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.
 
 - node now no longer supports older than v20
 - overriding cross spawn for patch

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";
@@ -894,4 +904,44 @@ 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: Secp256k1Signature | AnySignature;
+    recoveryBit?: number;
+    accountAddress: AccountAddressInput;
+  }): Promise<AnyPublicKey> {
+    return verifySecp256k1Account({ aptosConfig: this.config, ...args });
+  }
 }

src/core/crypto/secp256k1.ts

@@ -4,6 +4,7 @@
 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";
@@ -13,6 +14,9 @@ import { PublicKey, VerifySignatureArgs } from "./publicKey";
 import { Signature } from "./signature";
 import { convertSigningMessage } from "./utils";
 
+const secp256k1P = BigInt("0xfffffffffffffffffffffffffffffffffffffffffffffffffffffffefffffc2f");
+const secp256k1N = BigInt("0xfffffffffffffffffffffffffffffffebaaedce6af48a03bbfd25e8cd0364141");
+
 /**
  * Represents a Secp256k1 ECDSA public key.
  *
@@ -150,6 +154,35 @@ export class Secp256k1PublicKey extends PublicKey {
   static isInstance(publicKey: PublicKey): publicKey is Secp256k1PublicKey {
     return "key" in publicKey && (publicKey.key as any)?.data?.length === Secp256k1PublicKey.LENGTH;
   }
+
+  /**
+   * Recover a Secp256k1 public key from a signature and message.
+   *
+   * @param args - The arguments for recovering the public key.
+   * @param args.signature - The signature to recover the public key from.
+   * @param args.message - The message that was signed.
+   * @param args.recoveryBit - The recovery bit to use for the public key.
+   */
+  static fromSignatureAndMessage(args: {
+    signature: Secp256k1Signature;
+    message: HexInput;
+    recoveryBit: number;
+  }): Secp256k1PublicKey {
+    const { signature, message, recoveryBit } = args;
+    const signatureBytes: Uint8Array = signature.toUint8Array();
+
+    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 nobleSig = new secp256k1.Signature(r, s);
+
+    const messageToVerify = convertSigningMessage(message);
+    const messageBytes = Hex.fromHexInput(messageToVerify).toUint8Array();
+    const messageSha3Bytes = sha3_256(messageBytes);
+    const publicKeyBytes = nobleSig.addRecoveryBit(recoveryBit).recoverPublicKey(messageSha3Bytes).toRawBytes(false);
+    return new Secp256k1PublicKey(publicKeyBytes);
+  }
 }
 
 /**
@@ -367,6 +400,11 @@ export class Secp256k1Signature extends Signature {
    */
   static readonly LENGTH = 64;
 
+  /**
+   * Automatically added when constructed or de-serialized.  Used for type checking.
+   */
+  private readonly signatureType = "secp256k1";
+
   /**
    * The signature bytes
    * @private
@@ -417,4 +455,20 @@ export class Secp256k1Signature extends Signature {
   }
 
   // endregion
+
+  /**
+   * Determines if the provided signature is a valid instance of a Secp256k1 signature.
+   * This function checks for the presence of a "data" property and validates the length of the signature data.
+   *
+   * @param signature - The signature to validate.
+   * @returns A boolean indicating whether the signature is a valid Secp256k1 signature.
+   */
+  static isInstance(signature: any): signature is Secp256k1Signature {
+    return (
+      "signatureType" in signature &&
+      signature.signatureType === "secp256k1" &&
+      "data" in signature &&
+      (signature.data.data as any)?.length === Secp256k1Signature.LENGTH
+    );
+  }
 }

