diff --git a/security/keymint/aidl/android/hardware/security/keymint/IRemotelyProvisionedComponent.aidl b/security/keymint/aidl/android/hardware/security/keymint/IRemotelyProvisionedComponent.aidl
index 1b09e9d..327e4a1 100644
--- a/security/keymint/aidl/android/hardware/security/keymint/IRemotelyProvisionedComponent.aidl
+++ b/security/keymint/aidl/android/hardware/security/keymint/IRemotelyProvisionedComponent.aidl
@@ -165,7 +165,7 @@
      *                protected: bstr .cbor {
      *                    1 : -8,                     // Algorithm : EdDSA
      *                },
-     *                unprotected: bstr .size 0
+     *                unprotected: { },
      *                payload: bstr .cbor SignatureKey,
      *                signature: bstr PureEd25519(.cbor SignatureKeySignatureInput)
      *            ]
@@ -190,7 +190,7 @@
      *                protected: bstr .cbor {
      *                    1 : -8,                     // Algorithm : EdDSA
      *                },
-     *                unprotected: bstr .size 0
+     *                unprotected: { },
      *                payload: bstr .cbor Eek,
      *                signature: bstr PureEd25519(.cbor EekSignatureInput)
      *            ]
@@ -239,7 +239,7 @@
      *                protected : bstr .cbor {
      *                    1 : 5,                           // Algorithm : HMAC-256
      *                },
-     *                unprotected : bstr .size 0,
+     *                unprotected : { },
      *                // Payload is PublicKeys from keysToSign argument, in provided order.
      *                payload: bstr .cbor [ * PublicKey ],
      *                tag: bstr
diff --git a/security/keymint/aidl/android/hardware/security/keymint/MacedPublicKey.aidl b/security/keymint/aidl/android/hardware/security/keymint/MacedPublicKey.aidl
index da85a50..cb5492d 100644
--- a/security/keymint/aidl/android/hardware/security/keymint/MacedPublicKey.aidl
+++ b/security/keymint/aidl/android/hardware/security/keymint/MacedPublicKey.aidl
@@ -29,7 +29,7 @@
      *
      *     MacedPublicKey = [                     // COSE_Mac0
      *         protected: bstr .cbor { 1 : 5},    // Algorithm : HMAC-256
-     *         unprotected: bstr .size 0,
+     *         unprotected: { },
      *         payload : bstr .cbor PublicKey,
      *         tag : bstr HMAC-256(K_mac, MAC_structure)
      *     ]
diff --git a/security/keymint/aidl/android/hardware/security/keymint/ProtectedData.aidl b/security/keymint/aidl/android/hardware/security/keymint/ProtectedData.aidl
index 1ec3bf0..438505e 100644
--- a/security/keymint/aidl/android/hardware/security/keymint/ProtectedData.aidl
+++ b/security/keymint/aidl/android/hardware/security/keymint/ProtectedData.aidl
@@ -80,7 +80,7 @@
      *         bstr .cbor {                    // Protected params
      *             1 : -8,                     // Algorithm : EdDSA
      *         },
-     *         bstr .size 0,                   // Unprotected params
+     *         { },                            // Unprotected params
      *         bstr .size 32,                  // MAC key
      *         bstr PureEd25519(DK_priv, .cbor SignedMac_structure)
      *     ]
@@ -127,7 +127,7 @@
      *         protected: bstr .cbor {
      *             1 : -8,                    // Algorithm : EdDSA
      *         },
-     *         unprotected: bstr .size 0,
+     *         unprotected: { },
      *         payload: bstr .cbor BccPayload,
      *         // First entry in the chain is signed by DK_pub, the others are each signed by their
      *         // immediate predecessor.  See RFC 8032 for signature representation.
diff --git a/security/keymint/aidl/default/RemotelyProvisionedComponent.cpp b/security/keymint/aidl/default/RemotelyProvisionedComponent.cpp
index 2373b26..749f0bc 100644
--- a/security/keymint/aidl/default/RemotelyProvisionedComponent.cpp
+++ b/security/keymint/aidl/default/RemotelyProvisionedComponent.cpp
@@ -156,7 +156,7 @@
         }
 
         auto protectedParms = macedKeyItem->asArray()->get(kCoseMac0ProtectedParams)->asBstr();
-        auto unprotectedParms = macedKeyItem->asArray()->get(kCoseMac0UnprotectedParams)->asBstr();
+        auto unprotectedParms = macedKeyItem->asArray()->get(kCoseMac0UnprotectedParams)->asMap();
         auto payload = macedKeyItem->asArray()->get(kCoseMac0Payload)->asBstr();
         auto tag = macedKeyItem->asArray()->get(kCoseMac0Tag)->asBstr();
         if (!protectedParms || !unprotectedParms || !payload || !tag) {
diff --git a/security/keymint/aidl/vts/functional/VtsRemotelyProvisionedComponentTests.cpp b/security/keymint/aidl/vts/functional/VtsRemotelyProvisionedComponentTests.cpp
index db53a8f..50e6cce 100644
--- a/security/keymint/aidl/vts/functional/VtsRemotelyProvisionedComponentTests.cpp
+++ b/security/keymint/aidl/vts/functional/VtsRemotelyProvisionedComponentTests.cpp
@@ -97,9 +97,9 @@
     ASSERT_NE(protParms, nullptr);
     ASSERT_EQ(cppbor::prettyPrint(protParms->value()), "{\n  1 : 5,\n}");
 
-    auto unprotParms = coseMac0->asArray()->get(kCoseMac0UnprotectedParams)->asBstr();
+    auto unprotParms = coseMac0->asArray()->get(kCoseMac0UnprotectedParams)->asMap();
     ASSERT_NE(unprotParms, nullptr);
-    ASSERT_EQ(unprotParms->value().size(), 0);
+    ASSERT_EQ(unprotParms->size(), 0);
 
     auto payload = coseMac0->asArray()->get(kCoseMac0Payload)->asBstr();
     ASSERT_NE(payload, nullptr);
@@ -150,9 +150,9 @@
     ASSERT_NE(protParms, nullptr);
     ASSERT_EQ(cppbor::prettyPrint(protParms->value()), "{\n  1 : 5,\n}");
 
-    auto unprotParms = coseMac0->asArray()->get(kCoseMac0UnprotectedParams)->asBstr();
+    auto unprotParms = coseMac0->asArray()->get(kCoseMac0UnprotectedParams)->asMap();
     ASSERT_NE(unprotParms, nullptr);
-    ASSERT_EQ(unprotParms->value().size(), 0);
+    ASSERT_EQ(unprotParms->size(), 0);
 
     auto payload = coseMac0->asArray()->get(kCoseMac0Payload)->asBstr();
     ASSERT_NE(payload, nullptr);
@@ -279,7 +279,7 @@
                                          .add(ALGORITHM, HMAC_256)
                                          .canonicalize()
                                          .encode())
-                            .add(cppbor::Bstr())             // unprotected
+                            .add(cppbor::Map())              // unprotected
                             .add(cppbor::Array().encode())   // payload (keysToSign)
                             .add(std::move(keysToSignMac));  // tag
 
@@ -364,7 +364,7 @@
                                          .add(ALGORITHM, HMAC_256)
                                          .canonicalize()
                                          .encode())
-                            .add(cppbor::Bstr())             // unprotected
+                            .add(cppbor::Map())              // unprotected
                             .add(cborKeysToSign_.encode())   // payload
                             .add(std::move(keysToSignMac));  // tag