From 6b3ef713e906002f3148e2eea75a2342dff334e8 Mon Sep 17 00:00:00 2001
From: Felicio Mununga <felicio@users.noreply.github.com>
Date: Thu, 23 Feb 2023 16:48:31 +0100
Subject: [PATCH] Add public key deserialization (#341)

* add `multiformats` dep

* add `deserialize-public-key.ts`

* compress by default

* add tests

* Update packages/status-js/src/utils/deserialize-public-key.ts

Co-authored-by: Pavel <14926950+prichodko@users.noreply.github.com>

* rename vars

---------

Co-authored-by: Pavel <14926950+prichodko@users.noreply.github.com>
---
 packages/status-js/package.json               |  3 +-
 .../src/utils/deserialize-public-key.test.ts  | 45 ++++++++++++
 .../src/utils/deserialize-public-key.ts       | 73 +++++++++++++++++++
 yarn.lock                                     |  5 ++
 4 files changed, 125 insertions(+), 1 deletion(-)
 create mode 100644 packages/status-js/src/utils/deserialize-public-key.test.ts
 create mode 100644 packages/status-js/src/utils/deserialize-public-key.ts

diff --git a/packages/status-js/package.json b/packages/status-js/package.json
index 434e3960..c4fad170 100644
--- a/packages/status-js/package.json
+++ b/packages/status-js/package.json
@@ -35,7 +35,8 @@
   "dependencies": {
     "@bufbuild/protobuf": "^1.0.0",
     "ethereum-cryptography": "^1.0.3",
-    "js-waku": "^0.30.0"
+    "js-waku": "^0.30.0",
+    "multiformats": "^11.0.1"
   },
   "devDependencies": {
     "@bufbuild/protoc-gen-es": "^1.0.0"
diff --git a/packages/status-js/src/utils/deserialize-public-key.test.ts b/packages/status-js/src/utils/deserialize-public-key.test.ts
new file mode 100644
index 00000000..daca7dcd
--- /dev/null
+++ b/packages/status-js/src/utils/deserialize-public-key.test.ts
@@ -0,0 +1,45 @@
+import { expect, test } from 'vitest'
+
+import { deserializePublicKey } from './deserialize-public-key'
+
+test('should deserialize public key from compressed base58btc encoding', () => {
+  expect(
+    deserializePublicKey('zQ3shY7r4cAdg4eUF5dfcuCqCFzWmdjHW4SX5hspM9ucAarfU')
+  ).toEqual(
+    '0x029f196bbfef4fa6a5eb81dd802133a63498325445ca1af1d154b1bb4542955133'
+  )
+})
+
+test('should deserialize public key from compressed hexadecimal encoding', () => {
+  expect(
+    deserializePublicKey(
+      '0x029f196bbfef4fa6a5eb81dd802133a63498325445ca1af1d154b1bb4542955133'
+    )
+  ).toEqual(
+    '0x029f196bbfef4fa6a5eb81dd802133a63498325445ca1af1d154b1bb4542955133'
+  )
+})
+
+test('should deserialize public key from uncompressed hexadecimal encoding', () => {
+  expect(
+    deserializePublicKey(
+      '0x049f196bbfef4fa6a5eb81dd802133a63498325445ca1af1d154b1bb454295513305b23fcf11d005ee622144fc402b713a8928f80d705781e2e78d701c6e01bfc4'
+    )
+  ).toEqual(
+    '0x029f196bbfef4fa6a5eb81dd802133a63498325445ca1af1d154b1bb4542955133'
+  )
+})
+
+test('should throw when deserializing unsupported multibase encoding', () => {
+  expect(() =>
+    deserializePublicKey('ZQ3shY7r4cAdg4eUF5dfcuCqCFzWmdjHW4SX5hspM9ucAarfU')
+  ).toThrowError()
+})
+
+test('should throw when deserializing invalid public key', () => {
+  expect(() =>
+    deserializePublicKey(
+      '0x019f196bbfef4fa6a5eb81dd802133a63498325445ca1af1d154b1bb4542955133'
+    )
+  ).toThrowError()
+})
diff --git a/packages/status-js/src/utils/deserialize-public-key.ts b/packages/status-js/src/utils/deserialize-public-key.ts
