feat: Add compact protobuf format

README.md

@@ -175,6 +175,10 @@ Returns `Promise<PeerId>`.
 
 Returns `Promise<PeerId>`.
 
+### `createFromProtobuf(buf)`
+
+`buf` is a protocol-buffers encoded PeerId (see `marshal()`)
+
 ## Export
 
 ### `toHexString()`
@@ -209,6 +213,10 @@ Returns an `obj` of the form
 - `obj.pubKey: String` - The public key in protobuf format, encoded in 'base64'
 - `obj.privKey: String` - The private key in protobuf format, encoded in 'base 64'
 
+### `marshal(excludePrivatKey)`
+
+Returns a protocol-buffers encoded version of the id, public key and, if `excludePrivateKey` is not set, the private key.
+
 ### `toPrint()`
 
 Returns the Peer ID as a printable string without the `Qm` prefix.

package.json

@@ -42,7 +42,8 @@
   "dependencies": {
     "class-is": "^1.1.0",
     "libp2p-crypto": "~0.17.0",
-    "multihashes": "~0.4.15"
+    "multihashes": "~0.4.15",
+    "protons": "^1.0.1"
   },
   "repository": {
     "type": "git",

src/index.js

@@ -8,6 +8,7 @@ const mh = require('multihashes')
 const cryptoKeys = require('libp2p-crypto/src/keys')
 const assert = require('assert')
 const withIs = require('class-is')
+const { PeerIdProto } = require('./proto')
 
 class PeerId {
   constructor (id, privKey, pubKey) {
@@ -67,6 +68,15 @@ class PeerId {
     }
   }
 
+  // Return the protobuf version of the peer-id
+  marshal (excludePriv) {
+    return PeerIdProto.encode({
+      id: this.toBytes(),
+      pubKey: this.marshalPubKey(),
+      privKey: excludePriv ? null : this.marshalPrivKey()
+    })
+  }
+
   toPrint () {
     let pid = this.toB58String()
     // All sha256 nodes start with Qm
@@ -232,6 +242,49 @@ exports.createFromJSON = async (obj) => {
   return new PeerIdWithIs(id, privKey, pub)
 }
 
+exports.createFromProtobuf = async (buf) => {
+  if (typeof buf === 'string') {
+    buf = Buffer.from(buf, 'hex')
+  }
+
+  let { id, privKey, pubKey } = PeerIdProto.decode(buf)
+
+  privKey = privKey ? await cryptoKeys.unmarshalPrivateKey(privKey) : false
+  pubKey = pubKey ? await cryptoKeys.unmarshalPublicKey(pubKey) : false
+
+  let pubDigest
+  let privDigest
+
+  if (privKey) {
+    privDigest = await computeDigest(privKey.public)
+  }
+
+  if (pubKey) {
+    pubDigest = await computeDigest(pubKey)
+  }
+
+  if (privKey) {
+    if (pubKey) {
+      if (!privDigest.equals(pubDigest)) {
+        throw new Error('Public and private key do not match')
+      }
+    }
+    return new PeerIdWithIs(privDigest, privKey, privKey.public)
+  }
+
+  // TODO: val id and pubDigest
+
+  if (pubKey) {
+    return new PeerIdWithIs(pubDigest, null, pubKey)
+  }
+
+  if (id) {
+    return new PeerIdWithIs(id)
+  }
+
+  throw new Error('Protobuf did not contain any usable key material')
+}
+
 exports.isPeerId = (peerId) => {
   return Boolean(typeof peerId === 'object' &&
     peerId._id &&

src/proto.js

@@ -0,0 +1,12 @@
+'use strict'
+
+const protons = require('protons')
+module.exports = protons(`
+
+message PeerIdProto {
+  required bytes id = 1;
+  bytes pubKey = 2;
+  bytes privKey = 3;
+}
+
+`)

test/peer-id.spec.js

@@ -86,6 +86,16 @@ describe('PeerId', () => {
     expect(id.marshalPubKey()).to.deep.equal(id2.marshalPubKey())
   })
 
+  it('Recreate from Protobuf', async () => {
+    const id = await PeerId.createFromProtobuf(testId.marshaled)
+    expect(testIdB58String).to.equal(id.toB58String())
+    const encoded = Buffer.from(testId.privKey, 'base64')
+    const id2 = await PeerId.createFromPrivKey(encoded)
+    expect(testIdB58String).to.equal(id2.toB58String())
+    expect(id.marshalPubKey()).to.deep.equal(id2.marshalPubKey())
+    expect(id.marshal().toString('hex')).to.deep.equal(testId.marshaled)
+  })
+
   it('can be created from a Secp256k1 public key', async () => {
     const privKey = await crypto.keys.generateKeyPair('secp256k1', 256)
     const id = await PeerId.createFromPubKey(privKey.public.bytes)
@@ -200,7 +210,7 @@ describe('PeerId', () => {
       Buffer.from(''), 'aGVsbG93b3JsZA==', 'helloworld', ''
     ]
 
-    const fncs = ['createFromPubKey', 'createFromPrivKey', 'createFromJSON']
+    const fncs = ['createFromPubKey', 'createFromPrivKey', 'createFromJSON', 'createFromProtobuf']
 
     for (const gb of garbage) {
       for (const fn of fncs) {