iOS开发——keychain的使用

通常情况下，我们用NSUserDefaults存储数据信息，但是对于一些私密信息，比如密码、证书等等，就需要使用更为安全的keychain了。keychain里保存的信息不会因App被删除而丢失，在用户重新安装App后依然有效，数据还在。

使用苹果官方发布的KeychainItemWrapper或者SFHFKeychainUtils很方便，后来看到 iphone使用keychain来存取用户名和密码 一文，觉得对了解keychain有很大的帮助，于是ARC控也尝试了一把。

需要导入Security.framework 

@implementation WQKeyChain

+ (NSMutableDictionary *)getKeychainQuery:(NSString *)service {

    

    return [NSMutableDictionarydictionaryWithObjectsAndKeys:

            

            (__bridge_transferid)kSecClassGenericPassword,(__bridge_transferid)kSecClass,

            

            service, (__bridge_transferid)kSecAttrService,

            

            service, (__bridge_transferid)kSecAttrAccount,

            

            (__bridge_transferid)kSecAttrAccessibleAfterFirstUnlock,(__bridge_transferid)kSecAttrAccessible,

            

           nil];

    

}

+ (void)save:(NSString *)service data:(id)data {

    

    //Get search dictionary

    

   NSMutableDictionary *keychainQuery = [selfgetKeychainQuery:service];

    

    //Delete old item before add new item

    

   SecItemDelete((__bridge_retainedCFDictionaryRef)keychainQuery);

    

    //Add new object to search dictionary(Attention:the data format)

    

    [keychainQuery setObject:[NSKeyedArchiverarchivedDataWithRootObject:data] forKey:(__bridge_transferid)kSecValueData];

    

    //Add item to keychain with the search dictionary

    

   SecItemAdd((__bridge_retainedCFDictionaryRef)keychainQuery, NULL);

    

}

+ (id)load:(NSString *)service {

    

   id ret = nil;

    

   NSMutableDictionary *keychainQuery = [selfgetKeychainQuery:service];

    

    //Configure the search setting

    

    [keychainQuerysetObject:(id)kCFBooleanTrueforKey:(__bridge_transferid)kSecReturnData];

    

    [keychainQuery setObject:(__bridge_transferid)kSecMatchLimitOneforKey:(__bridge_transferid)kSecMatchLimit];

    

   CFDataRef keyData = NULL;

    

   if (SecItemCopyMatching((__bridge_retainedCFDictionaryRef)keychainQuery, (CFTypeRef *)&keyData) ==noErr) {

        

       @try {

            

            ret = [NSKeyedUnarchiverunarchiveObjectWithData:(__bridge_transferNSData *)keyData];

            

        }@catch (NSException *e) {

            

            NSLog(@"Unarchive of %@ failed: %@", service, e);

            

        }@finally {

            

        }

        

    }

    

   return ret;

    

}

+ (void)delete:(NSString *)service {

    

   NSMutableDictionary *keychainQuery = [selfgetKeychainQuery:service];

    

   SecItemDelete((__bridge_retainedCFDictionaryRef)keychainQuery);

    

}

@end

@interface WQUserDataManager :NSObject

/**

 

 *    @brief    存储密码

 

 *

 

 *    @param     password     密码内容

 

 */

+(void)savePassWord:(NSString *)password;

/**

 

 *    @brief    读取密码

 

 *

 

 *    @return    密码内容

 

 */

+(id)readPassWord;

/**

 

 *    @brief    删除密码数据

 

 */

+(void)deletePassWord;

@end

#import "WQUserDataManager.h"

@implementation WQUserDataManager

static NSString *const KEY_IN_KEYCHAIN =@"com.wuqian.app.allinfo";

static NSString *const KEY_PASSWORD =@"com.wuqian.app.password";

+(void)savePassWord:(NSString *)password

{

    

    NSMutableDictionary *usernamepasswordKVPairs = [NSMutableDictionarydictionary];

    

    [usernamepasswordKVPairssetObject:password forKey:KEY_PASSWORD];

    

    [WQKeyChain save:KEY_IN_KEYCHAIN data:usernamepasswordKVPairs];

    

}

+(id)readPassWord

{

    

   NSMutableDictionary *usernamepasswordKVPair = (NSMutableDictionary *)[WQKeyChain load:KEY_IN_KEYCHAIN];

    

   return [usernamepasswordKVPair objectForKey:KEY_PASSWORD];

    

}

+(void)deletePassWord

{

    

    [WQKeyChain delete:KEY_IN_KEYCHAIN];

    

}

@end

实现一个简单的界面，把设定的密码存起来，然后立即读取显示出来看看效果

-(IBAction)btnAciton:(id)sender
{
    [WQUserDataManager savePassWord:self.textfield.text];
    self.label.text = [WQUserDataManager readPassWord];
}