From 9f5984d78d78944cb4e7bd6ba86622e4882b4446 Mon Sep 17 00:00:00 2001
From: Anderson Juhasc <anderson.juhasc@gmail.com>
Date: Sat, 25 May 2024 10:59:45 -0300
Subject: [PATCH] added functions accountFromSeedWords,
 extendedKeysFromSeedWords and accountFromExtendedKey to nip06

---
 nip06.test.ts | 40 +++++++++++++++++++++++++++++++++++++++-
 nip06.ts      | 47 ++++++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 85 insertions(+), 2 deletions(-)

diff --git a/nip06.test.ts b/nip06.test.ts
index 9792afe..4cf4620 100644
--- a/nip06.test.ts
+++ b/nip06.test.ts
@@ -1,5 +1,10 @@
 import { test, expect } from 'bun:test'
-import { privateKeyFromSeedWords } from './nip06.ts'
+import {
+  privateKeyFromSeedWords,
+  accountFromSeedWords,
+  extendedKeysFromSeedWords,
+  accountFromExtendedKey
+} from './nip06.ts'
 
 test('generate private key from a mnemonic', async () => {
   const mnemonic = 'zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo wrong'
@@ -26,3 +31,36 @@ test('generate private key for account 1 from a mnemonic and passphrase', async
   const privateKey = privateKeyFromSeedWords(mnemonic, passphrase, 1)
   expect(privateKey).toEqual('2e0f7bd9e3c3ebcdff1a90fb49c913477e7c055eba1a415d571b6a8c714c7135')
 })
+
+test('generate private and public key for account 1 from a mnemonic and passphrase', async () => {
+  const mnemonic = 'zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo zoo wrong'
+  const passphrase = '123'
+  const { privateKey, publicKey } = accountFromSeedWords(mnemonic, passphrase, 1)
+  expect(privateKey).toEqual('2e0f7bd9e3c3ebcdff1a90fb49c913477e7c055eba1a415d571b6a8c714c7135')
+  expect(publicKey).toEqual('13f55f4f01576570ea342eb7d2b611f9dc78f8dc601aeb512011e4e73b90cf0a')
+})
+
+test('generate extended keys from mnemonic', () => {
+  const mnemonic = 'abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon abandon about'
+  const passphrase = ''
+  const extendedAccountIndex = 0
+  const { privateExtendedKey, publicExtendedKey } = extendedKeysFromSeedWords(mnemonic, passphrase, extendedAccountIndex)
+
+  expect(privateExtendedKey).toBe('xprv9z78fizET65qsCaRr1MSutTSGk1fcKfSt1sBqmuWShtkjRJJ4WCKcSnha6EmgNzFSsyom3MWtydHyPtJtSLZQUtictVQtM2vkPcguh6TQCH')
+  expect(publicExtendedKey).toBe('xpub6D6V5EX8HTe95getx2tTH2QApmrA1nPJFEnneAK813RjcDdSc3WaAF7BRNpTF7o7zXjVm3DD3VMX66jhQ7wLaZ9sS6NzyfiwfzqDZbxvpDN')
+})
+
+test('generate account from extended private key', () => {
+  const xprv = 'xprv9z78fizET65qsCaRr1MSutTSGk1fcKfSt1sBqmuWShtkjRJJ4WCKcSnha6EmgNzFSsyom3MWtydHyPtJtSLZQUtictVQtM2vkPcguh6TQCH'
+  const { privateKey, publicKey } = accountFromExtendedKey(xprv)
+
+  expect(privateKey).toBe('5f29af3b9676180290e77a4efad265c4c2ff28a5302461f73597fda26bb25731')
+  expect(publicKey).toBe('e8bcf3823669444d0b49ad45d65088635d9fd8500a75b5f20b59abefa56a144f')
+})
+
+test('generate account from extended public key', () => {
+  const xpub = 'xpub6D6V5EX8HTe95getx2tTH2QApmrA1nPJFEnneAK813RjcDdSc3WaAF7BRNpTF7o7zXjVm3DD3VMX66jhQ7wLaZ9sS6NzyfiwfzqDZbxvpDN'
+  const { publicKey } = accountFromExtendedKey(xpub)
+
+  expect(publicKey).toBe('e8bcf3823669444d0b49ad45d65088635d9fd8500a75b5f20b59abefa56a144f')
+})
diff --git a/nip06.ts b/nip06.ts
index 9a80253..3909bb7 100644
--- a/nip06.ts
+++ b/nip06.ts
@@ -3,13 +3,58 @@ import { wordlist } from '@scure/bip39/wordlists/english'
 import { generateMnemonic, mnemonicToSeedSync, validateMnemonic } from '@scure/bip39'
 import { HDKey } from '@scure/bip32'
 
+const DERIVATION_PATH = `m/44'/1237'`
+
 export function privateKeyFromSeedWords(mnemonic: string, passphrase?: string, accountIndex = 0): string {
   let root = HDKey.fromMasterSeed(mnemonicToSeedSync(mnemonic, passphrase))
-  let privateKey = root.derive(`m/44'/1237'/${accountIndex}'/0/0`).privateKey
+  let privateKey = root.derive(`${DERIVATION_PATH}/${accountIndex}'/0/0`).privateKey
   if (!privateKey) throw new Error('could not derive private key')
   return bytesToHex(privateKey)
 }
 
+export function accountFromSeedWords(mnemonic: string, passphrase?: string, accountIndex = 0): {
+  privateKey: string,
+  publicKey: string,
+} {
+  const root = HDKey.fromMasterSeed(mnemonicToSeedSync(mnemonic, passphrase))
+  const seed = root.derive(`${DERIVATION_PATH}/${accountIndex}'/0/0`)
+  const privateKey = bytesToHex(seed.privateKey!)
+  const publicKey = bytesToHex(seed.publicKey!.slice(1))
+  if (!privateKey && !publicKey) {
+    throw new Error('could not derive key pair')
+  }
+  return { privateKey, publicKey }
+}
+
+export function extendedKeysFromSeedWords(mnemonic: string, passphrase?: string, extendedAccountIndex = 0): {
+  privateExtendedKey: string,
+  publicExtendedKey: string
+} {
+  let root = HDKey.fromMasterSeed(mnemonicToSeedSync(mnemonic, passphrase))
+  let seed = root.derive(`${DERIVATION_PATH}/${extendedAccountIndex}'`)
+  let privateExtendedKey = seed.privateExtendedKey
+  let publicExtendedKey = seed.publicExtendedKey
+  if (!privateExtendedKey && !publicExtendedKey) throw new Error('could not derive extended key pair')
+  return { privateExtendedKey, publicExtendedKey }
+}
+
+export function accountFromExtendedKey(base58key: string, accountIndex = 0): {
+  privateKey?: string,
+  publicKey: string
+} {
+  let extendedKey = HDKey.fromExtendedKey(base58key)
+  let version = base58key.slice(0, 4)
+  let child = extendedKey.deriveChild(0).deriveChild(accountIndex)
+  let publicKey = bytesToHex(child.publicKey!.slice(1))
+  if (!publicKey) throw new Error('could not derive public key')
+  if (version === 'xprv') {
+    let privateKey = bytesToHex(child.privateKey!)
+    if (!privateKey) throw new Error('could not derive private key')
+    return { privateKey, publicKey } 
+  }
+  return { publicKey } 
+}
+
 export function generateSeedWords(): string {
   return generateMnemonic(wordlist)
 }