diff --git a/contracts/Marketplace.sol b/contracts/Marketplace.sol
index 8e3b777..d511095 100644
--- a/contracts/Marketplace.sol
+++ b/contracts/Marketplace.sol
@@ -22,6 +22,7 @@ contract Marketplace is Collateral {
     marketplaceInvariant
   {
     bytes32 id = keccak256(abi.encode(request));
+    require(request.client == msg.sender, "Invalid client address");
     require(request.size > 0, "Invalid size");
     require(requests[id].size == 0, "Request already exists");
     requests[id] = request;
@@ -45,6 +46,7 @@ contract Marketplace is Collateral {
   }
 
   struct Request {
+    address client;
     uint256 duration;
     uint256 size;
     bytes32 contentHash;
diff --git a/test/Marketplace.test.js b/test/Marketplace.test.js
index 6472b16..48c78c7 100644
--- a/test/Marketplace.test.js
+++ b/test/Marketplace.test.js
@@ -5,24 +5,42 @@ const { now, hours } = require("./time")
 const { keccak256, defaultAbiCoder } = ethers.utils
 
 describe("Marketplace", function () {
-  const request = exampleRequest()
-  const offer = { ...exampleOffer(), requestId: requestId(request) }
   const collateral = 100
 
   let marketplace
   let token
-  let accounts
+  let client, host
+  let request, offer
 
   beforeEach(async function () {
+    ;[client, host] = await ethers.getSigners()
+
     const TestToken = await ethers.getContractFactory("TestToken")
     token = await TestToken.deploy()
+    await token.mint(client.address, 1000)
+    await token.mint(host.address, 1000)
+
     const Marketplace = await ethers.getContractFactory("Marketplace")
     marketplace = await Marketplace.deploy(token.address, collateral)
-    accounts = await ethers.getSigners()
-    await token.mint(accounts[0].address, 1000)
+
+    request = exampleRequest()
+    request.client = client.address
+
+    offer = exampleOffer()
+    offer.host = host.address
+    offer.requestId = requestId(request)
   })
 
+  function switchAccount(account) {
+    token = token.connect(account)
+    marketplace = marketplace.connect(account)
+  }
+
   describe("requesting storage", function () {
+    beforeEach(function () {
+      switchAccount(client)
+    })
+
     it("emits event when storage is requested", async function () {
       await token.approve(marketplace.address, request.maxPrice)
       await expect(marketplace.requestStorage(request))
@@ -30,6 +48,14 @@ describe("Marketplace", function () {
         .withArgs(requestId(request), requestToArray(request))
     })
 
+    it("rejects request with invalid client address", async function () {
+      let invalid = { ...request, client: host.address }
+      await token.approve(marketplace.address, invalid.maxPrice)
+      await expect(marketplace.requestStorage(invalid)).to.be.revertedWith(
+        "Invalid client address"
+      )
+    })
+
     it("rejects request with insufficient payment", async function () {
       let insufficient = request.maxPrice - 1
       await token.approve(marketplace.address, insufficient)
@@ -57,8 +83,10 @@ describe("Marketplace", function () {
 
   describe("offering storage", function () {
     beforeEach(async function () {
+      switchAccount(client)
       await token.approve(marketplace.address, request.maxPrice)
       await marketplace.requestStorage(request)
+      switchAccount(host)
       await token.approve(marketplace.address, collateral)
       await marketplace.deposit(collateral)
     })
@@ -114,6 +142,7 @@ function requestId(request) {
   return keccak256(
     defaultAbiCoder.encode(
       [
+        "address",
         "uint256",
         "uint256",
         "bytes32",
@@ -138,6 +167,7 @@ function offerId(offer) {
 
 function requestToArray(request) {
   return [
+    request.client,
     request.duration,
     request.size,
     request.contentHash,
diff --git a/test/examples.js b/test/examples.js
index 88ab615..d400bf4 100644
--- a/test/examples.js
+++ b/test/examples.js
@@ -3,6 +3,7 @@ const { now, hours } = require("./time")
 const { sha256, hexlify, randomBytes } = ethers.utils
 
 const exampleRequest = () => ({
+  client: hexlify(randomBytes(20)),
   duration: 150, // 150 blocks ≈ half an hour
   size: 1 * 1024 * 1024 * 1024, // 1 Gigabyte
   contentHash: sha256("0xdeadbeef"),