diff --git a/src/pubsub.js b/src/pubsub.js
index a0a9c0a9..9f9c1d7f 100644
--- a/src/pubsub.js
+++ b/src/pubsub.js
@@ -199,12 +199,26 @@ class BasicPubSub extends Pubsub {
     }
 
     if (msgs.length) {
-      utils.normalizeInRpcMessages(msgs).forEach((msg) => {
+      msgs.forEach(message => {
+        const msg = utils.normalizeInRpcMessage(message)
         const seqno = utils.msgId(msg.from, msg.seqno)
-        if (!this.seenCache.has(seqno)) {
-          this._processRpcMessage(msg)
-          this.seenCache.put(seqno)
+
+        // Ignore if we've already seen the message
+        if (this.seenCache.has(seqno)) {
+          return
         }
+
+        this.seenCache.put(seqno)
+
+        // Ensure the message is valid before processing it
+        this.validate(message, (err, isValid) => {
+          if (err || !isValid) {
+            this.log('Message could not be validated, dropping it. isValid=%s', isValid, err)
+            return
+          }
+
+          this._processRpcMessage(msg)
+        })
       })
     }
     this._handleRpcControl(peer, rpc)
diff --git a/test/gossip.js b/test/gossip.js
index ffed3f39..53abc1a1 100644
--- a/test/gossip.js
+++ b/test/gossip.js
@@ -3,6 +3,7 @@
 
 const { expect } = require('chai')
 const sinon = require('sinon')
+const promisify = require('promisify-es6')
 
 const { GossipSubDhi } = require('../src/constants')
 const {
@@ -48,7 +49,7 @@ describe('gossip', () => {
     // set spy
     sinon.spy(nodeA.gs, 'log')
 
-    nodeA.gs.publish(topic, Buffer.from('hey'))
+    await promisify(nodeA.gs.publish, { context: nodeA.gs })(topic, Buffer.from('hey'))
     await new Promise((resolve) => nodeA.gs.once('gossipsub:heartbeat', resolve))
     expect(nodeA.gs.log.callCount).to.be.gt(1)
     nodeA.gs.log.getCalls()
@@ -88,8 +89,8 @@ describe('gossip', () => {
 
