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

[cpp] view plain copy

1. @implementationWQKeyChain
2. +(NSMutableDictionary*)getKeychainQuery:(NSString*)service{
3. return[NSMutableDictionarydictionaryWithObjectsAndKeys:
4. (__bridge_transferid)kSecClassGenericPassword,(__bridge_transferid)kSecClass,
5. service,(__bridge_transferid)kSecAttrService,
6. service,(__bridge_transferid)kSecAttrAccount,
7. (__bridge_transferid)kSecAttrAccessibleAfterFirstUnlock,(__bridge_transferid)kSecAttrAccessible,
8. nil];
9. }
11. +(void)save:(NSString*)servicedata:(id)data{
12. //Getsearchdictionary
13. NSMutableDictionary*keychainQuery=[selfgetKeychainQuery:service];
14. //Deleteolditembeforeaddnewitem
15. SecItemDelete((__bridge_retainedCFDictionaryRef)keychainQuery);
16. //Addnewobjecttosearchdictionary(Attention:thedataformat)
17. [keychainQuerysetObject:[NSKeyedArchiverarchivedDataWithRootObject:data]forKey:(__bridge_transferid)kSecValueData];
18. //Additemtokeychainwiththesearchdictionary
19. SecItemAdd((__bridge_retainedCFDictionaryRef)keychainQuery,NULL);
20. }
22. +(id)load:(NSString*)service{
23. idret=nil;
24. NSMutableDictionary*keychainQuery=[selfgetKeychainQuery:service];
25. //Configurethesearchsetting
26. [keychainQuerysetObject:(id)kCFBooleanTrueforKey:(__bridge_transferid)kSecReturnData];
27. [keychainQuerysetObject:(__bridge_transferid)kSecMatchLimitOneforKey:(__bridge_transferid)kSecMatchLimit];
28. CFDataRefkeyData=NULL;
29. if(SecItemCopyMatching((__bridge_retainedCFDictionaryRef)keychainQuery,(CFTypeRef*)&keyData)==noErr){
30. @try{
31. ret=[NSKeyedUnarchiverunarchiveObjectWithData:(__bridge_transferNSData*)keyData];
32. }@catch(NSException*e){
33. NSLog(@"Unarchiveof%@failed:%@",service,e);
34. }@finally{
35. }
36. }
37. returnret;
38. }
40. +(void)delete:(NSString*)service{
41. NSMutableDictionary*keychainQuery=[selfgetKeychainQuery:service];
42. SecItemDelete((__bridge_retainedCFDictionaryRef)keychainQuery);
43. }
44. @end

比如，保存密码

[cpp] view plain copy

1. @interfaceWQUserDataManager:NSObject
3. /**
4. *@brief存储密码
5. *
6. *@parampassword密码内容
7. */
8. +(void)savePassWord:(NSString*)password;
10. /**
11. *@brief读取密码
12. *
13. *@return密码内容
14. */
15. +(id)readPassWord;
17. /**
18. *@brief删除密码数据
19. */
20. +(void)deletePassWord;
22. @end

[cpp] view plain copy

1. #import"WQUserDataManager.h"
3. @implementationWQUserDataManager
5. staticNSString*constKEY_IN_KEYCHAIN=@"com.wuqian.app.allinfo";
6. staticNSString*constKEY_PASSWORD=@"com.wuqian.app.password";
8. +(void)savePassWord:(NSString*)password
9. {
10. NSMutableDictionary*usernamepasswordKVPairs=[NSMutableDictionarydictionary];
11. [usernamepasswordKVPairssetObject:passwordforKey:KEY_PASSWORD];
12. [WQKeyChainsave:KEY_IN_KEYCHAINdata:usernamepasswordKVPairs];
13. }
15. +(id)readPassWord
16. {
17. NSMutableDictionary*usernamepasswordKVPair=(NSMutableDictionary*)[WQKeyChainload:KEY_IN_KEYCHAIN];
18. return[usernamepasswordKVPairobjectForKey:KEY_PASSWORD];
19. }
21. +(void)deletePassWord
22. {
23. [WQKeyChaindelete:KEY_IN_KEYCHAIN];
24. }
25. @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

[cpp] view plain copy

1. -(IBAction)btnAciton:(id)sender
2. {
3. [WQUserDataManagersavePassWord:self.textfield.text];
4. self.label.text=[WQUserDataManagerreadPassWord];
5. }

达到了预期的效果。

转：http://blog.youkuaiyun.com/weiqubo/article/details/7691278