diff --git a/packages/backend/src/core/activitypub/ApRendererService.ts b/packages/backend/src/core/activitypub/ApRendererService.ts
index 66322f6870..66a15b2d18 100644
--- a/packages/backend/src/core/activitypub/ApRendererService.ts
+++ b/packages/backend/src/core/activitypub/ApRendererService.ts
@@ -501,7 +501,7 @@ export class ApRendererService {
 			discoverable: user.isExplorable,
 			publicKey: this.renderKey(user, keypair.publicKey, '#main-key'),
 			additionalPublicKeys: [
-				...(keypair.ed25519PublicKey ? [this.renderKey(user, keypair.ed25519PublicKey, '#ed25519-key', { type: keypair.ed25519SignatureAlgorithm!, signatureValue: keypair.ed25519PublicKeySignature! })] : []),
+				...(keypair.ed25519PublicKey ? [this.renderKey(user, keypair.ed25519PublicKey, '#ed25519-key', { signatureAlgorithm: keypair.ed25519SignatureAlgorithm!, signatureValue: keypair.ed25519PublicKeySignature! })] : []),
 			],
 			isCat: user.isCat,
 			attachment: attachment.length ? attachment : undefined,
@@ -649,6 +649,7 @@ export class ApRendererService {
 					'_misskey_votes': 'misskey:_misskey_votes',
 					'_misskey_summary': 'misskey:_misskey_summary',
 					'isCat': 'misskey:isCat',
+					additionalPublicKeys: 'misskey:additionalPublicKeys',
 					// vcard
 					vcard: 'http://www.w3.org/2006/vcard/ns#',
 				},
diff --git a/packages/backend/src/core/activitypub/models/ApPersonService.ts b/packages/backend/src/core/activitypub/models/ApPersonService.ts
index 4c1f79e1b1..36fad4c759 100644
--- a/packages/backend/src/core/activitypub/models/ApPersonService.ts
+++ b/packages/backend/src/core/activitypub/models/ApPersonService.ts
@@ -216,8 +216,8 @@ export class ApPersonService implements OnModuleInit {
 				if (!key.signature) {
 					throw new Error('invalid Actor: additionalPublicKeys.signature is not set');
 				}
-				if (typeof key.signature.type !== 'string') {
-					throw new Error('invalid Actor: additionalPublicKeys.signature.type is not a string');
+				if (typeof key.signature.signatureAlgorithm !== 'string') {
+					throw new Error('invalid Actor: additionalPublicKeys.signature.signatureAlgorithm is not a string');
 				}
 				if (typeof key.signature.signatureValue !== 'string') {
 					throw new Error('invalid Actor: additionalPublicKeys.signature.signatureValue is not a string');
@@ -397,8 +397,8 @@ export class ApPersonService implements OnModuleInit {
 					if (person.additionalPublicKeys) {
 						for (const key of person.additionalPublicKeys) {
 							if (
-								key.signature && key.signature.type && key.signature.signatureValue &&
-								verify(key.signature.type, Buffer.from(key.publicKeyPem), person.publicKey.publicKeyPem, Buffer.from(key.signature.signatureValue, 'base64'))
+								key.signature && key.signature.signatureAlgorithm && key.signature.signatureValue &&
+								verify(key.signature.signatureAlgorithm, Buffer.from(key.publicKeyPem), person.publicKey.publicKeyPem, Buffer.from(key.signature.signatureValue, 'base64'))
 							) {
 								await transactionalEntityManager.save(new MiUserPublickey({
 									keyId: key.id,
@@ -564,8 +564,8 @@ export class ApPersonService implements OnModuleInit {
 			if (person.additionalPublicKeys) {
 				for (const key of person.additionalPublicKeys) {
 					if (
-						key.signature && key.signature.type && key.signature.signatureValue &&
-						verify(key.signature.type, Buffer.from(key.publicKeyPem), person.publicKey.publicKeyPem, Buffer.from(key.signature.signatureValue, 'base64'))
+						key.signature && key.signature.signatureAlgorithm && key.signature.signatureValue &&
+						verify(key.signature.signatureAlgorithm, Buffer.from(key.publicKeyPem), person.publicKey.publicKeyPem, Buffer.from(key.signature.signatureValue, 'base64'))
 					) {
 						await this.userPublickeysRepository.update({ keyId: key.id }, {
 							userId: exist.id,
diff --git a/packages/backend/src/core/activitypub/type.ts b/packages/backend/src/core/activitypub/type.ts
index 72d383442e..ff0d340b6b 100644
--- a/packages/backend/src/core/activitypub/type.ts
+++ b/packages/backend/src/core/activitypub/type.ts
@@ -241,7 +241,7 @@ export interface IKey extends IObject {
 	 * Signature of publicKeyPem, signed by root privateKey (for additionalPublicKey)
 	 */
 	signature?: {
-		type: string;
+		signatureAlgorithm: string;
 		signatureValue: string
 	};
 }