Add secp256k1 verify and pubKey recovery function

CHANGELOG.md

@@ -3,6 +3,7 @@
 All notable changes to the Aptos TypeScript SDK will be captured in this file. This changelog is written by hand for now. It adheres to the format set out by [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 # Unreleased
+- Added `verifySecp256k1Account` function to verify secp256k1 signatures to prove account ownership. Also enables public key recovery for such accounts.
 
 # 1.33.0 (2024-11-13)
 - Allow optional provision of public keys in transaction simulation

src/api/account.ts

@@ -2,7 +2,15 @@
 // SPDX-License-Identifier: Apache-2.0
 
 import { Account as AccountModule } from "../account";
-import { AccountAddress, PrivateKey, AccountAddressInput, createObjectAddress } from "../core";
+import {
+  AccountAddress,
+  PrivateKey,
+  AccountAddressInput,
+  createObjectAddress,
+  Secp256k1Signature,
+  AnyPublicKey,
+  AnySignature,
+} from "../core";
 import {
   AccountData,
   AnyNumber,
@@ -11,6 +19,7 @@ import {
   GetAccountOwnedTokensFromCollectionResponse,
   GetAccountOwnedTokensQueryResponse,
   GetObjectDataQueryResponse,
+  HexInput,
   LedgerVersionArg,
   MoveModuleBytecode,
   MoveResource,
@@ -39,6 +48,7 @@ import {
   getResources,
   getTransactions,
   lookupOriginalAccountAddress,
+  verifySecp256k1Account,
 } from "../internal/account";
 import { APTOS_COIN, APTOS_FA, ProcessorType } from "../utils/const";
 import { AptosConfig } from "./aptosConfig";
@@ -874,4 +884,44 @@ export class Account {
   async deriveAccountFromPrivateKey(args: { privateKey: PrivateKey }): Promise<AccountModule> {
     return deriveAccountFromPrivateKey({ aptosConfig: this.config, ...args });
   }
+
+  /**
+   * Verifies a Secp256k1 account by checking the signature against the message and account's authentication key.
+   *
+   * This function takes a message and signature, and attempts to recover the public key that created the signature.
+   * It then verifies that the recovered public key matches the authentication key stored on-chain for the provided account address.
+   *
+   * If a recovery bit is provided, it will only attempt verification with that specific recovery bit.
+   * Otherwise, it will try all possible recovery bits (0-3) until it finds a match.
+   *
+   * @param args - The arguments for verifying the Secp256k1 account
+   * @param args.message - The message that was signed
+   * @param args.signature - The signature to verify (either raw hex or Secp256k1Signature object)
+   * @param args.recoveryBit - Optional specific recovery bit to use for verification
+   * @param args.accountAddress - The address of the account to verify
+   * @returns The recovered public key if verification succeeds
+   * @throws Error if verification fails or no matching public key is found
+   *
+   * @example
+   * ```typescript
+   * import { Aptos, AptosConfig, Network } from "@aptos-labs/ts-sdk";
+   *
+   * const config = new AptosConfig({ network: Network.DEVNET });
+   * const aptos = new Aptos(config);
+   *
+   * const publicKey = await aptos.verifySecp256k1Account({
+   *   message: "0x1234...",
+   *   signature: "0x5678...",
+   *   accountAddress: "0x1"
+   * });
+   * ```
+   */
+  async verifySecp256k1Account(args: {
+    message: HexInput;
+    signature: HexInput | Secp256k1Signature | AnySignature;
+    recoveryBit?: number;
+    accountAddress: AccountAddressInput;
+  }): Promise<AnyPublicKey> {
+    return verifySecp256k1Account({ aptosConfig: this.config, ...args });
+  }
 }

src/core/crypto/secp256k1.ts

@@ -4,15 +4,19 @@
 import { sha3_256 } from "@noble/hashes/sha3";
 import { secp256k1 } from "@noble/curves/secp256k1";
 import { HDKey } from "@scure/bip32";
+import { bytesToNumberBE, inRange } from "@noble/curves/abstract/utils";
 import { Serializable, Deserializer, Serializer } from "../../bcs";
 import { Hex } from "../hex";
 import { HexInput, PrivateKeyVariants } from "../../types";
 import { isValidBIP44Path, mnemonicToSeed } from "./hdKey";
 import { PrivateKey } from "./privateKey";
-import { PublicKey, VerifySignatureArgs } from "./publicKey";
+import { PublicKey } from "./publicKey";
 import { Signature } from "./signature";
 import { convertSigningMessage } from "./utils";
 
