diff --git a/src/stage.js b/src/stage.js
index 0e73f92..aac2418 100644
--- a/src/stage.js
+++ b/src/stage.js
@@ -55,7 +55,7 @@ async function derive (factor, params, key) {
     result.params = Promise.resolve(params)
 
     const output = await result.output()
-    result.output = Promise.resolve(output)
+    result.output = () => Promise.resolve(output)
   }
 
   return () => Promise.resolve(result)
diff --git a/test/features/stage.js b/test/features/stage.js
index 35effcb..894932d 100644
--- a/test/features/stage.js
+++ b/test/features/stage.js
@@ -51,13 +51,13 @@ suite('stage', () => {
     const json = JSON.parse(Buffer.from(decrypted).toString())
     const code = json.code
 
-    const password = await mfkdf.stage.factor.derive(mfkdf.derive.factors.password('password'), setup.policy.factors[0].params)
-    const hmacsha1 = await mfkdf.stage.factor.derive(mfkdf.derive.factors.hmacsha1(response), setup.policy.factors[1].params)
-    const hotp = await mfkdf.stage.factor.derive(mfkdf.derive.factors.hotp(365287), setup.policy.factors[2].params)
-    const ooba = await mfkdf.stage.factor.derive(mfkdf.derive.factors.ooba(code), setup.policy.factors[3].params)
-    const question = await mfkdf.stage.factor.derive(mfkdf.derive.factors.question('fido'), setup.policy.factors[4].params)
-    const totp = await mfkdf.stage.factor.derive(mfkdf.derive.factors.totp(528258, { time: 1650430943604 }), setup.policy.factors[5].params)
-    const uuid = await mfkdf.stage.factor.derive(mfkdf.derive.factors.uuid('9b1deb4d-3b7d-4bad-9bdd-2b0d7b3dcb6d'), setup.policy.factors[6].params)
+    const password = await mfkdf.stage.factor.derive(mfkdf.derive.factors.password('password'), setup.policy.factors[0].params, setup.key)
+    const hmacsha1 = await mfkdf.stage.factor.derive(mfkdf.derive.factors.hmacsha1(response), setup.policy.factors[1].params, setup.key)
+    const hotp = await mfkdf.stage.factor.derive(mfkdf.derive.factors.hotp(365287), setup.policy.factors[2].params, setup.key)
+    const ooba = await mfkdf.stage.factor.derive(mfkdf.derive.factors.ooba(code), setup.policy.factors[3].params, setup.key)
+    const question = await mfkdf.stage.factor.derive(mfkdf.derive.factors.question('fido'), setup.policy.factors[4].params, setup.key)
+    const totp = await mfkdf.stage.factor.derive(mfkdf.derive.factors.totp(528258, { time: 1650430943604 }), setup.policy.factors[5].params, setup.key)
+    const uuid = await mfkdf.stage.factor.derive(mfkdf.derive.factors.uuid('9b1deb4d-3b7d-4bad-9bdd-2b0d7b3dcb6d'), setup.policy.factors[6].params, setup.key)
 
     const derive = await mfkdf.derive.key(setup.policy, {
       password, hmacsha1, hotp, ooba, question, totp, uuid