UUID, keyID: String) throws -> String { let object = UnsafeMutablePointer<OpaquePointer?>.allocate(capacity: MemoryLayout<OpaquePointer>.size) jwt_new(object) defer { jwt_free(object.pointee) } let keyPointer = convertToCString(privateKey) defer { keyPointer.deallocate() } jwt_set_alg(object.pointee, JWT_ALG_ES256, keyPointer, Int32(privateKey.utf16.count + 1)) // https://github.com/benmcollins/libjwt/pull/71 jwt_add_header(object.pointee, "kid", keyID) jwt_add_grant(object.pointee, "iss", issuerID.uuidString.lowercased()) let expirationDate = Date().addingTimeInterval(expirationInterval) jwt_add_grant_int(object.pointee, "exp", Int(expirationDate.timeIntervalSince1970)) jwt_add_grant(object.pointee, "aud", "appstoreconnect-v1") guard let encodedCString = jwt_encode_str(object.pointee) else { throw Error.decodeError } return String(cString: encodedCString) } }