src/core/crypto/singleKey.ts

@@ -1,5 +1,10 @@
 import { Deserializer, Serializer } from "../../bcs";
-import { AnyPublicKeyVariant, AnySignatureVariant, SigningScheme as AuthenticationKeyScheme } from "../../types";
+import {
+  AnyPublicKeyVariant,
+  AnySignatureVariant,
+  SigningScheme as AuthenticationKeyScheme,
+  HexInput,
+} from "../../types";
 import { AuthenticationKey } from "../authenticationKey";
 import { Ed25519PrivateKey, Ed25519PublicKey, Ed25519Signature } from "./ed25519";
 import { AccountPublicKey, PublicKey, VerifySignatureArgs } from "./publicKey";
@@ -212,6 +217,30 @@ export class AnyPublicKey extends AccountPublicKey {
   static isInstance(publicKey: PublicKey): publicKey is AnyPublicKey {
     return "publicKey" in publicKey && "variant" in publicKey;
   }
+
+  /**
+   * Recover a Secp256k1 AnyPublicKey from a signature and message.
+   *
+   * @param args.signature - The signature to recover the public key from.
+   * @param args.message - The message that was signed.
+   * @param args.recoveryBit - The recovery bit to use for the public key.
+   */
+  static fromSecp256k1SignatureAndMessage(args: {
+    signature: AnySignature;
+    message: HexInput;
+    recoveryBit: number;
+  }): AnyPublicKey {
+    const { signature, message, recoveryBit } = args;
+    if (!Secp256k1Signature.isInstance(signature.signature)) {
+      throw new Error("AnySignature variant is not Secp256k1");
+    }
+    const publicKey = Secp256k1PublicKey.fromSignatureAndMessage({
+      signature: signature.signature,
+      message,
+      recoveryBit,
+    });
+    return new AnyPublicKey(publicKey);
+  }
 }
 
 /**

src/internal/account.ts

@@ -17,6 +17,7 @@ import {
   GetAccountOwnedTokensFromCollectionResponse,
   GetAccountOwnedTokensQueryResponse,
   GetObjectDataQueryResponse,
+  HexInput,
   LedgerVersionArg,
   MoveModuleBytecode,
   MoveResource,
@@ -29,7 +30,7 @@ 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, Secp256k1Signature } from "../core/crypto";
 import { queryIndexer } from "./general";
 import {
   GetAccountCoinsCountQuery,
@@ -815,3 +816,92 @@ export async function isAccountExist(args: { aptosConfig: AptosConfig; authKey:
     throw new Error(`Error while looking for an account info ${accountAddress.toString()}`);
   }
 }
+
+/**
+ * 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.aptosConfig - The configuration for connecting to the Aptos blockchain.
+ * @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 { AptosConfig, Network } from "@aptos-labs/ts-sdk";
+ *
+ * const config = new AptosConfig({ network: Network.DEVNET });
+ *
+ * const publicKey = await verifySecp256k1Account({
+ *   aptosConfig,
+ *   message: "0x1234...",
+ *   signature: "0x5678...",
+ *   accountAddress: "0x1"
+ * });
+ * ```
+ */
+export async function verifySecp256k1Account(args: {
+  aptosConfig: AptosConfig;
+  message: HexInput;
+  signature: Secp256k1Signature | AnySignature;
+  accountAddress: AccountAddressInput;
+  recoveryBit?: number;
+}): Promise<AnyPublicKey> {
+  const { aptosConfig, message, recoveryBit, accountAddress } = args;
+  const signature = AnySignature.isInstance(args.signature) ? args.signature : new AnySignature(args.signature);
+
+  const { authentication_key: authKeyString } = await getInfo({
+    aptosConfig,
+    accountAddress,
+  });
+  const authKey = new AuthenticationKey({ data: authKeyString });
+
+  if (recoveryBit !== undefined) {
+    const publicKey = AnyPublicKey.fromSecp256k1SignatureAndMessage({
+      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 = AnyPublicKey.fromSecp256k1SignatureAndMessage({
+        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()}`,
+  );
+}

src/utils/helpers.ts

@@ -2,7 +2,7 @@
 // SPDX-License-Identifier: Apache-2.0
 
 import { decode } from "js-base64";
-import { MoveStructId } from "../types";
+import { HexInput, MoveStructId } from "../types";
 
 /**
  * Sleep for the specified amount of time in milliseconds.
@@ -175,3 +175,11 @@ export const isEncodedStruct = (
   typeof structObj.account_address === "string" &&
   typeof structObj.module_name === "string" &&
   typeof structObj.struct_name === "string";
+
+/**
+ * Type guard to check if a value is of type HexInput
+ * @param value The value to check
+ */
+export function isHexInput(value: unknown): value is HexInput {
+  return value instanceof Uint8Array || typeof value === "string";
+}