diff --git a/lib/fastifySession.js b/lib/fastifySession.js
index e624882..9e43429 100644
--- a/lib/fastifySession.js
+++ b/lib/fastifySession.js
@@ -203,14 +203,16 @@ function fastifySession (fastify, options, next) {
   }
 
   function checkOptions (options) {
-    if (!options.secret) {
-      return new Error('the secret option is required!')
-    }
-    if (typeof options.secret === 'string' && options.secret.length < 32) {
-      return new Error('the secret must have length 32 or greater')
-    }
-    if (Array.isArray(options.secret) && options.secret.length === 0) {
-      return new Error('at least one secret is required')
+    if (typeof options.secret === 'string') {
+      if (options.secret.length < 32) {
+        return new Error('the secret must have length 32 or greater')
+      }
+    } else if (Array.isArray(options.secret)) {
+      if (options.secret.length === 0) {
+        return new Error('at least one secret is required')
+      }
+    } else if (!(options.secret && typeof options.secret.sign === 'function' && typeof options.secret.unsign === 'function')) {
+      return new Error('the secret option is required, and must be a String, Array of Strings, or a signer object with .sign and .unsign methods')
     }
   }
 
diff --git a/test/fastifySession.checkOptions.test.js b/test/fastifySession.checkOptions.test.js
index d11868c..a897140 100644
--- a/test/fastifySession.checkOptions.test.js
+++ b/test/fastifySession.checkOptions.test.js
@@ -14,7 +14,7 @@ test('fastifySession.checkOptions: register should fail if no secret is specifie
   fastify.register(fastifyCookie)
   fastify.register(fastifySession, options)
 
-  await t.rejects(fastify.ready(), new Error('the secret option is required!'))
+  await t.rejects(fastify.ready(), new Error('the secret option is required, and must be a String, Array of Strings, or a signer object with .sign and .unsign methods'))
 })
 
 test('fastifySession.checkOptions: register should succeed if secret with 32 characters is specified', async t => {
@@ -73,3 +73,39 @@ test('fastifySession.checkOptions: register should fail if no secret is present
   fastify.register(fastifySession, { secret: [] })
   await t.rejects(fastify.ready(), new Error('at least one secret is required'))
 })
+
+test('fastifySession.checkOptions: register should fail if a Buffer is passed', async t => {
+  t.plan(1)
+  const fastify = Fastify()
+
+  fastify.register(fastifyCookie)
+  fastify.register(fastifySession, { secret: crypto.randomBytes(32) })
+  await t.rejects(fastify.ready(), new Error('the secret option is required, and must be a String, Array of Strings, or a signer object with .sign and .unsign methods'))
+})
+
+test('fastifySession.checkOptions: register should fail if a signer missing unsign is passed', async t => {
+  t.plan(1)
+  const fastify = Fastify()
+
+  const invalidSigner = {
+    sign: (x) => x,
+    unsign: true
+  }
+
+  fastify.register(fastifyCookie)
+  fastify.register(fastifySession, { secret: invalidSigner })
+  await t.rejects(fastify.ready(), new Error('the secret option is required, and must be a String, Array of Strings, or a signer object with .sign and .unsign methods'))
+})
+
+test('fastifySession.checkOptions: register should fail if a signer missing sign is passed', async t => {
+  t.plan(1)
+  const fastify = Fastify()
+
+  const invalidSigner = {
+    unsign: (x) => true
+  }
+
+  fastify.register(fastifyCookie)
+  fastify.register(fastifySession, { secret: invalidSigner })
+  await t.rejects(fastify.ready(), new Error('the secret option is required, and must be a String, Array of Strings, or a signer object with .sign and .unsign methods'))
+})