如何在coredata中存储大小为4096的kSecAttrKeyTypeRSA类型的公钥和私钥，而不是密钥链

import CoreData
import Security

// 创建CoreData模型
let modelURL = Bundle.main.url(forResource: "YourDataModel", withExtension: "momd")!
let managedObjectModel = NSManagedObjectModel(contentsOf: modelURL)!
let persistentStoreCoordinator = NSPersistentStoreCoordinator(managedObjectModel: managedObjectModel)
let managedObjectContext = NSManagedObjectContext(concurrencyType: .mainQueueConcurrencyType)
managedObjectContext.persistentStoreCoordinator = persistentStoreCoordinator

// 生成RSA密钥对
let privateKeyAttr: [String: Any] = [
    kSecAttrIsPermanent as String: true,
    kSecAttrApplicationTag as String: "com.example.privatekey",
    kSecAttrKeyType as String: kSecAttrKeyTypeRSA,
    kSecAttrKeySizeInBits as String: 4096
]
let publicKeyAttr: [String: Any] = [
    kSecAttrIsPermanent as String: true,
    kSecAttrApplicationTag as String: "com.example.publickey",
    kSecAttrKeyType as String: kSecAttrKeyTypeRSA,
    kSecAttrKeySizeInBits as String: 4096
]
var publicKey, privateKey: SecKey?
SecKeyGeneratePair(privateKeyAttr as CFDictionary, publicKeyAttr as CFDictionary, &publicKey, &privateKey)

// 转换密钥为NSData
var error: Unmanaged<CFError>?
let publicKeyData = SecKeyCopyExternalRepresentation(publicKey!, &error) as Data
let privateKeyData = SecKeyCopyExternalRepresentation(privateKey!, &error) as Data

// 创建CoreData实体对象并保存
let entity = NSEntityDescription.entity(forEntityName: "KeyPair", in: managedObjectContext)!
let keyPair = NSManagedObject(entity: entity, insertInto: managedObjectContext)
keyPair.setValue(publicKeyData, forKey: "publicKey")
keyPair.setValue(privateKeyData, forKey: "privateKey")

do {
    try managedObjectContext.save()
    print("Key pair saved successfully.")
} catch {
    print("Failed to save key pair: \(error)")
}