diff --git a/packages/backend/package.json b/packages/backend/package.json
index c07f31c777..b80956e5bc 100644
--- a/packages/backend/package.json
+++ b/packages/backend/package.json
@@ -79,7 +79,7 @@
 		"@fastify/multipart": "8.1.0",
 		"@fastify/static": "6.12.0",
 		"@fastify/view": "8.2.0",
-		"@misskey-dev/node-http-message-signatures": "0.0.0-alpha.7",
+		"@misskey-dev/node-http-message-signatures": "0.0.0-alpha.10",
 		"@misskey-dev/sharp-read-bmp": "1.2.0",
 		"@misskey-dev/summaly": "5.0.3",
 		"@nestjs/common": "10.3.3",
diff --git a/packages/backend/src/server/ActivityPubServerService.ts b/packages/backend/src/server/ActivityPubServerService.ts
index 269bc3fb11..204b9e7aa7 100644
--- a/packages/backend/src/server/ActivityPubServerService.ts
+++ b/packages/backend/src/server/ActivityPubServerService.ts
@@ -101,7 +101,7 @@ export class ActivityPubServerService {
 
 	@bindThis
 	private inbox(request: FastifyRequest, reply: FastifyReply) {
-		let signature;
+		let signature: ReturnType<typeof parseRequestSignature>;
 
 		const verifyDigest = verifyDigestHeader(request.raw, request.rawBody || '', true);
 		if (!verifyDigest) {
@@ -116,11 +116,6 @@ export class ActivityPubServerService {
 			return;
 		}
 
-		if (!signature) {
-			reply.code(401);
-			return;
-		}
-
 		if (signature.value.params.headers.indexOf('host') === -1
 			|| request.headers.host !== this.config.host) {
 			// Host not specified or not match.
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index b989c05254..2d2d6a23d1 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -111,8 +111,8 @@ importers:
         specifier: 8.2.0
         version: 8.2.0
       '@misskey-dev/node-http-message-signatures':
-        specifier: 0.0.0-alpha.7
-        version: 0.0.0-alpha.7
+        specifier: 0.0.0-alpha.10
+        version: 0.0.0-alpha.10
       '@misskey-dev/sharp-read-bmp':
         specifier: 1.2.0
         version: 1.2.0
@@ -4750,8 +4750,8 @@ packages:
       eslint-plugin-import: 2.29.1(@typescript-eslint/parser@7.1.0)(eslint@8.57.0)
     dev: true
 
-  /@misskey-dev/node-http-message-signatures@0.0.0-alpha.7:
-    resolution: {integrity: sha512-iM1nZ3YT+G4AEhbUnsK7PqnMY9MjBP5JomQAgi2OyxDtZ/wBpgLP6MCVz3ElCqZ8NQS1f+c4E1m6/dSN8MtU9Q==}
+  /@misskey-dev/node-http-message-signatures@0.0.0-alpha.10:
+    resolution: {integrity: sha512-4weLJVBm06bx4fLJHL9YtKXQ8ofKSNDI4UAaoI0JkzbbU8pyJHK4LFGfERrpUX9C+WsvSwVFZAgAzOxFwJ7z2w==}
     dev: false
 
   /@misskey-dev/sharp-read-bmp@1.2.0: