diff --git a/packages/bcp/src/cosmwasmconnection.spec.ts b/packages/bcp/src/cosmwasmconnection.spec.ts
index 70b8bdb0..55db4b2e 100644
--- a/packages/bcp/src/cosmwasmconnection.spec.ts
+++ b/packages/bcp/src/cosmwasmconnection.spec.ts
@@ -1,4 +1,4 @@
-import { decodeSignature, makeSecp256k1SignatureFromFixedLength } from "@cosmwasm/sdk";
+import { decodeSignature } from "@cosmwasm/sdk";
 import {
   Account,
   Address,
@@ -17,7 +17,7 @@ import {
   TransactionState,
   UnsignedTransaction,
 } from "@iov/bcp";
-import { Random, Secp256k1, Sha256 } from "@iov/crypto";
+import { Random, Secp256k1, Secp256k1Signature, Sha256 } from "@iov/crypto";
 import { Bech32, Encoding } from "@iov/encoding";
 import { HdPaths, Secp256k1HdWallet, UserProfile } from "@iov/keycontrol";
 import { assert } from "@iov/utils";
@@ -475,7 +475,7 @@ describe("CosmWasmConnection", () => {
       const { pubkey, signature } = decodeSignature(encodeFullSignature(signatures[0]));
       const prehashed = new Sha256(signBytes).digest();
       const valid = await Secp256k1.verifySignature(
-        makeSecp256k1SignatureFromFixedLength(signature),
+        Secp256k1Signature.fromFixedLength(signature),
         prehashed,
         pubkey,
       );
diff --git a/packages/sdk/src/index.ts b/packages/sdk/src/index.ts
index 4611ed78..850a3294 100644
--- a/packages/sdk/src/index.ts
+++ b/packages/sdk/src/index.ts
@@ -24,11 +24,7 @@ export {
   encodeSecp256k1Pubkey,
 } from "./pubkey";
 export { findSequenceForSignedTx } from "./sequence";
-export {
-  encodeSecp256k1Signature,
-  decodeSignature,
-  makeSecp256k1SignatureFromFixedLength,
-} from "./signature";
+export { encodeSecp256k1Signature, decodeSignature } from "./signature";
 export {
   SigningCallback,
   SigningCosmWasmClient,
diff --git a/packages/sdk/src/pen.spec.ts b/packages/sdk/src/pen.spec.ts
index 68a514c2..7769893e 100644
--- a/packages/sdk/src/pen.spec.ts
+++ b/packages/sdk/src/pen.spec.ts
@@ -1,8 +1,8 @@
-import { Secp256k1, Sha256 } from "@iov/crypto";
+import { Secp256k1, Secp256k1Signature, Sha256 } from "@iov/crypto";
 import { Encoding } from "@iov/encoding";
 
 import { Secp256k1Pen } from "./pen";
-import { decodeSignature, makeSecp256k1SignatureFromFixedLength } from "./signature";
+import { decodeSignature } from "./signature";
 
 const { fromHex } = Encoding;
 
@@ -37,7 +37,7 @@ describe("Sec256k1Pen", () => {
       const { pubkey, signature } = decodeSignature(await pen.sign(data));
 
       const valid = await Secp256k1.verifySignature(
-        makeSecp256k1SignatureFromFixedLength(signature),
+        Secp256k1Signature.fromFixedLength(signature),
         new Sha256(data).digest(),
         pubkey,
       );
diff --git a/packages/sdk/src/sequence.ts b/packages/sdk/src/sequence.ts
index 9c2ef647..dbdd36a8 100644
--- a/packages/sdk/src/sequence.ts
+++ b/packages/sdk/src/sequence.ts
@@ -1,7 +1,7 @@
-import { Secp256k1, Sha256 } from "@iov/crypto";
+import { Secp256k1, Secp256k1Signature, Sha256 } from "@iov/crypto";
 
 import { makeSignBytes } from "./encoding";
-import { decodeSignature, makeSecp256k1SignatureFromFixedLength } from "./signature";
+import { decodeSignature } from "./signature";
 import { CosmosSdkTx } from "./types";
 
 /**
@@ -26,7 +26,7 @@ export async function findSequenceForSignedTx(
   if (!firstSignature) throw new Error("Signature missing in tx");
 
   const { pubkey, signature } = decodeSignature(firstSignature);
-  const secp256keSignature = makeSecp256k1SignatureFromFixedLength(signature);
+  const secp256keSignature = Secp256k1Signature.fromFixedLength(signature);
 
   for (let s = min; s < upperBound; s++) {
     // console.log(`Trying sequence ${s}`);
diff --git a/packages/sdk/src/signature.ts b/packages/sdk/src/signature.ts
index daa2750c..d31eb119 100644
--- a/packages/sdk/src/signature.ts
+++ b/packages/sdk/src/signature.ts
@@ -1,6 +1,4 @@
-import { Secp256k1Signature } from "@iov/crypto";
 import { Encoding } from "@iov/encoding";
-import BN from "bn.js";
 
 import { encodeSecp256k1Pubkey } from "./pubkey";
 import { pubkeyType, StdSignature } from "./types";
@@ -39,10 +37,3 @@ export function decodeSignature(
       throw new Error("Unsupported pubkey type");
   }
 }
-
-// TODO: use Secp256k1Signature.fromFixedLength once this is published https://github.com/iov-one/iov-core/pull/1401
-export function makeSecp256k1SignatureFromFixedLength(signature: Uint8Array): Secp256k1Signature {
-  const unpaddedR = Uint8Array.from(new BN(signature.slice(0, 32)).toArray());
-  const unpaddedS = Uint8Array.from(new BN(signature.slice(32, 64)).toArray());
-  return new Secp256k1Signature(unpaddedR, unpaddedS);
-}
diff --git a/packages/sdk/types/index.d.ts b/packages/sdk/types/index.d.ts
index b74b8428..2d158036 100644
--- a/packages/sdk/types/index.d.ts
+++ b/packages/sdk/types/index.d.ts
@@ -23,11 +23,7 @@ export {
   encodeSecp256k1Pubkey,
 } from "./pubkey";
 export { findSequenceForSignedTx } from "./sequence";
-export {
-  encodeSecp256k1Signature,
-  decodeSignature,
-  makeSecp256k1SignatureFromFixedLength,
-} from "./signature";
+export { encodeSecp256k1Signature, decodeSignature } from "./signature";
 export {
   SigningCallback,
   SigningCosmWasmClient,
diff --git a/packages/sdk/types/signature.d.ts b/packages/sdk/types/signature.d.ts
index 16c7e432..c23e7167 100644
--- a/packages/sdk/types/signature.d.ts
+++ b/packages/sdk/types/signature.d.ts
@@ -1,4 +1,3 @@
-import { Secp256k1Signature } from "@iov/crypto";
 import { StdSignature } from "./types";
 /**
  * Takes a binary pubkey and signature to create a signature object
@@ -13,4 +12,3 @@ export declare function decodeSignature(
   readonly pubkey: Uint8Array;
   readonly signature: Uint8Array;
 };
-export declare function makeSecp256k1SignatureFromFixedLength(signature: Uint8Array): Secp256k1Signature;