Merge pull request #67 from swan-bitcoin/jdf/remove-tinysecp-from-lib

remove tiny-secp256k1 from xpub-lib dependencies, add initEccLib function, require for taproot

Author: turkycat

packages/xpub-cli/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@swan-bitcoin/xpub-cli",
-  "version": "0.2.0",
+  "version": "0.3.0",
   "description": "Command-line wrapper around @swan-bitcoin/xpub-lib",
   "keywords": [
     "bitcoin",
@@ -53,8 +53,9 @@
     "test": "echo \"Warning: no test specified\""
   },
   "dependencies": {
-    "@swan-bitcoin/xpub-lib": "^0.2.0",
-    "commander": "^6.1.0"
+    "@swan-bitcoin/xpub-lib": "^0.3.0",
+    "commander": "^6.1.0",
+    "tiny-secp256k1": "^2.2.3"
   },
   "devDependencies": {
     "@babel/cli": "^7.11.6",

packages/xpub-cli/src/xpub.js

@@ -2,12 +2,14 @@
 
 const {
   Network,
+  initEccLib,
   isValidAddress,
   isValidExtPubKey,
   addressFromExtPubKey,
   addressesFromExtPubKey,
   Purpose,
 } = require("@swan-bitcoin/xpub-lib")
+const ecc = require('tiny-secp256k1')
 const { version } = require("../package.json")
 
 function parsePurpose(purpose) {
@@ -72,6 +74,8 @@ program
       cmdObj.help()
     }
 
+    initEccLib(ecc)
+
     const network = cmdObj.testnet ? Network.TESTNET : Network.MAINNET
     if (!isValidExtPubKey(extPubKey, network)) {
       console.error(`error: invalid extended public key '${extPubKey}'`)

packages/xpub-lib/README.md

@@ -37,6 +37,22 @@ addressFromExtPubKey({ extPubKey: key, network: "mainnet" })
 // }
 ```
 
+For taproot addresses, you must first initialize an instance of an ECC library implementing the secp256k1 elliptic curve interface, such as [tiny-secp256k1](https://www.npmjs.com/package/tiny-secp256k1).
+
+```
+const ecc = require('tiny-secp256k1')
+initEccLib(ecc)
+
+const key = "xpub6EuV33a2DXxAhoJTRTnr8qnysu81AA4YHpLY6o8NiGkEJ8KADJ35T64eJsStWsmRf1xXkEANVjXFXnaUKbRtFwuSPCLfDdZwYNZToh4LBCd"
+
+addressFromExtPubKey({ extPubKey: key, network: "mainnet", purpose: Purpose.P2TR })
+
+// {
+//     path: "m/86'/0'/0'/0/0",
+//     address: 'bc1ptpvckxtuurh4t26yls5s6t5j9hyy2fh945zfpad44ngxdxqm0s2qhk3ljc'
+// }
+```
+
 Use `addressesFromExtPubKey` to derive multiple addresses. The following
 example derives the first three addresses of the first account from a `vpub`
 extended public key on testnet.
@@ -68,7 +84,7 @@ addressesFromExtPubKey({
 To derive wrapped SegWit addresses
 (starting with `3...`) specify the appropriate purpose with `purpose: Purpose.P2SH`.
 
-For more examples refer to the tests of this library.
+For more examples refer to the tests of this library or the implementation of the CLI tool.
 
 ## Relevant BIPs and Educational Resources
 

packages/xpub-lib/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@swan-bitcoin/xpub-lib",
-  "version": "0.2.0",
+  "version": "0.3.0",
   "description": "A JavaScript library for bitcoin address derivation from extended public keys, built upon bitcoinjs-lib and Unchained's bitcoin utilities. Supports P2PKH, P2SH, and P2WPKH (bech32) addresses as defined in BIP44, BIP49, and BIP84.",
   "author": "Pablof7z <pablo@swan.com>",
   "license": "MIT",
@@ -34,8 +34,7 @@
   ],
   "dependencies": {
     "@caravan/bitcoin": "^0.3.1",
-    "bitcoinjs-lib": "^6.1.7",
-    "tiny-secp256k1": "^2.2.3"
+    "bitcoinjs-lib": "^6.1.7"
   },
   "scripts": {
     "babel-version": "babel --version",
@@ -58,6 +57,7 @@
     "babel-jest": "^26.3.0",
     "jest": "^26.4.2",
     "livereload": "^0.9.1",
-    "nodemon": "^2.0.4"
+    "nodemon": "^2.0.4",
+    "tiny-secp256k1": "^2.2.3"
   }
 }

packages/xpub-lib/src/derivation.js

@@ -5,7 +5,6 @@
  */
 
 import * as bitcoin from "bitcoinjs-lib"
-import * as ecc from 'tiny-secp256k1';
 import { toXOnly } from 'bitcoinjs-lib/src/psbt/bip371';
 import { deriveChildPublicKey, networkData, Network } from "@caravan/bitcoin"
 import { fullDerivationPath, partialKeyDerivationPath } from "./paths"
@@ -35,7 +34,20 @@ const DEFAULT_NETWORK = Network.TESTNET
  * */
 const DEFAULT_PURPOSE = Purpose.P2WPKH
 
-bitcoin.initEccLib(ecc);
+/**
+ * The secp256k1 interface to use for Taproot address derivation.
+ */
+let eccInstance = null;
+
+/**
+ * Initialize the ECC library for Taproot address derivation.
+ *
+ * @param {object} eccLib - The secp256k1 interface to use.
+ */
+function initEccLib(eccLib) {
+  eccInstance = eccLib;
+  bitcoin.initEccLib(eccInstance);
+}
 
 /**
  * Derive a single address from a public key.
@@ -73,7 +85,9 @@ function deriveAddress({ purpose, pubkey, network }) {
       return bc1qAddress
     }
     case Purpose.P2TR: {
-      // Context: https://bitcoinops.org/en/topics/x-only-public-keys/
+      if (!eccInstance) {
+        throw new Error("An instance of an ECC library implementing the secp256k1 curve must be initialized to generate taproot addresses. You must first call initEccLib().");
+      }
       const xOnlyPubkey = toXOnly(pubkey)
       const { address: bc1pAddress } = bitcoin.payments.p2tr({
         internalPubkey:  xOnlyPubkey,
@@ -176,4 +190,4 @@ function addressesFromExtPubKey({
   return addresses
 }
 
-export { addressFromExtPubKey, addressesFromExtPubKey }
+export { addressFromExtPubKey, addressesFromExtPubKey, initEccLib }

packages/xpub-lib/src/derivation.test.js

@@ -1,7 +1,12 @@
 import { Network } from "@caravan/bitcoin"
 import { KEY, KEYS, WASABI, SAMOURAI } from "../test/fixtures"
 import { Purpose } from "./purpose"
-import { addressFromExtPubKey, addressesFromExtPubKey } from "./derivation"
+import { addressFromExtPubKey, addressesFromExtPubKey, initEccLib } from "./derivation"
+import * as ecc from "tiny-secp256k1"
+
+beforeAll(() => {
+  initEccLib(ecc)
+})
 
 describe("addressFromExtPubKey() with invalid xpubs", () => {
   test("address generation from invalid xpub fails", () => {