wip bip340 key tweaking

Author: matthiasgeihs

demo/redirect-flow-example/package-lock.json

@@ -26,6 +26,7 @@ import{ tssLib as tssLibFrostBip340 } from "@toruslabs/tss-frost-lib-bip340";
 import "./App.css";
 import jwt, { Algorithm } from "jsonwebtoken";
 import { flow } from "./flow";
+import { ec as EC } from "elliptic";
 
 type TssLib = typeof tssLibDkls | typeof tssLibFrost | typeof tssLibFrostBip340;
 
@@ -401,16 +402,29 @@ function App() {
       uiConsole(sig.toString("hex"));
     }
   };
+
+  const signWithKeyTweak = async (): Promise<any> => {
+    if (coreKitInstance.sigType === SIG_TYPE.ECDSA_SECP256K1) {
+      throw new Error("Not supported for this signature type");
+    } else if (coreKitInstance.sigType === SIG_TYPE.ED25519 || coreKitInstance.sigType === SIG_TYPE.BIP340) {
+      const msg = Buffer.from("hello signer!");
+      const keyTweak = (() => {
+        const ec = new EC(coreKitInstance.keyType);
+        return ec.genKeyPair().getPrivate();
+      })();
+      const sig = await coreKitInstance.sign(msg, { keyTweak });
+      uiConsole(sig.toString("hex"));
+    }
+  };
+
   const signMessageWithPrecomputedTss = async (): Promise<any> => {
     if (coreKitInstance.keyType === "secp256k1") {
       const precomputedTssClient = await coreKitInstance.precompute_secp256k1();
       const msg = Buffer.from("hello signer!");
-      const sig = await coreKitInstance.sign(msg, false, precomputedTssClient);
-      uiConsole(sig.toString("hex"));
-    } else if (coreKitInstance.keyType === "ed25519") {
-      const msg = Buffer.from("hello signer!");
-      const sig = await coreKitInstance.sign(msg);
+      const sig = await coreKitInstance.sign(msg, { secp256k1Precompute: precomputedTssClient });
       uiConsole(sig.toString("hex"));
+    } else {
+      throw new Error("Not supported for this key type");
     }
   };
 
@@ -419,15 +433,13 @@ function App() {
       const [precomputedTssClient, precomputedTssClient2] = await Promise.all([coreKitInstance.precompute_secp256k1(), coreKitInstance.precompute_secp256k1()]);
 
       const msg = Buffer.from("hello signer!");
-      const sig = await coreKitInstance.sign(msg, false, precomputedTssClient);
+      const sig = await coreKitInstance.sign(msg, { secp256k1Precompute: precomputedTssClient });
       const msg2 = Buffer.from("hello signer2!");
 
-      const sig2 = await coreKitInstance.sign(msg2, false, precomputedTssClient2);
+      const sig2 = await coreKitInstance.sign(msg2, { secp256k1Precompute: precomputedTssClient2 });
       uiConsole("Sig1: ", sig.toString("hex"), "Sig2: ", sig2.toString("hex"));
-    } else if (coreKitInstance.keyType === "ed25519") {
-      const msg = Buffer.from("hello signer!");
-      const sig = await coreKitInstance.sign(msg);
-      uiConsole(sig.toString("hex"));
+    } else {
+      throw new Error("Not supported for this key type");
     }
   };
   const switchChainSepolia = async () => {
@@ -746,8 +758,12 @@ function App() {
           Sign Message
         </button>
 
+        <button onClick={signWithKeyTweak} className="card">
+          Sign with Key Tweak
+        </button>
+
         <button onClick={signMessageWithPrecomputedTss} className="card">
-          Sign Msgwith precomputed TSS
+          Sign with precomputed TSS
         </button>
 
