diff --git a/packages/launchpad/src/secp256k1key.spec.ts b/packages/launchpad/src/secp256k1key.spec.ts
new file mode 100644
index 00000000..643a4b21
--- /dev/null
+++ b/packages/launchpad/src/secp256k1key.spec.ts
@@ -0,0 +1,54 @@
+/* eslint-disable @typescript-eslint/naming-convention */
+import { Secp256k1, Secp256k1Signature, Sha256 } from "@cosmjs/crypto";
+import { fromBase64, fromHex } from "@cosmjs/encoding";
+
+import { serializeSignDoc, StdSignDoc } from "./encoding";
+import { Secp256k1Key } from "./secp256k1key";
+
+describe("Secp256k1Key", () => {
+  const defaultPrivkey = fromHex("b8c462d2bb0c1a92edf44f735021f16c270f28ee2c3d1cb49943a5e70a3c763e");
+  const defaultAddress = "cosmos1kxt5x5q2l57ma2d434pqpafxdm0mgeg9c8cvtx";
+  const defaultPubkey = fromHex("03f146c27639179e5b67b8646108f48e1a78b146c74939e34afaa5414ad5c93f8a");
+
+  describe("fromPrivkey", () => {
+    it("works", async () => {
+      const signer = await Secp256k1Key.fromPrivkey(defaultPrivkey);
+      expect(signer).toBeTruthy();
+    });
+  });
+
+  describe("getAccounts", () => {
+    it("resolves to a list of accounts", async () => {
+      const signer = await Secp256k1Key.fromPrivkey(defaultPrivkey);
+      const accounts = await signer.getAccounts();
+      expect(accounts.length).toEqual(1);
+      expect(accounts[0]).toEqual({
+        address: defaultAddress,
+        algo: "secp256k1",
+        pubkey: defaultPubkey,
+      });
+    });
+  });
+
+  describe("sign", () => {
+    it("resolves to valid signature if enabled", async () => {
+      const signer = await Secp256k1Key.fromPrivkey(defaultPrivkey);
+      const signDoc: StdSignDoc = {
+        msgs: [],
+        fee: { amount: [], gas: "23" },
+        chain_id: "foochain",
+        memo: "hello, world",
+        account_number: "7",
+        sequence: "54",
+      };
+      const { signed, signature } = await signer.sign(defaultAddress, signDoc);
+      expect(signed).toEqual(signDoc);
+      const valid = await Secp256k1.verifySignature(
+        Secp256k1Signature.fromFixedLength(fromBase64(signature.signature)),
+        new Sha256(serializeSignDoc(signed)).digest(),
+        defaultPubkey,
+      );
+      expect(valid).toEqual(true);
+    });
+  });
+});
diff --git a/packages/launchpad/src/secp256k1key.ts b/packages/launchpad/src/secp256k1key.ts
new file mode 100644
index 00000000..33bde15f
--- /dev/null
+++ b/packages/launchpad/src/secp256k1key.ts
@@ -0,0 +1,56 @@
+import { Secp256k1, Sha256 } from "@cosmjs/crypto";
+
+import { rawSecp256k1PubkeyToAddress } from "./address";
+import { serializeSignDoc, StdSignDoc } from "./encoding";
+import { encodeSecp256k1Signature } from "./signature";
+import { AccountData, OfflineSigner, SignResponse } from "./signer";
+
+export class Secp256k1Key implements OfflineSigner {
+  /**
+   * Creates a Secp256k1 key signer from the given private key
+   *
+   * @param privkey The private key.
+   * @param prefix The bech32 address prefix (human readable part). Defaults to "cosmos".
+   */
+  public static async fromPrivkey(privkey: Uint8Array, prefix = "cosmos"): Promise<Secp256k1Key> {
+    const uncompressed = (await Secp256k1.makeKeypair(privkey)).pubkey;
+    return new Secp256k1Key(privkey, Secp256k1.compressPubkey(uncompressed), prefix);
+  }
+
+  private readonly pubkey: Uint8Array;
+  private readonly privkey: Uint8Array;
+  private readonly prefix: string;
+
+  private constructor(privkey: Uint8Array, pubkey: Uint8Array, prefix: string) {
+    this.privkey = privkey;
+    this.pubkey = pubkey;
+    this.prefix = prefix;
+  }
+
+  private get address(): string {
+    return rawSecp256k1PubkeyToAddress(this.pubkey, this.prefix);
+  }
+
+  public async getAccounts(): Promise<readonly AccountData[]> {
+    return [
+      {
+        algo: "secp256k1",
+        address: this.address,
+        pubkey: this.pubkey,
+      },
+    ];
+  }
+
+  public async sign(signerAddress: string, signDoc: StdSignDoc): Promise<SignResponse> {
+    if (signerAddress !== this.address) {
+      throw new Error(`Address ${signerAddress} not found in wallet`);
+    }
+    const message = new Sha256(serializeSignDoc(signDoc)).digest();
+    const signature = await Secp256k1.createSignature(message, this.privkey);
+    const signatureBytes = new Uint8Array([...signature.r(32), ...signature.s(32)]);
+    return {
+      signed: signDoc,
+      signature: encodeSecp256k1Signature(this.pubkey, signatureBytes),
+    };
+  }
+}
diff --git a/packages/launchpad/types/secp256k1key.d.ts b/packages/launchpad/types/secp256k1key.d.ts
new file mode 100644
index 00000000..1f5d6edc
--- /dev/null
+++ b/packages/launchpad/types/secp256k1key.d.ts
@@ -0,0 +1,18 @@
+import { StdSignDoc } from "./encoding";
+import { AccountData, OfflineSigner, SignResponse } from "./signer";
+export declare class Secp256k1Key implements OfflineSigner {
+  /**
+   * Creates a Secp256k1 key signer from the given private key
+   *
+   * @param privkey The private key.
+   * @param prefix The bech32 address prefix (human readable part). Defaults to "cosmos".
+   */
+  static fromPrivkey(privkey: Uint8Array, prefix?: string): Promise<Secp256k1Key>;
+  private readonly pubkey;
+  private readonly privkey;
+  private readonly prefix;
+  private constructor();
+  private get address();
+  getAccounts(): Promise<readonly AccountData[]>;
+  sign(signerAddress: string, signDoc: StdSignDoc): Promise<SignResponse>;
+}