iOS 钥匙串安全

在iOS开发中，钥匙串是一种非常重要的安全机制。它提供了一种安全存储敏感数据的方式，比如密码、证书、API密钥等。iOS的钥匙串安全机制可以确保这些敏感数据不会被恶意应用程序或未授权的第三方应用程序访问。本文将介绍iOS钥匙串安全的基本原理和使用方法，并提供一个案例代码来演示如何在应用程序中使用钥匙串存储敏感数据。

swift
import UIKit
import Security
class KeychainExampleViewController: UIViewController {
    let serviceName = "com.example.app"
    let accountName = "userPassword"
    override func viewDidLoad() {
        super.viewDidLoad()
        
        // 存储密码
        let password = "password123"
        savePassword(password: password)
        
        // 读取密码
        let savedPassword = readPassword()
        print("Saved password: \(savedPassword)")
    }
    func savePassword(password: String) {
        guard let passwordData = password.data(using: .utf8) else {
            return
        }
        
        let query = [
            kSecClass: kSecClassGenericPassword,
            kSecAttrService: serviceName,
            kSecAttrAccount: accountName,
            kSecValueData: passwordData
        ] as CFDictionary
        
        let status = SecItemAdd(query, nil)
        if status != errSecSuccess {
            print("Failed to save password")
        }
    }
    func readPassword() -> String? {
        let query = [
            kSecClass: kSecClassGenericPassword,
            kSecAttrService: serviceName,
            kSecAttrAccount: accountName,
            kSecReturnData: kCFBooleanTrue!,
            kSecMatchLimit: kSecMatchLimitOne
        ] as CFDictionary
        
        var result: AnyObject?
        let status = SecItemCopyMatching(query, &result)
        if status == errSecSuccess, let passwordData = result as? Data {
            return String(data: passwordData, encoding: .utf8)
        } else {
            print("Failed to read password")
            return nil
        }
    }
}