keychain应用

1.kSecClass key 定义属于那一种类型的keyChain
2.不同的类型包含不同的Attributes,这些attributes定义了这个item的具体信息
3.每个item可以包含一个密码项来存储对应的密码

使用:
引入Security包，引入文件 #import <Security/Security.h>

添加

- (IBAction)add:(id)sender {
    if (nameField.text.length > 0 && passwordField.text.length > 0) {
        // 一个mutable字典结构存储item信息
        NSMutableDictionary* dic = [NSMutableDictionary dictionary];
        // 确定所属的类class
        [dic setObject:(id)kSecClassGenericPassword forKey:(id)kSecClass];
        // 设置其他属性attributes
        [dic setObject:nameField.text forKey:(id)kSecAttrAccount];
        // 添加密码 secValue  注意是object 是 NSData
        [dic setObject:[passwordField.text dataUsingEncoding:NSUTF8StringEncoding] forKey:(id)kSecValueData];
        // SecItemAdd
        OSStatus s = SecItemAdd((CFDictionaryRef)dic, NULL);
        NSLog(@"add : %ld",s);
    }
}

查找

// 查找全部
- (IBAction)sel:(id)sender {
    NSDictionary* query = [NSDictionary dictionaryWithObjectsAndKeys:kSecClassGenericPassword,kSecClass, 
                           kSecMatchLimitAll,kSecMatchLimit,
                           kCFBooleanTrue,kSecReturnAttributes,nil];
    CFTypeRef result = nil;
    OSStatus s = SecItemCopyMatching((CFDictionaryRef)query, &result);
    NSLog(@"se;ect all : %ld",s);
    NSLog(@"%@",result);
}


// 按名称查找
- (IBAction)sname:(id)sender {
    if (nameField.text.length >0) {
        // 查找条件：1.class 2.attributes 3.search option
        NSDictionary* query = [NSDictionary dictionaryWithObjectsAndKeys:kSecClassGenericPassword,kSecClass, 
                               nameField.text,kSecAttrAccount,
                               kCFBooleanTrue,kSecReturnAttributes,nil];
        CFTypeRef result = nil;
        // 先找到一个item
        OSStatus s = SecItemCopyMatching((CFDictionaryRef)query, &result);
        NSLog(@"select name : %ld",s);  //  errSecItemNotFound 就是找不到
        NSLog(@"%@",result);        
        if (s == noErr) {
            // 继续查找item的secValue
            NSMutableDictionary* dic = [NSMutableDictionary dictionaryWithDictionary:result];
            // 存储格式
            [dic setObject:(id)kCFBooleanTrue forKey:kSecReturnData];
            // 确定class
            [dic setObject:[query objectForKey:kSecClass] forKey:kSecClass];
            NSData* data = nil;
            // 查找secValue
            if (SecItemCopyMatching((CFDictionaryRef)dic, (CFTypeRef*)&data) == noErr) {
                if (data.length)
                    NSLog(@"%@",[[[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding] autorelease]);
            }
        }
    }
}

修改

- (IBAction)update:(id)sender {
    if (nameField.text.length >0 && passwordField.text.length > 0) {
        // 先查找看看有没有
        NSDictionary* query = [NSDictionary dictionaryWithObjectsAndKeys:kSecClassGenericPassword,kSecClass, 
                               nameField.text,kSecAttrAccount,
                               kCFBooleanTrue,kSecReturnAttributes,nil];
        
        CFTypeRef result = nil;
        if (SecItemCopyMatching((CFDictionaryRef)query, &result) == noErr)
        {    
            // 更新后的数据，基础是搜到的result
            NSMutableDictionary* update = [NSMutableDictionary dictionaryWithDictionary:(NSDictionary*)result];
            // 修改要跟新的项 注意先加后删的class项
            [update setObject:[query objectForKey:kSecClass] forKey:kSecClass];
            [update setObject:[passwordField.text dataUsingEncoding:NSUTF8StringEncoding] forKey:kSecValueData];
            [update removeObjectForKey:kSecClass];
#if TARGET_IPHONE_SIMULATOR
            // 模拟器的都有个默认的组“test”，删了，不然会出错
            [update removeObjectForKey:(id)kSecAttrAccessGroup];
#endif
            // 得到要修改的item，根据result，但要添加class
            NSMutableDictionary* updateItem = [NSMutableDictionary dictionaryWithDictionary:result];
            [updateItem setObject:[query objectForKey:(id)kSecClass] forKey:(id)kSecClass];
            // SecItemUpdate
            OSStatus status = SecItemUpdate((CFDictionaryRef)updateItem, (CFDictionaryRef)update);
            NSLog(@"update:%ld",status);

删除

- (IBAction)del:(id)sender {
    if (nameField.text.length >0) {
        // 删除的条件
        NSDictionary* query = [NSDictionary dictionaryWithObjectsAndKeys:kSecClassGenericPassword,kSecClass, 
                               nameField.text,kSecAttrAccount,nil];
        // SecItemDelete
        OSStatus status = SecItemDelete((CFDictionaryRef)query);
        NSLog(@"delete:%ld",status);    // //  errSecItemNotFound 就是没有
    }
}