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