iOS设备唯一标识-(UUID+Keychain)

在iOS设备上获取唯一的设备标识符需要特别注意隐私保护。苹果为了保护用户隐私，限制了开发者直接访问设备的唯一标识符（如UDID）。不过，可以采用UUID+Keychain方式代替唯一标识。

将UUID存储于Keychain中，这种方法的好处是，当用户卸载并重新安装应用时，这个标识符会保持不变，但如果用户更换了设备，则会生成新的标识符。

具体实现如下：

1、导入 Security 框架

import Security

2、定义Keychain操作函数

import UIKit
import Security

// 将信息存入Keychain中，用户卸载应用信息不丢失
class DPKeychain {
    // 将字符串值保存到Keychain中。
    static func saveToKeychain(_ value: String, service: String, account: String) -> Bool {
        guard let data = value.data(using: .utf8) else { return false }
        
        // 删除旧的数据
        SecItemDelete(query(service: service, account: account) as CFDictionary)
        
        // 添加新的数据
        let query = [
            kSecClass as String: kSecClassGenericPassword,
            kSecAttrService as String: service,
            kSecAttrAccount as String: account,
            kSecValueData as String: data
        ] as [String: Any]
        
        let status = SecItemAdd(query as CFDictionary, nil)
        return status == errSecSuccess
    }
    // 从Keychain中加载字符串值
    static func loadFromKeychain(service: String, account: String) -> String? {
        let query = [
            kSecClass as String: kSecClassGenericPassword,
            kSecAttrService as String: service,
            kSecAttrAccount as String: account,
            kSecReturnData as String: kCFBooleanTrue!,
            kSecMatchLimit as String: kSecMatchLimitOne
        ] as [String: Any]
        
        var item: AnyObject?
        let status = SecItemCopyMatching(query as CFDictionary, &item)
        
        if status == errSecSuccess, let data = item as? Data {
            return String(data: data, encoding: .utf8)
        }
        
        return nil
    }
    // 从Keychain中删除指定的服务和账户的数据。
    static func deleteFromKeychain(service: String, account: String) -> Bool {
        let query = query(service: service, account: account)
        let status = SecItemDelete(query as CFDictionary)
        return status == errSecSuccess
    }
    
    private static func query(service: String, account: String) -> [String: Any] {
        return [
            kSecClass as String: kSecClassGenericPassword,
            kSecAttrService as String: service,
            kSecAttrAccount as String: account
        ]
    }
    
    
}

3、创建Keychain服务

let keychainService = "com.yourcompany.yourapp" 
let keychainAccount = "uniqueIdentifier"

4、使用UUID

import UIKit

// keychainService = com.yourcompany.yourapp
let keychainService = "com.wh.b"
let keychainAccount = "uniqueIdentifier"

class DPUser {
    
    // 获取iOS设备唯一标识
   static func getUniqueIdentifier() -> String {
        // 检查Keychain中是否已有UUID，如果有则返回，否则生成新的UUID并保存到Keychain中。
        if let identifier = DPKeychain.loadFromKeychain(service: keychainService, account: keychainAccount) {
            return identifier
        } else {
            let newIdentifier = UUID().uuidString
            let success = DPKeychain.saveToKeychain(newIdentifier, service: keychainService, account: keychainAccount)
            if !success {
                print("Failed to save unique identifier to Keychain")
            }
            return newIdentifier
        }
    }
}

// 获取唯一标识符
let uniqueIdentifier = DPUser.getUniqueIdentifier()
print("当前设备唯一标识-UUID: \(uniqueIdentifier)")

此处有demo