diff --git a/packages/bcp/src/cosmwasmcodec.spec.ts b/packages/bcp/src/cosmwasmcodec.spec.ts
index 405a2db8..d2ceeba0 100644
--- a/packages/bcp/src/cosmwasmcodec.spec.ts
+++ b/packages/bcp/src/cosmwasmcodec.spec.ts
@@ -2,7 +2,7 @@ import { PostableBytes, PrehashType } from "@iov/bcp";
 import { Encoding } from "@iov/encoding";
 
 import { cosmWasmCodec } from "./cosmwasmcodec";
-import { chainId, nonce, sendTxJson, signedTxBin, signedTxJson, txId } from "./testdata.spec";
+import { chainId, nonce, sendTxJson, signedTxBin, signedTxJson } from "./testdata.spec";
 
 const { toUtf8 } = Encoding;
 
@@ -35,12 +35,6 @@ describe("cosmWasmCodec", () => {
     expect(decoded).toEqual(signedTxJson);
   });
 
-  xit("generates transaction id", () => {
-    const id = cosmWasmCodec.identifier(signedTxJson);
-    expect(id).toMatch(/^[0-9A-F]{64}$/);
-    expect(id).toEqual(txId);
-  });
-
   it("round trip works", () => {
     const encoded = cosmWasmCodec.bytesToPost(signedTxJson);
     const decoded = cosmWasmCodec.parseBytes(encoded, chainId, nonce);
diff --git a/packages/bcp/src/cosmwasmconnection.spec.ts b/packages/bcp/src/cosmwasmconnection.spec.ts
index 8ef2a08e..a87b431e 100644
--- a/packages/bcp/src/cosmwasmconnection.spec.ts
+++ b/packages/bcp/src/cosmwasmconnection.spec.ts
@@ -17,6 +17,7 @@ import { HdPaths, Secp256k1HdWallet, UserProfile } from "@iov/keycontrol";
 import { CosmosBech32Prefix } from "./address";
 import { CosmWasmCodec, cosmWasmCodec } from "./cosmwasmcodec";
 import { CosmWasmConnection, TokenConfiguration } from "./cosmwasmconnection";
+import { signedTxJson, txId } from "./testdata.spec";
 import { nonceToSequence } from "./types";
 
 const { fromBase64, toHex } = Encoding;
@@ -133,6 +134,17 @@ describe("CosmWasmConnection", () => {
     });
   });
 
+  describe("encodeTx", () => {
+    it("properly calculates tx hash", async () => {
+      pendingWithoutCosmos();
+      const connection = await CosmWasmConnection.establish(httpUrl, defaultPrefix, defaultTokens);
+      const postable = cosmWasmCodec.bytesToPost(signedTxJson);
+      const id = await connection.identifier(postable);
+      expect(id).toMatch(/^[0-9A-F]{64}$/);
+      expect(id).toEqual(txId);
+    });
+  });
+
   describe("getAccount", () => {
     it("gets an empty account by address", async () => {
       pendingWithoutCosmos();
diff --git a/packages/bcp/src/cosmwasmconnection.ts b/packages/bcp/src/cosmwasmconnection.ts
index 7abf2904..d3c09490 100644
--- a/packages/bcp/src/cosmwasmconnection.ts
+++ b/packages/bcp/src/cosmwasmconnection.ts
@@ -1,5 +1,5 @@
 /* eslint-disable @typescript-eslint/camelcase */
-import { RestClient, TxsResponse } from "@cosmwasm/sdk";
+import { RestClient, TxsResponse, unmarshalTx } from "@cosmwasm/sdk";
 import {
   Account,
   AccountQuery,
@@ -27,7 +27,8 @@ import {
   TransactionState,
   UnsignedTransaction,
 } from "@iov/bcp";
-import { Uint53 } from "@iov/encoding";
+import { Sha256 } from "@iov/crypto";
+import { Encoding, Uint53 } from "@iov/encoding";
 import { DefaultValueProducer, ValueAndUpdates } from "@iov/stream";
 import equal from "fast-deep-equal";
 import { ReadonlyDate } from "readonly-date";
@@ -38,6 +39,8 @@ import { Caip5 } from "./caip5";
 import { decodeAmount, parseTxsResponse } from "./decode";
 import { accountToNonce, TokenInfo } from "./types";
 
+const { toHex } = Encoding;
+
 interface ChainData {
   readonly chainId: ChainId;
 }
@@ -138,6 +141,13 @@ export class CosmWasmConnection implements BlockchainConnection {
     return this.supportedTokens;
   }
 
+  public async identifier(signed: PostableBytes): Promise<TransactionId> {
+    const tx = unmarshalTx(signed);
+    const bytes = await this.restClient.encodeTx(tx);
+    const hash = new Sha256(bytes).digest();
+    return toHex(hash).toUpperCase() as TransactionId;
+  }
+
   public async getAccount(query: AccountQuery): Promise<Account | undefined> {
     const address = isPubkeyQuery(query) ? pubkeyToAddress(query.pubkey, this.prefix) : query.address;
     const { result } = await this.restClient.authAccounts(address);
diff --git a/packages/bcp/types/cosmwasmconnection.d.ts b/packages/bcp/types/cosmwasmconnection.d.ts
index c3c2f616..982ac756 100644
--- a/packages/bcp/types/cosmwasmconnection.d.ts
+++ b/packages/bcp/types/cosmwasmconnection.d.ts
@@ -45,6 +45,7 @@ export declare class CosmWasmConnection implements BlockchainConnection {
   height(): Promise<number>;
   getToken(searchTicker: TokenTicker): Promise<Token | undefined>;
   getAllTokens(): Promise<readonly Token[]>;
+  identifier(signed: PostableBytes): Promise<TransactionId>;
   getAccount(query: AccountQuery): Promise<Account | undefined>;
   watchAccount(_account: AccountQuery): Stream<Account | undefined>;
   getNonce(query: AddressQuery | PubkeyQuery): Promise<Nonce>;