+const secp256k1P = BigInt("0xfffffffffffffffffffffffffffffffffffffffffffffffffffffffefffffc2f");
+const secp256k1N = BigInt("0xfffffffffffffffffffffffffffffffebaaedce6af48a03bbfd25e8cd0364141");
+
 /**
  * Represents a Secp256k1 ECDSA public key.
  *
@@ -53,7 +57,7 @@ export class Secp256k1PublicKey extends PublicKey {
    * @param args.message - The message that was signed.
    * @param args.signature - The signature to verify against the public key.
    */
-  verifySignature(args: VerifySignatureArgs): boolean {
+  verifySignature(args: { message: HexInput; signature: Secp256k1Signature }): boolean {
     const { message, signature } = args;
     const messageToVerify = convertSigningMessage(message);
     const messageBytes = Hex.fromHexInput(messageToVerify).toUint8Array();
@@ -124,6 +128,33 @@ export class Secp256k1PublicKey extends PublicKey {
   static isInstance(publicKey: PublicKey): publicKey is Secp256k1PublicKey {
     return "key" in publicKey && (publicKey.key as any)?.data?.length === Secp256k1PublicKey.LENGTH;
   }
+
+  static fromSignatureAndMessage(args: {
+    signature: HexInput | Secp256k1Signature;
+    message: HexInput;
+    recoveryBit: number;
+  }): Secp256k1PublicKey {
+    const { signature, message, recoveryBit } = args;
+    let signatureBytes: Uint8Array;
+    if (signature instanceof Secp256k1Signature) {
+      signatureBytes = signature.toUint8Array();
+    } else {
+      signatureBytes = Hex.fromHexInput(signature).toUint8Array();
+      if (signatureBytes.length !== Secp256k1Signature.LENGTH) {
+        throw new Error(`Signature length should be ${Secp256k1Signature.LENGTH}`);
+      }
+    }
+    const r = bytesToNumberBE(signatureBytes.subarray(0, 32)); // Let r = int(sig[0:32]); fail if r ≥ p.
+    if (!inRange(r, BigInt(1), secp256k1P)) throw new Error("Invalid secp256k1 signature - r ≥ p");
+    const s = bytesToNumberBE(signatureBytes.subarray(32, 64)); // Let s = int(sig[32:64]); fail if s ≥ n.
+    if (!inRange(s, BigInt(1), secp256k1N)) throw new Error("Invalid secp256k1 signature - s ≥ n");
+    const sig = new secp256k1.Signature(r, s);
+    const messageToVerify = convertSigningMessage(message);
+    const messageBytes = Hex.fromHexInput(messageToVerify).toUint8Array();
+    const messageSha3Bytes = sha3_256(messageBytes);
+    const publicKeyBytes = sig.addRecoveryBit(recoveryBit).recoverPublicKey(messageSha3Bytes).toRawBytes(false);
+    return new Secp256k1PublicKey(publicKeyBytes);
+  }
 }
 
