diff --git a/keystore/binder/android/security/keystore/IKeystoreService.aidl b/keystore/binder/android/security/keystore/IKeystoreService.aidl
index ea1e0f4..348964f 100644
--- a/keystore/binder/android/security/keystore/IKeystoreService.aidl
+++ b/keystore/binder/android/security/keystore/IKeystoreService.aidl
@@ -75,5 +75,5 @@
     int cancelConfirmationPrompt(IBinder listener);
     boolean isConfirmationPromptSupported();
     int onKeyguardVisibilityChanged(in boolean isShowing, in int userId);
-    int listUidsOfAuthBoundKeys(out int[] uids);
+    int listUidsOfAuthBoundKeys(out @utf8InCpp List<String> uids);
 }
diff --git a/keystore/key_store_service.cpp b/keystore/key_store_service.cpp
index 2f17848..a7fcd38 100644
--- a/keystore/key_store_service.cpp
+++ b/keystore/key_store_service.cpp
@@ -281,7 +281,7 @@
  * if the password/pin is removed. Only allowed to be called by system.
  * The output is bound by the initial size of uidsOut to be compatible with Java.
  */
-Status KeyStoreService::listUidsOfAuthBoundKeys(::std::vector<int32_t>* uidsOut,
+Status KeyStoreService::listUidsOfAuthBoundKeys(std::vector<std::string>* uidsOut,
                                                 int32_t* aidl_return) {
     const int32_t callingUid = IPCThreadState::self()->getCallingUid();
     const int32_t userId = get_user_id(callingUid);
@@ -312,14 +312,11 @@
         return Status::fromServiceSpecificError(static_cast<int32_t>(rc));
     }
 
-    auto it = uidsOut->begin();
     for (LockedKeyBlobEntry& entry : internal_matches) {
-        if (it == uidsOut->end()) {
-            ALOGW("Maximum number (%d) of auth bound uids found, truncating remainder",
-                  static_cast<int32_t>(uidsOut->capacity()));
-            break;
-        }
-        if (std::find(uidsOut->begin(), it, entry->uid()) != it) {
+        // Need to store uids as a list of strings because integer list output
+        // parameters is not supported in aidl-cpp.
+        std::string entryUid = std::to_string(entry->uid());
+        if (std::find(uidsOut->begin(), uidsOut->end(), entryUid) != uidsOut->end()) {
             // uid already in list, skip
             continue;
         }
@@ -331,7 +328,7 @@
         }
 
         if (blob && blob.isEncrypted()) {
-            *it++ = entry->uid();
+            uidsOut->push_back(entryUid);
         } else if (charBlob) {
             auto [success, hwEnforced, swEnforced] = charBlob.getKeyCharacteristics();
             if (!success) {
@@ -340,7 +337,7 @@
             }
             if (hwEnforced.Contains(TAG_USER_SECURE_ID) ||
                 swEnforced.Contains(TAG_USER_SECURE_ID)) {
-                *it++ = entry->uid();
+                uidsOut->push_back(entryUid);
             }
         }
     }
diff --git a/keystore/key_store_service.h b/keystore/key_store_service.h
index 5a3586f..2171213 100644
--- a/keystore/key_store_service.h
+++ b/keystore/key_store_service.h
@@ -61,7 +61,7 @@
                                     int32_t* _aidl_return) override;
     ::android::binder::Status list(const ::android::String16& namePrefix, int32_t uid,
                                    ::std::vector<::android::String16>* _aidl_return) override;
-    ::android::binder::Status listUidsOfAuthBoundKeys(::std::vector<int32_t>* uids,
+    ::android::binder::Status listUidsOfAuthBoundKeys(std::vector<::std::string>* uids,
                                                       int32_t* _aidl_return) override;
 
     ::android::binder::Status reset(int32_t* _aidl_return) override;
diff --git a/keystore/keystore_cli_v2.cpp b/keystore/keystore_cli_v2.cpp
index 0500da2..b46b221 100644
--- a/keystore/keystore_cli_v2.cpp
+++ b/keystore/keystore_cli_v2.cpp
@@ -384,7 +384,7 @@
         return 1;
     }
     int32_t aidl_return;
-    ::std::vector<int32_t> uids(100);
+    ::std::vector<::std::string> uids;
     android::binder::Status status = service->listUidsOfAuthBoundKeys(&uids, &aidl_return);
     if (!status.isOk()) {
         fprintf(stderr, "Requesting uids of auth bound keys failed with error %s.\n",
@@ -397,8 +397,7 @@
     }
     printf("Apps with auth bound keys:\n");
     for (auto i = uids.begin(); i != uids.end(); ++i) {
-        if (*i == 0) break;
-        printf("%d\n", *i);
+        printf("%s\n", i->c_str());
     }
     return 0;
 }