IOS KeyChain理解及代碼案例

IOS KeyChain理解及代碼案例

對KeyChain的理解，可參照http://my.oschina.net/w11h22j33/blog/206713

文中利用KeyChain儲存使用者名稱和密碼，使用者名稱放在屬性中，密碼放在密碼項中；其中對KeyChain項的增刪改查，我個人覺得是有問題的，為了方面自己代碼上的使用，也協助閱讀該文的其他讀者更好的理解，我修正了代碼如下：

 

 

//儲存/增加-(IBAction)saveClicked:(id)sender{        if(_nameTF.text.length > 0 && _psdTF.text.length > 0) {        NSMutableDictionary* dic = [NSMutableDictionary dictionary];                [dic setObject:(__bridge_transfer id)kSecClassGenericPassword forKey:(__bridge_transfer id)kSecClass];        [dic setObject:_nameTF.text forKey:(__bridge_transfer id)kSecAttrAccount];        [dic setObject:[_psdTF.text dataUsingEncoding:NSUTF8StringEncoding] forKey:(__bridge_transfer id)kSecValueData];                OSStatus s = SecItemAdd((__bridge_retained CFDictionaryRef)dic, NULL);        NSLog(@%d,s);    }}//擷取/查詢-(IBAction)showClicked:(id)sender{    if(_nameTF.text.length > 0) {        NSDictionary* query = [NSDictionary dictionaryWithObjectsAndKeys:                               (__bridge_transfer id)kSecClassGenericPassword, (__bridge_transfer id)kSecClass,                               _nameTF.text, (__bridge_transfer id)kSecAttrAccount,                               kCFBooleanTrue, kSecReturnAttributes,nil];                CFTypeRef result = nil;        OSStatus s = SecItemCopyMatching((__bridge_retained CFDictionaryRef)query, &result);                NSLog(@%d,s);        NSLog(@%@,result);                if(s == noErr) {//通過使用者名稱判斷item項是否存在            NSMutableDictionary* dic = [NSMutableDictionary dictionary];            [dic setObject:_nameTF.text forKey: (__bridge_transfer id)kSecAttrAccount];            [dic setObject:(__bridge_transfer id)kCFBooleanTrue forKey:(__bridge_transfer id)kSecReturnData];            [dic setObject:(__bridge_transfer id)kSecClassGenericPassword forKey:(__bridge_transfer id)kSecClass];                        CFDataRef dataRef = NULL;            if(SecItemCopyMatching((__bridge_retained CFDictionaryRef)dic, (CFTypeRef*)&dataRef) == noErr) {                                NSData *data = (__bridge_transfer id)dataRef;                NSLog(@%ld, data.length);                                NSLog(@%@,[[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding]);            }        }    }else{                NSDictionary* query = [NSDictionary dictionaryWithObjectsAndKeys:                               (__bridge_transfer id)kSecClassGenericPassword,(__bridge_transfer id)kSecClass,                               (__bridge_transfer id)kSecMatchLimitAll, (__bridge_transfer id)kSecMatchLimit,                               (__bridge_transfer id)kCFBooleanTrue,(__bridge_transfer id)kSecReturnAttributes,nil];                CFArrayRef result = NULL;        OSStatus s = SecItemCopyMatching((__bridge_retained CFDictionaryRef)query, (CFTypeRef*)&result);                NSArray *array = (__bridge_transfer NSArray*)result;//(可以遍曆所有keychain項)                NSLog(@%d,s);        NSLog(@%@,result);    }        }//刪除-(IBAction)delClicked:(id)sender{        if(_nameTF.text.length > 0){        NSDictionary* query = [NSDictionary dictionaryWithObjectsAndKeys:(__bridge_transfer id)kSecClassGenericPassword,kSecClass,                               _nameTF.text,kSecAttrAccount,nil];        OSStatus status = SecItemDelete((__bridge_retained CFDictionaryRef)query);        NSLog(@%d,status);    }}//改-(IBAction)modifyClicked:(id)sender{        if(_nameTF.text.length > 0 && _psdTF.text.length > 0) {        NSDictionary* query = [NSDictionary dictionaryWithObjectsAndKeys:                               (__bridge_transfer id)kSecClassGenericPassword, (__bridge_transfer id)kSecClass,                               _nameTF.text, (__bridge_transfer id)kSecAttrAccount,                               (__bridge_transfer id)kCFBooleanTrue, (__bridge_transfer id)kSecReturnAttributes,nil];                CFTypeRef result = nil;        if(SecItemCopyMatching((__bridge_retained CFDictionaryRef)query, &result) == noErr)//存在才修改        {            //設定需要更新的屬性列表，一定要刪除kSecClass，因為不能update不該欄位，否則會報錯            NSMutableDictionary* update = [[NSMutableDictionary alloc]init];            [update setObject:[_psdTF.text dataUsingEncoding:NSUTF8StringEncoding] forKey:(__bridge_transfer id)kSecValueData];            [update removeObjectForKey:(__bridge_transfer id)kSecClass];                        //設定尋找條件，即根據這個條件找到keychain項            NSMutableDictionary* updateItem = [[NSMutableDictionary alloc]init];            [updateItem setObject:[query objectForKey:(__bridge_transfer id)kSecClass] forKey:(__bridge_transfer id)kSecClass];            [updateItem setObject:_nameTF.text forKey:(__bridge_transfer id)kSecAttrAccount];                        //參數一表示要查虛的，參數二表示更新後的值            OSStatus status = SecItemUpdate((__bridge_retained CFDictionaryRef)updateItem, (__bridge_retained CFDictionaryRef)update);            NSLog(@%d,status);        }    }}