Re: Turning off screen shot ability
Re: Turning off screen shot ability
- Subject: Re: Turning off screen shot ability
- From: John Joyce <email@hidden>
- Date: Thu, 07 Mar 2013 15:51:35 +0900
Sounds like impossible requirements short of running root processes and heavily modifying software, but still being severely insecure at many levels.
Sounds like you're saying you need to run an app, and also have kb and mouse input, potentially universal access as well.
Sounds like you're also saying you will expect this to run on a system where users may have admin accounts (normal for most ).
You're going to need a lot of caveats to your requirements.
You'll need an installer, because you're going to need to do things as root.
KB shortcuts for screen capture are in System Prefs and can be enabled/disabled there and kb shortcuts are customizable.
You can find the tool in /usr/sbin/screencapture and you would need to disable it or relocate it temporarily. This could be as simple as modifying the user shell path or moving the tool temporarily.
(requiring admin authorization either when you app launches or when you run an installer to install privileged tools.)
That will take care of screenshots, but it has nothing to do with Cocoa specifically.
Your app will most certainly not make in into MAS.
You will still need to account for admin users modifying things.
They can enable root easily.
HW access means running in single user mode easily.
You will need to detect and handle external displays. Those are easily recorded.
If it is a Mac without a built-in display, it is all to easy to capture a video signal from the port.
Never mind mounting the disk from another system that may ignore file permissions easily.
Still doesn't account for unknown software and processes on a system that may be running already with escalated privileges before yours launches.
Apple Remote Deskop or other remote management & screensharing tools?
You probably don't want to go into trying to white list processes.
Still does not account for cameras taking pictures which can then be OCR'd easily too.
Your app will likely be easily cracked or otherwise circumvented as long as users can have hardware access & admin access.
That leaves a severe amount of complex obfuscation and custom view drawing.
You need a root kit, but your worst enemy will be another root kit.
On Mar 7, 2013, at 2:33 PM, Brad O'Hearne <email@hidden> wrote:
> Lee Ann,
>
> Thanks for the reply. I took a look at the "Son of Grab" app -- if I've understood it correctly, it appears to be related to the setSharingType property of the window in question, which I already have set to none -- which means no other process should be able to capture it. It appears that isn't the case with Command-Shift-3 however, which seems to still create screen shots unimpeded.
>
> Brad
>
> On Mar 6, 2013, at 2:14 PM, Lee Ann Rucker <email@hidden> wrote:
>
>>
>> On Mar 6, 2013, at 9:02 AM, Jens Alfke wrote:
>>
>>>
>>> On Mar 6, 2013, at 8:37 AM, Brad O'Hearne <email@hidden> wrote:
>>>
>>>> I am interested in the capabilities of the machine (OS X) and if so, how. I need to programmatically within an app (not by external system administration) turn off all screen capture capability, by hotkeys, or by grabbing the contents of the window.
>>>
>>> Apple’s DVD player app does this, for DRM purposes*. I don’t know how it manages it, whether it’s some public system API or an internal-only thing … but it might be a useful clue to track down.
>>
>> I'd start with the "Son Of Grab" sample app; it shows how to get the contents of other app's windows, so that's where I'd look to figure out how to prevent that.
>
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