diff --git a/src/CryptoEngine/AbstractCryptoEngine.ts b/src/CryptoEngine/AbstractCryptoEngine.ts
index 8915b5a9a..89aa1c1a2 100644
--- a/src/CryptoEngine/AbstractCryptoEngine.ts
+++ b/src/CryptoEngine/AbstractCryptoEngine.ts
@@ -63,6 +63,7 @@ export abstract class AbstractCryptoEngine implements type.ICryptoEngine {
   }
 
   public generateKey(algorithm: "Ed25519", extractable: boolean, keyUsages: ReadonlyArray<"sign" | "verify">): Promise<CryptoKeyPair>;
+  public generateKey(algorithm: "X25519", extractable: boolean, keyUsages: ReadonlyArray<"deriveBits" | "deriveKey">): Promise<CryptoKeyPair>;
   public generateKey(algorithm: RsaHashedKeyGenParams | EcKeyGenParams, extractable: boolean, keyUsages: KeyUsage[]): Promise<CryptoKeyPair>;
   public generateKey(algorithm: AesKeyGenParams | HmacKeyGenParams | Pbkdf2Params, extractable: boolean, keyUsages: KeyUsage[]): Promise<CryptoKey>;
   public generateKey(algorithm: globalThis.AlgorithmIdentifier, extractable: boolean, keyUsages: KeyUsage[]): Promise<CryptoKeyPair | CryptoKey>;