         <button onClick={signMultipleMessagesWithPrecomputedTss} className="card">

demo/redirect-flow-example/src/App.tsx

@@ -62,8 +62,8 @@
     "@toruslabs/session-manager": "^3.1.0",
     "@toruslabs/torus.js": "^15.1.1",
     "@toruslabs/tss-client": "^3.3.0-alpha.0",
-    "@toruslabs/tss-frost-client": "^1.0.0-alpha.0",
-    "@toruslabs/tss-frost-common": "^1.0.1",
+    "@toruslabs/tss-frost-client": "file:toruslabs-tss-frost-client-1.0.0-alpha.1.tgz",
+    "@toruslabs/tss-frost-common": "file:toruslabs-tss-frost-common-1.1.0-alpha.0.tgz",
     "bn.js": "^5.2.1",
     "bowser": "^2.11.0",
     "elliptic": "^6.5.7",

package-lock.json

@@ -463,7 +463,7 @@ export type SigType = WEB3AUTH_SIG_TYPE;
 export interface CoreKitSigner {
   keyType: KeyType;
   sigType: SigType;
-  sign(data: Buffer, hashed?: boolean): Promise<Buffer>;
+  sign(data: Buffer, opts?: { hashed?: boolean }): Promise<Buffer>;
   getPubKey(): Buffer;
 }
 

package.json

@@ -768,13 +768,27 @@ export class Web3AuthMPCCoreKit implements ICoreKit {
     };
   }
 
-  public async sign(data: Buffer, hashed: boolean = false, secp256k1Precompute?: Secp256k1PrecomputedClient): Promise<Buffer> {
+  public async sign(
+    data: Buffer,
+    opts?: {
+      hashed?: boolean;
+      secp256k1Precompute?: Secp256k1PrecomputedClient;
+      keyTweak?: BN;
+    }
+  ): Promise<Buffer> {
     this.wasmLib = await this.loadTssWasm();
     if (this._sigType === "ecdsa-secp256k1") {
-      const sig = await this.sign_ECDSA_secp256k1(data, hashed, secp256k1Precompute);
+      if (opts?.keyTweak) {
+        throw CoreKitError.default("key tweaking not supported for ecdsa-secp256k1");
+      }
+      const sig = await this.sign_ECDSA_secp256k1(data, opts?.hashed, opts?.secp256k1Precompute);
       return Buffer.concat([sig.r, sig.s, Buffer.from([sig.v])]);
     } else if (this._sigType === "ed25519" || this._sigType === "bip340") {
-      return this.sign_frost(data, hashed);
+      if (opts?.hashed) {
+        throw CoreKitError.default(`hashed data not supported for bip340`);
+      }
+
+      return this.sign_frost(data, opts?.keyTweak);
     }
     throw CoreKitError.default(`sign not supported for key type ${this.keyType}`);
   }
@@ -1407,11 +1421,7 @@ export class Web3AuthMPCCoreKit implements ICoreKit {
     }
   }
 
-  private async sign_frost(data: Buffer, hashed: boolean = false): Promise<Buffer> {
-    if (hashed) {
-      throw CoreKitError.default(`hashed data not supported for ${this._sigType}`);
-    }
-
+  private async sign_frost(data: Buffer, keyTweak?: BN): Promise<Buffer> {
     const nodeDetails = fetchLocalConfig(this.options.web3AuthNetwork, this.keyType, this._sigType);
     if (!nodeDetails.torusNodeTSSEndpoints) {
       throw CoreKitError.default("could not fetch tss node endpoints");
@@ -1439,7 +1449,7 @@ export class Web3AuthMPCCoreKit implements ICoreKit {
     const { serverCoefficients, clientCoefficient } = deriveShareCoefficients(ec, serverXCoords, clientXCoord, this.state.tssShareIndex);
 
     // Get pub key.
-    const tssPubKey = await this.getPubKey();
+    const tssPubKey = this.getPubKey();
     const tssPubKeyPoint = ec.keyFromPublic(tssPubKey).getPublic();
 
     // Get client key share and adjust by coefficient.
@@ -1469,7 +1479,8 @@ export class Web3AuthMPCCoreKit implements ICoreKit {
       clientShareAdjustedHex,
       pubKeyHex,
       data,
-      serverCoefficientsHex
+      serverCoefficientsHex,
+      keyTweak?.toString("hex")
     );
 
     log.info(`signature: ${signature}`);

src/interfaces.ts

@@ -201,7 +201,7 @@ export function makeEthereumSigner(kit: CoreKitSigner): EthereumSigner {
   }
   return {
     sign: async (msgHash: Buffer) => {
-      const sig = await kit.sign(msgHash, true);
+      const sig = await kit.sign(msgHash, { hashed: true });
       return sigToRSV(sig);
     },
     getPublic: async () => {