new file mode 100644
index 00000000..989562a0
--- /dev/null
+++ b/packages/status-js/src/utils/deserialize-public-key.ts
@@ -0,0 +1,73 @@
+import { Point } from 'ethereum-cryptography/secp256k1'
+import {
+  toHex,
+  // utf8ToBytes as toBytes, // see https://github.com/paulmillr/noble-hashes/blob/d76eb7c818931d290c4c27abb778e8e269895154/src/utils.ts#L91-L96
+} from 'ethereum-cryptography/utils'
+import { varint } from 'multiformats'
+import { base58btc } from 'multiformats/bases/base58'
+
+/**
+ * @see https://github.com/multiformats/multibase/blob/af2d36bdfaeaca453d20b18542ca57bd56b51f6c/README.md#multibase-table
+ */
+const VALID_MULTIBASE_CODES = [
+  'f', // hexadecimal
+  'z', // base58btc
+] as const
+
+type MultibaseCode = typeof VALID_MULTIBASE_CODES[number]
+
+/**
+ * @see https://pkg.go.dev/github.com/multiformats/go-multicodec#pkg-types
+ */
+const VALID_MULTICODEC_CODES = [
+  231, // secp256k1-pub (compressed) (0xe7)
+] as const
+
+type MulticodecCode = typeof VALID_MULTICODEC_CODES[number]
+
+/**
+ * @see https://specs.status.im/spec/2#public-key-serialization for specification
+ */
+export function deserializePublicKey(
+  publicKey: string, // uncompressed, compressed, or compressed & encoded
+  options = { compress: true }
+): string {
+  const multibasePublicKey = publicKey.replace(/^0[xX]/, 'f') // ensure multibase code for hexadecimal encoding
+  const multibaseCode = multibasePublicKey[0] as MultibaseCode
+
+  if (!VALID_MULTIBASE_CODES.includes(multibaseCode)) {
+    throw new Error('Invalid public key multibase code')
+  }
+
+  let hexadecimalPublicKey: string
+  switch (multibaseCode) {
+    case 'z': {
+      const base58btcPublicKey = base58btc.decode(multibasePublicKey)
+      const multicodec = varint.decode(base58btcPublicKey)
+      const multicodecCode = multicodec[0] as MulticodecCode
+      const multicodecCodeByteLength = multicodec[1]
+
+      if (!VALID_MULTICODEC_CODES.includes(multicodecCode)) {
+        throw new Error('Invalid public key multicodec code')
+      }
+
+      hexadecimalPublicKey = toHex(
+        base58btcPublicKey.slice(multicodecCodeByteLength)
+      )
+
+      break
+    }
+
+    case 'f': {
+      hexadecimalPublicKey = multibasePublicKey.slice(1)
+
+      break
+    }
+
+    default: {
+      throw new Error('Unsupported public key multicodec code')
+    }
+  }
+
+  return `0x${Point.fromHex(hexadecimalPublicKey).toHex(options.compress)}` // validates and sets compression
+}
diff --git a/yarn.lock b/yarn.lock
index cd9ff53d..6a89a170 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -5429,6 +5429,11 @@ ms@^2.1.1:
   resolved "https://registry.yarnpkg.com/ms/-/ms-2.1.3.tgz#574c8138ce1d2b5861f0b44579dbadd60c6615b2"
   integrity sha512-6FlzubTLZG3J2a/NVCAleEhjzq5oxgHyaCU9yYXvcLsvoVaHJq/s5xXI6/XXP6tz7R9xAOtHnSO/tXtF3WRTlA==
 
+multiformats@^11.0.1:
+  version "11.0.1"
+  resolved "https://registry.yarnpkg.com/multiformats/-/multiformats-11.0.1.tgz#ba58c3f69f032ab67dab4b48cc70f01ac2ca07fe"
+  integrity sha512-atWruyH34YiknSdL5yeIir00EDlJRpHzELYQxG7Iy29eCyL+VrZHpPrX5yqlik3jnuqpLpRKVZ0SGVb9UzKaSA==
+
 multiformats@^9.4.2, multiformats@^9.4.5:
   version "9.6.4"
   resolved "https://registry.yarnpkg.com/multiformats/-/multiformats-9.6.4.tgz#5dce1f11a407dbb69aa612cb7e5076069bb759ca"