diff --git a/src/main/kotlin/dev/usbharu/hideout/activitypub/domain/exception/HttpSignatureUnauthorizedException.kt b/src/main/kotlin/dev/usbharu/hideout/activitypub/domain/exception/HttpSignatureUnauthorizedException.kt
new file mode 100644
index 00000000..9abccec6
--- /dev/null
+++ b/src/main/kotlin/dev/usbharu/hideout/activitypub/domain/exception/HttpSignatureUnauthorizedException.kt
@@ -0,0 +1,14 @@
+package dev.usbharu.hideout.activitypub.domain.exception
+
+class HttpSignatureUnauthorizedException : RuntimeException {
+    constructor() : super()
+    constructor(message: String?) : super(message)
+    constructor(message: String?, cause: Throwable?) : super(message, cause)
+    constructor(cause: Throwable?) : super(cause)
+    constructor(message: String?, cause: Throwable?, enableSuppression: Boolean, writableStackTrace: Boolean) : super(
+        message,
+        cause,
+        enableSuppression,
+        writableStackTrace
+    )
+}
diff --git a/src/main/kotlin/dev/usbharu/hideout/activitypub/service/tmp/AbstractActivityPubProcessor.kt b/src/main/kotlin/dev/usbharu/hideout/activitypub/service/tmp/AbstractActivityPubProcessor.kt
index 6a3aba7e..c5d927c9 100644
--- a/src/main/kotlin/dev/usbharu/hideout/activitypub/service/tmp/AbstractActivityPubProcessor.kt
+++ b/src/main/kotlin/dev/usbharu/hideout/activitypub/service/tmp/AbstractActivityPubProcessor.kt
@@ -2,14 +2,21 @@ package dev.usbharu.hideout.activitypub.service.tmp
 
 import dev.usbharu.hideout.activitypub.domain.exception.ActivityPubProcessException
 import dev.usbharu.hideout.activitypub.domain.exception.FailedProcessException
+import dev.usbharu.hideout.activitypub.domain.exception.HttpSignatureUnauthorizedException
 import dev.usbharu.hideout.activitypub.domain.model.objects.Object
 import dev.usbharu.hideout.application.external.Transaction
 import org.slf4j.LoggerFactory
 
-abstract class AbstractActivityPubProcessor<T : Object>(val transaction: Transaction) : ActivityPubProcessor<T> {
+abstract class AbstractActivityPubProcessor<T : Object>(
+    private val transaction: Transaction,
+    private val allowUnauthorized: Boolean = false
+) : ActivityPubProcessor<T> {
     private val logger = LoggerFactory.getLogger(this::class.java)
 
     override suspend fun process(activity: ActivityPubProcessContext<T>) {
+        if (activity.isAuthorized.not() && allowUnauthorized.not()) {
+            throw HttpSignatureUnauthorizedException()
+        }
         logger.info("START ActivityPub process")
         try {
             transaction.transaction {
diff --git a/src/main/kotlin/dev/usbharu/hideout/activitypub/service/tmp/impl/CreateActivityProcessor.kt b/src/main/kotlin/dev/usbharu/hideout/activitypub/service/tmp/impl/CreateActivityProcessor.kt
new file mode 100644
index 00000000..60918d01
--- /dev/null
+++ b/src/main/kotlin/dev/usbharu/hideout/activitypub/service/tmp/impl/CreateActivityProcessor.kt
@@ -0,0 +1,22 @@
+package dev.usbharu.hideout.activitypub.service.tmp.impl
+
+import dev.usbharu.hideout.activitypub.domain.model.Create
+import dev.usbharu.hideout.activitypub.domain.model.Note
+import dev.usbharu.hideout.activitypub.service.common.ActivityType
+import dev.usbharu.hideout.activitypub.service.objects.note.APNoteService
+import dev.usbharu.hideout.activitypub.service.tmp.AbstractActivityPubProcessor
+import dev.usbharu.hideout.activitypub.service.tmp.ActivityPubProcessContext
+import dev.usbharu.hideout.application.external.Transaction
+import org.springframework.stereotype.Service
+
+@Service
+class CreateActivityProcessor(transaction: Transaction, private val apNoteService: APNoteService) :
+    AbstractActivityPubProcessor<Create>(transaction, false) {
+    override suspend fun internalProcess(activity: ActivityPubProcessContext<Create>) {
+        apNoteService.fetchNote(activity.activity.`object` as Note)
+    }
+
+    override fun isSupported(activityType: ActivityType): Boolean = activityType == ActivityType.Create
+
+    override fun type(): Class<Create> = Create::class.java
+}