     // manually add control message to be sent to peerB
     nodeA.gs.control.set(peerB, { graft: [{ topicID: topic }] })
-    nodeA.gs.publish(topic, Buffer.from('hey'))
-    await new Promise((resolve) => setTimeout(resolve, 500))
+    await promisify(nodeA.gs.publish, { context: nodeA.gs })(topic, Buffer.from('hey'))
+    await new Promise((resolve) => nodeA.gs.once('gossipsub:heartbeat', resolve))
     expect(nodeB.gs.log.callCount).to.be.gt(1)
     // expect control message to be sent alongside published message
     const call = nodeB.gs.log.getCalls().find((call) => call.args[0] === 'GRAFT: Add mesh link from %s in %s')
diff --git a/test/pubsub.spec.js b/test/pubsub.spec.js
new file mode 100644
index 00000000..127c1aac
--- /dev/null
+++ b/test/pubsub.spec.js
@@ -0,0 +1,143 @@
+'use strict'
+/* eslint-env mocha */
+/* eslint max-nested-callbacks: ["error", 5] */
+
+const chai = require('chai')
+chai.use(require('dirty-chai'))
+const expect = chai.expect
+const sinon = require('sinon')
+const { utils } = require('libp2p-pubsub')
+const promisify = require('promisify-es6')
+const {
+  createNode,
+  startNode,
+  stopNode
+} = require('./utils')
+
+describe('Pubsub', () => {
+  let nodeA
+  let gossipsub
+  before(async () => {
+    nodeA = await createNode('/ip4/127.0.0.1/tcp/0')
+    gossipsub = nodeA.gs
+    await startNode(nodeA)
+    await startNode(gossipsub)
+  })
+  after(async () => {
+    await stopNode(gossipsub)
+    await stopNode(nodeA)
+  })
+  afterEach(() => {
+    sinon.restore()
+  })
+
+  describe('publish', () => {
+    it('should sign messages on publish', (done) => {
+      sinon.spy(nodeA.gs, '_publish')
+
+      gossipsub.publish('signing-topic', Buffer.from('hello'), (err) => {
+        expect(err).to.not.exist()
+
+        // Get the first message sent to _publish, and validate it
+        const signedMessage = gossipsub._publish.getCall(0).lastArg[0]
+        gossipsub.validate(signedMessage, (err, isValid) => {
+          expect(err).to.not.exist()
+          expect(isValid).to.eql(true)
+          done()
+        })
+      })
+    })
+  })
+
+  describe('validate', () => {
+    it('should drop unsigned messages', () => {
+      sinon.spy(gossipsub, '_processRpcMessage')
+      sinon.spy(gossipsub, 'validate')
+      sinon.spy(gossipsub, 'log')
+      sinon.stub(gossipsub.peers, 'get').returns({})
+
+      const topic = 'my-topic'
+      const rpc = {
+        subscriptions: [],
+        msgs: [{
+          from: gossipsub.peerId.id,
+          data: Buffer.from('an unsigned message'),
+          seqno: utils.randomSeqno(),
+          topicIDs: [topic]
+        }]
+      }
+
+      gossipsub._onRpc('QmAnotherPeer', rpc)
+
+      return new Promise(resolve => setTimeout(() => {
+        const dropLogs = gossipsub.log.getCalls().filter((call) => call.args[0].match(/dropping it/gi))
+        expect(gossipsub.validate.callCount).to.eql(1)
+        expect(gossipsub._processRpcMessage.called).to.eql(false)
+        expect(dropLogs).to.have.length(1)
+        resolve()
+      }, 500))
+    })
+
+    it('should not drop signed messages', async () => {
+      sinon.spy(gossipsub, '_processRpcMessage')
+      sinon.spy(gossipsub, 'validate')
+      sinon.spy(gossipsub, 'log')
+      sinon.stub(gossipsub.peers, 'get').returns({})
+
+      const topic = 'my-topic'
+      const signedMessage = await promisify(gossipsub._buildMessage, {
+        context: gossipsub
+      })({
+        from: gossipsub.peerId.id,
+        data: Buffer.from('an unsigned message'),
+        seqno: utils.randomSeqno(),
+        topicIDs: [topic]
+      })
+
+      const rpc = {
+        subscriptions: [],
+        msgs: [signedMessage]
+      }
+
+      gossipsub._onRpc('QmAnotherPeer', rpc)
+
+      return new Promise(resolve => setTimeout(() => {
+        const dropLogs = gossipsub.log.getCalls().filter((call) => call.args[0].match(/dropping it/gi))
+        expect(gossipsub.validate.callCount).to.eql(1)
+        expect(gossipsub._processRpcMessage.callCount).to.eql(1)
+        expect(dropLogs).to.be.empty()
+        resolve()
+      }, 500))
+    })
+
+    it('should not drop unsigned messages if strict signing is disabled', () => {
+      sinon.spy(gossipsub, '_processRpcMessage')
+      sinon.spy(gossipsub, 'validate')
+      sinon.spy(gossipsub, 'log')
+      sinon.stub(gossipsub.peers, 'get').returns({})
+      // Disable strict signing
+      sinon.stub(gossipsub, 'strictSigning').value(false)
+
+      const topic = 'my-topic'
+      const rpc = {
+        subscriptions: [],
+        msgs: [{
+          from: gossipsub.peerId.id,
+          data: Buffer.from('an unsigned message'),
+          seqno: utils.randomSeqno(),
+          topicIDs: [topic]
+        }]
+      }
+
+      gossipsub._onRpc('QmAnotherPeer', rpc)
+
+      return new Promise(resolve => setTimeout(() => {
+        const dropLogs = gossipsub.log.getCalls().filter((call) => call.args[0].match(/dropping it/gi))
+        expect(gossipsub.validate.callCount).to.eql(1)
+        expect(gossipsub._processRpcMessage.callCount).to.eql(1)
+        expect(dropLogs).to.be.empty()
+        resolve()
+      }, 500))
+    })
+  })
+})