diff --git a/lib/net/bip150.js b/lib/net/bip150.js
index 36905e40..2cea3c45 100644
--- a/lib/net/bip150.js
+++ b/lib/net/bip150.js
@@ -470,7 +470,7 @@ function AuthDB(options) {
   this.prefix = null;
   this.dnsKnown = [];
 
-  this.known = {};
+  this.known = new Map();
   this.authorized = [];
 
   this._init(options);
@@ -556,7 +556,7 @@ AuthDB.prototype.addKnown = function addKnown(host, key) {
     return;
   }
 
-  this.known[host] = key;
+  this.known.set(host, key);
 };
 
 /**
@@ -578,7 +578,7 @@ AuthDB.prototype.addAuthorized = function addAuthorized(key) {
 AuthDB.prototype.setKnown = function setKnown(map) {
   let keys = Object.keys(map);
 
-  this.known = {};
+  this.known.clear();
 
   for (let host of keys) {
     let key = map[host];
@@ -605,7 +605,7 @@ AuthDB.prototype.setAuthorized = function setAuthorized(keys) {
  */
 
 AuthDB.prototype.getKnown = function getKnown(hostname) {
-  let known = this.known[hostname];
+  let known = this.known.get(hostname);
   let addr;
 
   if (known)
@@ -613,7 +613,7 @@ AuthDB.prototype.getKnown = function getKnown(hostname) {
 
   addr = IP.fromHostname(hostname);
 
-  return this.known[addr.host];
+  return this.known.get(addr.host);
 };
 
 /**
@@ -625,8 +625,8 @@ AuthDB.prototype.getKnown = function getKnown(hostname) {
 AuthDB.prototype.lookup = async function lookup() {
   let jobs = [];
 
-  for (let addr of this.dnsKnown)
-    jobs.push(this.populate(addr[0], addr[1]));
+  for (let [addr, key] of this.dnsKnown)
+    jobs.push(this.populate(addr, key));
 
   await Promise.all(jobs);
 };
@@ -658,7 +658,7 @@ AuthDB.prototype.populate = async function populate(addr, key) {
     if (addr.port !== 0)
       host = IP.toHostname(host, addr.port);
 
-    this.known[host] = key;
+    this.known.set(host, key);
   }
 };