feat(mpc-service): add blockchain-service client for address derivation

- Add BlockchainClientService to call blockchain-service /internal/derive-address
- Call derive addresses after keygen completes with MPC public key
- Include derived addresses (BSC, KAVA, DST) in keygen completed event

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

backend/services/mpc-service/src/application/event-handlers/keygen-requested.handler.ts

@@ -14,6 +14,7 @@ import {
   KeygenRequestedPayload,
 } from '../../infrastructure/messaging/kafka/event-consumer.service';
 import { BackupClientService } from '../../infrastructure/external/backup';
+import { BlockchainClientService } from '../../infrastructure/external/blockchain';
 import { KeygenStartedEvent } from '../../domain/events/keygen-started.event';
 import { KeygenCompletedEvent } from '../../domain/events/keygen-completed.event';
 import { SessionFailedEvent } from '../../domain/events/session-failed.event';
@@ -28,6 +29,7 @@ export class KeygenRequestedHandler implements OnModuleInit {
     private readonly eventPublisher: EventPublisherService,
     private readonly mpcCoordinator: MPCCoordinatorService,
     private readonly backupClient: BackupClientService,
+    private readonly blockchainClient: BlockchainClientService,
   ) {}
 
   async onModuleInit() {
@@ -74,6 +76,20 @@ export class KeygenRequestedHandler implements OnModuleInit {
         // Cache public key
         await this.mpcCoordinator.savePublicKeyCache(username, result.publicKey);
 
+        // Step 3: Derive addresses for all chains (BSC, KAVA, DST) via blockchain-service
+        let derivedAddresses: { chainType: string; address: string }[] = [];
+        try {
+          const deriveResult = await this.blockchainClient.deriveAddresses({
+            userId,
+            publicKey: result.publicKey,
+          });
+          derivedAddresses = deriveResult.addresses;
+          this.logger.log(`Addresses derived: userId=${userId}, count=${derivedAddresses.length}`);
+        } catch (deriveError) {
+          // 地址派生失败不阻塞主流程，但记录错误
+          this.logger.error(`Failed to derive addresses: userId=${userId}`, deriveError);
+        }
+
         // Save delegate share to backup-service if exists
         if (result.delegateShare) {
           // 1. 保存到本地缓存（用于签名时快速访问）
@@ -115,6 +131,7 @@ export class KeygenRequestedHandler implements OnModuleInit {
           userId,
           username,
           delegateShare: result.delegateShare,
+          derivedAddresses, // BSC, KAVA, DST addresses
           serverParties: [], // mpc-system manages this
         };
 

backend/services/mpc-service/src/infrastructure/external/blockchain/blockchain-client.service.ts

@@ -0,0 +1,102 @@
+/**
+ * Blockchain Client Service
+ *
+ * mpc-service 调用 blockchain-service 派生钱包地址
+ */
+
+import { Injectable, Logger } from '@nestjs/common';
+import { HttpService } from '@nestjs/axios';
+import { ConfigService } from '@nestjs/config';
+import { firstValueFrom } from 'rxjs';
+
+export interface DeriveAddressParams {
+  userId: string;
+  publicKey: string;
+}
+
+export interface DerivedAddress {
+  chainType: string;
+  address: string;
+}
+
+export interface DeriveAddressResult {
+  userId: string;
+  publicKey: string;
+  addresses: DerivedAddress[];
+}
+
+@Injectable()
+export class BlockchainClientService {
+  private readonly logger = new Logger(BlockchainClientService.name);
+  private readonly blockchainServiceUrl: string;
+
+  constructor(
+    private readonly httpService: HttpService,
+    private readonly configService: ConfigService,
+  ) {
+    this.blockchainServiceUrl = this.configService.get<string>(
+      'BLOCKCHAIN_SERVICE_URL',
+      'http://blockchain-service:3000',
+    );
+    this.logger.log(`[INIT] BlockchainClientService initialized`);
+    this.logger.log(`[INIT] URL: ${this.blockchainServiceUrl}`);
+  }
+
+  /**
+   * 从公钥派生多链地址 (BSC, KAVA, DST)
+   */
+  async deriveAddresses(params: DeriveAddressParams): Promise<DeriveAddressResult> {
+    this.logger.log(`Deriving addresses: userId=${params.userId}, publicKey=${params.publicKey.substring(0, 20)}...`);
+
+    try {
+      const response = await firstValueFrom(
+        this.httpService.post<DeriveAddressResult>(
+          `${this.blockchainServiceUrl}/internal/derive-address`,
+          {
+            userId: params.userId,
+            publicKey: params.publicKey,
+          },
+          {
+            headers: {
+              'Content-Type': 'application/json',
+            },
+            timeout: 30000,
+          },
+        ),
+      );
+
+      this.logger.log(`Addresses derived successfully: userId=${params.userId}, count=${response.data.addresses.length}`);
+      for (const addr of response.data.addresses) {
+        this.logger.log(`  ${addr.chainType}: ${addr.address}`);
+      }
+
+      return response.data;
+    } catch (error) {
+      this.logger.error(`Failed to derive addresses: userId=${params.userId}`, error);
+      throw error;
+    }
+  }
+
+  /**
+   * 获取用户已有的地址
+   */
+  async getUserAddresses(userId: string): Promise<DerivedAddress[]> {
+    this.logger.log(`Getting user addresses: userId=${userId}`);
+
+    try {
+      const response = await firstValueFrom(
+        this.httpService.get<{ userId: string; addresses: DerivedAddress[] }>(
+          `${this.blockchainServiceUrl}/internal/user/${userId}/addresses`,
+          {
+            timeout: 30000,
+          },
+        ),
+      );
+
+      return response.data.addresses;
+    } catch (error) {
+      this.logger.error(`Failed to get user addresses: userId=${userId}`, error);
+      throw error;
+    }
+  }
+}

backend/services/mpc-service/src/infrastructure/external/blockchain/index.ts

@@ -0,0 +1 @@
+export * from './blockchain-client.service';

backend/services/mpc-service/src/infrastructure/infrastructure.module.ts

@@ -5,6 +5,7 @@
  * - PrismaService 用于缓存公钥和 delegate share
  * - Kafka 事件发布和消费
  * - BackupClientService 用于存储 delegate share 到 backup-service
+ * - BlockchainClientService 用于派生钱包地址
  */
 
 import { Global, Module } from '@nestjs/common';
@@ -20,6 +21,7 @@ import { EventConsumerService } from './messaging/kafka/event-consumer.service';
 
 // External Services
 import { BackupClientService } from './external/backup';
+import { BlockchainClientService } from './external/blockchain';
 
 @Global()
 @Module({
@@ -40,12 +42,14 @@ import { BackupClientService } from './external/backup';
 
     // External Services
     BackupClientService,
+    BlockchainClientService,
   ],
   exports: [
     PrismaService,
     EventPublisherService,
     EventConsumerService,
     BackupClientService,
+    BlockchainClientService,
   ],
 })
 export class InfrastructureModule {}