 /**

src/internal/account.ts

@@ -16,6 +16,7 @@ import {
   GetAccountOwnedTokensFromCollectionResponse,
   GetAccountOwnedTokensQueryResponse,
   GetObjectDataQueryResponse,
+  HexInput,
   LedgerVersionArg,
   MoveModuleBytecode,
   MoveResource,
@@ -28,7 +29,14 @@ import {
 } from "../types";
 import { AccountAddress, AccountAddressInput } from "../core/accountAddress";
 import { Account } from "../account";
-import { AnyPublicKey, Ed25519PublicKey, PrivateKey } from "../core/crypto";
+import {
+  AnyPublicKey,
+  AnySignature,
+  Ed25519PublicKey,
+  PrivateKey,
+  Secp256k1PublicKey,
+  Secp256k1Signature,
+} from "../core/crypto";
 import { queryIndexer } from "./general";
 import {
   GetAccountCoinsCountQuery,
@@ -795,3 +803,72 @@ export async function isAccountExist(args: { aptosConfig: AptosConfig; authKey:
     throw new Error(`Error while looking for an account info ${accountAddress.toString()}`);
   }
 }
+
+export async function verifySecp256k1Account(args: {
+  aptosConfig: AptosConfig;
+  message: HexInput;
+  signature: HexInput | Secp256k1Signature | AnySignature;
+  recoveryBit?: number;
+  accountAddress: AccountAddressInput;
+}): Promise<AnyPublicKey> {
+  const { aptosConfig, message, recoveryBit, accountAddress } = args;
+  let signature: HexInput | Secp256k1Signature;
+  if (args.signature instanceof AnySignature) {
+    if (args.signature.signature instanceof Secp256k1Signature) {
+      signature = args.signature.signature;
+    } else {
+      throw new Error("Invalid signature type");
+    }
+  } else {
+    signature = args.signature;
+  }
+  const { authentication_key: authKeyString } = await getInfo({
+    aptosConfig,
+    accountAddress,
+  });
+  const authKey = new AuthenticationKey({ data: authKeyString });
+
+  if (recoveryBit !== undefined) {
+    const publicKey = new AnyPublicKey(
+      Secp256k1PublicKey.fromSignatureAndMessage({
+        signature,
+        message,
+        recoveryBit,
+      }),
+    );
+    const derivedAuthKey = publicKey.authKey();
+    if (authKey.toStringWithoutPrefix() === derivedAuthKey.toStringWithoutPrefix()) {
+      return publicKey;
+    }
+    throw new Error(
+      // eslint-disable-next-line max-len
+      `Derived authentication key ${derivedAuthKey.toString()} does not match the authentication key ${authKey.toString()} for account ${accountAddress.toString()}`,
+    );
+  }
+
+  for (let i = 0; i < 4; i += 1) {
+    try {
+      const publicKey = new AnyPublicKey(
+        Secp256k1PublicKey.fromSignatureAndMessage({
+          signature,
+          message,
+          recoveryBit: i,
+        }),
+      );
+      const derivedAuthKey = publicKey.authKey();
+      if (authKey.toStringWithoutPrefix() === derivedAuthKey.toStringWithoutPrefix()) {
+        return publicKey;
+      }
+    } catch (e) {
+      if (e instanceof Error && e.message.includes("recovery id")) {
+        // eslint-disable-next-line no-continue
+        continue;
+      }
+      throw e;
+    }
+  }
+
+  throw new Error(
+    `Failed to recover the public key matching authentication key ${authKey.toString()} for account ${accountAddress.toString()}`,
+  );
+}

tests/e2e/api/account.test.ts

@@ -11,6 +11,8 @@ import {
   SigningSchemeInput,
   U64,
   AccountAddress,
+  SingleKeyAccount,
+  Secp256k1PrivateKey,
 } from "../../../src";
 import { getAptosClient } from "../helper";
 
@@ -301,6 +303,52 @@ describe("account api", () => {
       expect(tokens[0].current_token_data?.token_name).toBe("Test Token");
     });
 
+    test("it verifies a secp256k1 signature", async () => {
+      const config = new AptosConfig({ network: Network.LOCAL });
+      const aptos = new Aptos(config);
+      const account = new SingleKeyAccount({
+        privateKey: new Secp256k1PrivateKey(
+          "secp256k1-priv-0x1111111111111111111111111111111111111111111111111111111111111111",
+        ),
+      });
+      await aptos.fundAccount({ accountAddress: account.accountAddress, amount: 100 });
+      const message = new TextEncoder().encode("hello");
+      const signature = account.sign(message);
+
+      const pubKey = await aptos.verifySecp256k1Account({
+        message,
+        signature,
+        accountAddress: account.accountAddress,
+      });
+      expect(pubKey.toString()).toBe(account.publicKey.toString());
+
+      await expect(
+        aptos.verifySecp256k1Account({
+          message: new TextEncoder().encode("hi"),
+          signature,
+          accountAddress: account.accountAddress,
+        }),
+      ).rejects.toThrow("Failed to recover the public key");
+
+      await expect(
+        aptos.verifySecp256k1Account({
+          message,
+          signature,
+          accountAddress: account.accountAddress,
+          recoveryBit: 0,
+        }),
+      ).rejects.toThrow("does not match the authentication key");
+
+      await expect(
+        aptos.verifySecp256k1Account({
+          message,
+          signature,
+          accountAddress: account.accountAddress,
+          recoveryBit: 3,
+        }),
+      ).rejects.toThrow("recovery id 2 or 3 invalid");
+    });
+
     describe("it derives an account from a private key", () => {
       test("single sender ed25519", async () => {
         const config = new AptosConfig({ network: Network.LOCAL });