diff --git a/ghost/core/core/server/services/members/RequestIntegrityTokenProvider.js b/ghost/core/core/server/services/members/RequestIntegrityTokenProvider.js
index 50baacf5b8..7752185830 100644
--- a/ghost/core/core/server/services/members/RequestIntegrityTokenProvider.js
+++ b/ghost/core/core/server/services/members/RequestIntegrityTokenProvider.js
@@ -7,7 +7,7 @@ class RequestIntegrityTokenProvider {
     /**
      * @param {object} options
      * @param {string} options.themeSecret
-     * @param {number} options.tokenDuration
+     * @param {number} options.tokenDuration - in milliseconds
      */
     constructor(options) {
         this.#themeSecret = options.themeSecret;
@@ -37,12 +37,12 @@ class RequestIntegrityTokenProvider {
             return false;
         }
 
-        const nonce = parts[0];
-        const timestamp = parseInt(parts[1], 10);
+        const timestamp = parseInt(parts[0], 10);
+        const nonce = parts[1];
         const hmacDigest = parts[2];
 
         const hmac = crypto.createHmac('sha256', this.#themeSecret);
-        hmac.update(`${nonce}:${timestamp.toString()}`);
+        hmac.update(`${timestamp.toString()}:${nonce}`);
         const expectedHmac = hmac.digest('hex');
 
         if (expectedHmac !== hmacDigest) {
diff --git a/ghost/core/test/unit/server/services/members/RequestIntegrityTokenProvider.test.js b/ghost/core/test/unit/server/services/members/RequestIntegrityTokenProvider.test.js
new file mode 100644
index 0000000000..e13c0abd5b
--- /dev/null
+++ b/ghost/core/test/unit/server/services/members/RequestIntegrityTokenProvider.test.js
@@ -0,0 +1,70 @@
+const sinon = require('sinon');
+const should = require('should');
+
+const RequestIntegrityTokenProvider = require('../../../../../core/server/services/members/RequestIntegrityTokenProvider');
+
+const tokenProvider = new RequestIntegrityTokenProvider({
+    themeSecret: 'test',
+    tokenDuration: 100
+});
+
+describe('RequestIntegrityTokenProvider', function () {
+    beforeEach(function () {
+        sinon.useFakeTimers(new Date('2021-01-01'));
+    });
+
+    afterEach(function () {
+        sinon.restore();
+    });
+
+    describe('create', function () {
+        it('should create a HMAC digest from the secret', function () {
+            const token = tokenProvider.create();
+
+            token.should.be.a.String();
+            token.split(':').should.be.an.Array().with.lengthOf(3);
+            const [timestamp, nonce, digest] = token.split(':');
+
+            timestamp.should.equal((new Date('2021-01-01').valueOf() + 100).toString());
+
+            nonce.should.match(/[0-9a-f]{16}/);
+
+            digest.should.be.a.String().with.lengthOf(64);
+        });
+    });
+
+    describe('validate', function () {
+        it('should verify a HMAC digest from the secret', function () {
+            const token = tokenProvider.create();
+            const result = tokenProvider.validate(token);
+
+            result.should.be.true();
+        });
+
+        it('should fail to verify an expired token', function () {
+            const token = tokenProvider.create();
+            sinon.clock.tick(101);
+            const result = tokenProvider.validate(token);
+
+            result.should.be.false();
+        });
+
+        it('should fail to verify a malformed token', function () {
+            const token = 'invalid_token';
+            const result = tokenProvider.validate(token);
+
+            result.should.be.false();
+        });
+
+        it('should fail to verify a token with an invalid signature', function () {
+            const token = tokenProvider.create();
+            const [timestamp, nonce] = token.split(':');
+            const invalidDigest = 'a'.repeat(64); // Create an invalid digest
+            const invalidToken = `${timestamp}:${nonce}:${invalidDigest}`;
+
+            const result = tokenProvider.validate(invalidToken);
+
+            result.should.be.false();
+        });
+    });
+});