iOS开发-基础:keychain的使用

转自: http://www.cnblogs.com/ios8/archive/2012/06/25/iOS-keychain.html

简介 :

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 

KeyChain类

@implementation WQKeyChain

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

return [NSMutableDictionary dictionaryWithObjectsAndKeys:

        (__bridge_transfer id)kSecClassGenericPassword,(__bridge_transfer id)kSecClass,

        service, (__bridge_transfer id)kSecAttrService,

        service, (__bridge_transfer id)kSecAttrAccount,

        (__bridge_transfer id)kSecAttrAccessibleAfterFirstUnlock,(__bridge_transfer id)kSecAttrAccessible,

        nil];

}



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

    //Get search dictionary

    NSMutableDictionary *keychainQuery = [self getKeychainQuery:service];

    //Delete old item before add new item

    SecItemDelete((__bridge_retained CFDictionaryRef)keychainQuery);

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

    [keychainQuery setObject:[NSKeyedArchiver archivedDataWithRootObject:data] forKey:(__bridge_transfer id)kSecValueData];

    //Add item to keychain with the search dictionary

    SecItemAdd((__bridge_retained CFDictionaryRef)keychainQuery, NULL);

}



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

    id ret = nil;

    NSMutableDictionary *keychainQuery = [self getKeychainQuery:service];

    //Configure the search setting

    [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: %@", service, e);

        } @finally {

        }

    }

    return ret;

}



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

    NSMutableDictionary *keychainQuery = [self getKeychainQuery:service];

    SecItemDelete((__bridge_retained CFDictionaryRef)keychainQuery);

}

@end

例子: 保存密码

.h

@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

.m

#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 = [NSMutableDictionary dictionary];

    [usernamepasswordKVPairs setObject: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