diff --git a/packages/backend/src/core/activitypub/misc/contexts.ts b/packages/backend/src/core/activitypub/misc/contexts.ts
index feb8c42c56..fc4e3e3bef 100644
--- a/packages/backend/src/core/activitypub/misc/contexts.ts
+++ b/packages/backend/src/core/activitypub/misc/contexts.ts
@@ -134,6 +134,7 @@ const security_v1 = {
 		'privateKey': { '@id': 'sec:privateKey', '@type': '@id' },
 		'privateKeyPem': 'sec:privateKeyPem',
 		'publicKey': { '@id': 'sec:publicKey', '@type': '@id' },
+		'additionalPublicKeys': { '@id': 'sec:publicKey', '@type': '@id' },
 		'publicKeyBase58': 'sec:publicKeyBase58',
 		'publicKeyPem': 'sec:publicKeyPem',
 		'publicKeyWif': 'sec:publicKeyWif',