1.为什么使用Keychain
- iOS设备中的Keychain是一个安全的存储容器.
- 它可以用来为不同应用保存敏感信息比如用户名,密码,网络密码,认证令牌等等。
- 它是一个sqlite数据库,文件路径为:/private/var/Keychains/keychain-2.db,其保存的所有数据都是加密过的。
- 通过keychain access groups可以在应用之间共享keychain中的数据。要使用共享数据就需要在我们保存数据到keychain的时候指定group
- 而把数据保存到keychain的最好方法就是用苹果提供的KeychainItemWrapper,后面会提到。
就我目前所用的App中使用Keychain的典型App就是百度云,大家可以自行下载看看效果。
创建Keychain单例
#import <Foundation/Foundation.h>
#import <Security/Security.h>
@interface LRKeychain : NSObject
+ (void)addKeychainData:(id)data forKey:(NSString *)key;///< 添加数据
+ (id)getKeychainDataForKey:(NSString *)key;///< 根据key获取相应的数据
+ (void)deleteKeychainDataForKey:(NSString *)key;///< 删除数据
@end
#import "LRKeychain.h"
#define Key_User_PhoneNumber @"cn.reader.phoneNumber"
#define Key_User_Password @"cn.reader.password"
@implementation LRKeychain
+ (NSMutableDictionary *)getKeychainQuery:(NSString *)service {
return [NSMutableDictionary dictionaryWithObjectsAndKeys:
(__bridge id)kSecClassGenericPassword,(id)kSecClass,// 标识符(kSecAttrGeneric通常值位密码)
service, (__bridge id)kSecAttrService,// 服务(kSecAttrService)
service, (__bridge id)kSecAttrAccount,// 账户(kSecAttrAccount)
(__bridge id)kSecAttrAccessibleAfterFirstUnlock,(__bridge id)kSecAttrAccessible,// kSecAttrAccessiblein变量用来指定这个应用何时需要访问这个数据
nil];
}
+ (void)addKeychainData:(id)data forKey:(NSString *)key {
// 获取查询字典
NSMutableDictionary *keychainQuery = [self getKeychainQuery:key];
// 在删除之前先删除旧数据
SecItemDelete((__bridge CFDictionaryRef)keychainQuery);
// 添加新的数据到字典
[keychainQuery setObject:[NSKeyedArchiver archivedDataWithRootObject:data] forKey:(__bridge id)kSecValueData];
// 将数据字典添加到钥匙串
SecItemAdd((__bridge CFDictionaryRef)keychainQuery, NULL);
}
+ (id)getKeychainDataForKey:(NSString *)key {
id ret = nil;
NSMutableDictionary *keychainQuery = [self getKeychainQuery: key];
[keychainQuery setObject:(id)kCFBooleanTrue forKey:(__bridge_transfer id)kSecReturnData];
[keychainQuery setObject:(__bridge_transfer id)kSecMatchLimitOne forKey:(__bridge_transfer id)kSecMatchLimit];
CFDataRef keyData = NULL;
if (SecItemCopyMatching((__bridge_retained CFDictionaryRef)keychainQuery, (CFTypeRef *)&keyData) == noErr) {
@try {
ret = [NSKeyedUnarchiver unarchiveObjectWithData:(__bridge_transfer NSData *)keyData];
} @catch (NSException *e) {
NSLog(@"Unarchive of %@ failed: %@", key, e);
} @finally {
}
}
return ret;
}
+ (void)deleteKeychainDataForKey:(NSString *)key {
NSMutableDictionary *keychainQuery = [self getKeychainQuery: key];
SecItemDelete((__bridge_retained CFDictionaryRef)keychainQuery);
}
@end
使用单例
#import "ViewController.h"
#import "LRKeychain.h"
static NSString *key = @"Mr.Yan";
@interface ViewController ()
@property (weak, nonatomic) IBOutlet UITextField *topTextField;
@property (weak, nonatomic) IBOutlet UITextField *bottomTextField;
@end
@implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
- (IBAction)addMessage:(UIButton *)sender {
if ([LRKeychain getKeychainDataForKey:key]) {
NSLog(@"该key内已有数据,为:%@",[LRKeychain getKeychainDataForKey:key]);
[LRKeychain addKeychainData:self.topTextField.text forKey:key];
NSLog(@"该key内容被修改为:%@",[LRKeychain getKeychainDataForKey:key]);
}else{
NSLog(@"该key不存在,写入内容");
[LRKeychain addKeychainData:self.topTextField.text forKey:key];
NSLog(@"已写入,该key内容:%@",[LRKeychain getKeychainDataForKey:key]);
}
}
- (IBAction)GetMessage:(UIButton *)sender {
self.bottomTextField.text = [LRKeychain getKeychainDataForKey:key];
}
- (IBAction)DeleteMessage:(UIButton *)sender {
[LRKeychain deleteKeychainDataForKey:key];
}
@end