([
+      this.baseCoin.keychains().add({ source: 'user', keyType: 'tss', commonKeychain }),
+      this.baseCoin.keychains().add({ source: 'backup', keyType: 'tss', commonKeychain }),
+    ]);
+
+    return { userKeychain, backupKeychain, bitgoKeychain };
+  }
+
   async createCommitmentShareFromTxRequest(params: {
     txRequest: TxRequest;
     prv: string;

modules/sdk-core/src/bitgo/wallet/iWallets.ts

@@ -1,8 +1,10 @@
 import * as t from 'io-ts';
+import { DklsTypes } from '@bitgo/sdk-lib-mpc';
+import { MPCv2BroadcastMessage, MPCv2P2PMessage } from '@bitgo/public-types';
 
 import { EncryptionVersion, IRequestTracer } from '../../api';
 import { KeychainsTriplet, LightningKeychainsTriplet } from '../baseCoin';
-import { Keychain, WebauthnInfo } from '../keychain';
+import { ApiKeyShare, Keychain, WebauthnInfo } from '../keychain';
 import { IWallet, PaginationOptions, WalletShare } from './iWallet';
 import { Wallet } from './wallet';
 
@@ -76,6 +78,105 @@ export interface CreateKeychainCallbackResult {
 
 export type CreateKeychainCallback = (params: CreateKeychainCallbackParams) => Promise<CreateKeychainCallbackResult>;
 
+/** Per-source encrypted session state threaded through MPC rounds by the external signer. */
+export interface ExternalSignerMpcState {
+  encryptedData: string;
+  encryptedDataKey: string;
+}
+
+/** A key share supplied by the external signer — routing fields (from/to) are added by the SDK. */
+export type ExternalSignerKeyShare = Omit<ApiKeyShare, 'from' | 'to'> & {
+  privateShareProof: string;
+  vssProof: string;
+  gpgKey: string;
+};
+
+export type EcdsaMPCv2KeyGenInitializeCallback = (params: {
+  enterprise: string;
+  bitgoPublicGpgKey: string;
+}) => Promise<{
+  userGpgPublicKey: string;
+  backupGpgPublicKey: string;
+  round1Messages: DklsTypes.AuthEncMessages;
+  userState: ExternalSignerMpcState;
+  backupState: ExternalSignerMpcState;
+}>;
+
+export type EcdsaMPCv2KeyGenRound2Callback = (params: {
+  sessionId: string;
+  bitgoMsg1: MPCv2BroadcastMessage;
+  bitgoToUserMsg2: MPCv2P2PMessage;
+  bitgoToBackupMsg2: MPCv2P2PMessage;
+  userState: ExternalSignerMpcState;
+  backupState: ExternalSignerMpcState;
+}) => Promise<{
+  round2Messages: DklsTypes.AuthEncMessages;
+  userState: ExternalSignerMpcState;
+  backupState: ExternalSignerMpcState;
+}>;
+
+export type EcdsaMPCv2KeyGenRound3Callback = (params: {
+  sessionId: string;
+  bitgoCommitment2: string;
+  bitgoToUserMsg3: MPCv2P2PMessage;
+  bitgoToBackupMsg3: MPCv2P2PMessage;
+  userState: ExternalSignerMpcState;
+  backupState: ExternalSignerMpcState;
+}) => Promise<{
+  round3Messages: DklsTypes.AuthEncMessages;
+  userState: ExternalSignerMpcState;
+  backupState: ExternalSignerMpcState;
+}>;
+
+export type EcdsaMPCv2KeyGenFinalizeCallback = (params: {
+  sessionId: string;
+  bitgoMsg4: MPCv2BroadcastMessage;
+  bitgoCommonKeychain: string;
+  userState: ExternalSignerMpcState;
+  backupState: ExternalSignerMpcState;
+}) => Promise<{ commonKeychain: string }>;
+
+export interface EcdsaMPCv2KeyGenCallbacks {
+  initializeCallback: EcdsaMPCv2KeyGenInitializeCallback;
+  round2Callback: EcdsaMPCv2KeyGenRound2Callback;
+  round3Callback: EcdsaMPCv2KeyGenRound3Callback;
+  finalizeCallback: EcdsaMPCv2KeyGenFinalizeCallback;
+}
+
+export interface EddsaKeyGenInitializeResult {
+  userGpgPublicKey: string;
+  backupGpgPublicKey: string;
+  userToBitgoKeyShare: ExternalSignerKeyShare;
+  backupToBitgoKeyShare: ExternalSignerKeyShare;
+  userState: ExternalSignerMpcState;
+  backupState: ExternalSignerMpcState;
+  backupCounterPartyKeyShare: ExternalSignerKeyShare;
+}
+
+export type EddsaKeyGenInitializeCallback = (params: {
+  enterprise: string;
+  bitgoPublicGpgKey: string;
+}) => Promise<EddsaKeyGenInitializeResult>;
+
+export type EddsaKeyGenFinalizeResult = {
+  commonKeychain: string;
+  counterpartyKeyShare?: ExternalSignerKeyShare;
+};
+
+export type EddsaKeyGenFinalizeCallback = (params: {
+  source: 'user' | 'backup';
+  coin: string;
+  bitgoKeychain: Keychain;
+  counterPartyGPGKey: string;
+  counterPartyKeyShare: ExternalSignerKeyShare;
+  state: ExternalSignerMpcState;
+}) => Promise<EddsaKeyGenFinalizeResult>;
+
+export interface EddsaKeyGenCallbacks {
+  initializeCallback: EddsaKeyGenInitializeCallback;
+  finalizeCallback: EddsaKeyGenFinalizeCallback;
+}
+
 export interface GenerateWalletOptions {
   label?: string;
   passphrase?: string;
@@ -115,9 +216,11 @@ export interface GenerateWalletOptions {
 export interface GenerateWalletWithExternalSignerOptions
   extends Omit<GenerateWalletOptions, 'passphrase' | 'userKey' | 'backupXpub' | 'backupXpubProvider'> {
   label: string;
-  createKeychainCallback: CreateKeychainCallback;
+  createKeychainCallback?: CreateKeychainCallback;
   /** Optional user-key signatures over backup/bitgo pubs. Omit when the external signer cannot produce them (equivalent to a cold wallet). */
   keySignatures?: { backup: string; bitgo: string };
+  ecdsaMPCv2Callbacks?: EcdsaMPCv2KeyGenCallbacks;
+  eddsaCallbacks?: EddsaKeyGenCallbacks;
 }
 
 export const GenerateLightningWalletOptionsCodec = t.intersection(