Do you know if there are unchangeable EXIF datas ?
In my case i want to know the real date of creation of a jpeg image. So I thought the EXIF's datas was the best way but I realized that with a software like XnView you can change it. So there is any way i can now the real date of the creation of an image ?
In another hand, is it possible to know if a EXIF datas has been modified ?
Thx fo all,
And sorry for my bad english
Have a good day !
:)
In principle, it is not possible to be sure the data hasn't been edited, although it may take a great deal of skill to do so indetectably. Some of the major camera makers (Canon and Nikon, possibly others) offer an "image authentication" feature in their pro model cameras which is designed to make it impossible to modify the image after it has been taken. They do this for the benefit of people doing legal work - evidence shots and the like. To use this, you have to switch it on (via the camera settings) before you take the picture. Even with these though, it is still possible to alter the data: both the Canon and Nikon authentication systems have been cracked (presumably with considerable difficulty).
As for normal pictures, yes, these are very easy to alter. However many (most?) programs which can edit EXIF data leave their own signs. For example, Adobe Photoshop always adds its own name somewhere in the EXIF, apparently whether you want it to or not. You can see this with many different EXIF viewers, especially with the more advanced ones like PhotoME. (Which, sadly, is no longer maintained.)
Short answer: yes, it is always possible to exit EXIF, and almost always possible to do it indetectably, but it may requite the right tools and quite a lot of skill. You can't ever be certain it has not been done.
Related
I'm struggling to choose between a vast number of audio programming languages and APIs. I'm very (totally) new to audio programming so please bear with me.
Software
I need to be able to:
Alter volume of different sounds before outputting them to anything (these sounds can have a variety of different origins, for example mp3s and microphone input)
phase shift sounds
superimpose sounds that I have tweaked (as per items 1 and 2)
control the output to each of 8 channels independently of one another
make this all happen on Windows7
These capabilities need be abstracted by a graphical frontend I will probably make myself. What I want to be able to do is create 'sound sources' and move them around a 3D environment along either pre-defined trajectories and/or in relation to the movement of whoever is inside the rig. The reason I want to do pitch bending is so I can mess with red-shift stuff.
I don't want to have to construct full tracks before-hand and just play them. I want the sound that is played to depend on external input from sensors as well as what I am doing on the frontend.
As far as I know this means I cant use any existing full audio making app.
The Question
I've been looking around for for the API or language I should use and I have not turned up a blank, quite the opposite actually. I'm struggling to narrow down my search. A lot of my problem stems from the fact that I have no experience in audio programming.
So, does anyone know off-hand of an API or language that meets my criteria?
Hardware stuff and goals
(I left this until last because I'm not sure how relevant it is)
My goal is to make three rings of speakers at different heights and to have enough control over them to be able to simulate any number of 'sound sources' within the array. The idea is to have someone stand in the middle of the rig and be able to make it sound like there are lots of things moving around them. To get this working I'm planning on doing a little trig and using 8 channels of audio from my PC. The maths is pretty straight forward, it just the rest that I need to worry about
What I want to do next is attach a bunch of cameras to the thing and do some simple image recognition stuff to be able to 'attach sound sources' to different objects. Eg. If someone is standing in the right place it can be made to seem as though all red balls quack like a duck, and all orange ones moan hauntingly.
This is not to detract from Richard Small's answer, but to comment on some of the other options out there:
If you are looking for something higher-level with which you can prototype and develop this faster, you want max/msp or it's open source competitor puredata. These are designed for musicians who are technically minded, but not so much for programmers. As a result, you can build this sort of thing quickly and efficiently.
You also have some lower level options: PortAudio can handle your audio I/O, you would have to do the sound generation and effects and so on on your own or with other libraries. Cinder and OpenFramewoks both provide interfaces for audio, cameras, and other stuff for "creative programming". I'm afraid I don't know if they meet your full requirements, but they are powerful and popular for this sort of thing so I encorage you to look at them.
The two major ones these days tend to be
WWise
WWise Download Link
FMOD
FMOD Download Link
These two engines may even in fact be overkill for what you need, but I can almost guarantee that they will be capable of anything you require.
I'm putting together a mobile version of a webpage which consists entirely of client art. For the old-fashioned desktop version, I just used PNGs, but I really wanted to use SVG for mobile. SVGZ would be smaller and resolution independent, so it seemed like a perfect use case.
But the client is worried that, once his art is online in SVG, anyone could download the files and use his art illegally (he's had stuff he worked on pirated before, so he takes this pretty seriously.) This had never occurred to me until he brought it up, but the SVG would basically be his original source art.
I was wondering if there's any way to prevent the SVG files from being accessed by the user. As far I know this is impossible -- making the files available to the user-agent means making them available to the user -- but I wanted to ask around to be sure.
Thanks for any help.
No, this is impossible. If a web browser can request the files for display, then any computer anywhere can request the files and save the direct results.
Serving up intentionally degraded artwork (e.g. rasterization) is the only way to prevent people from having the originals. Of course, a determined thief could still re-trace the PNG and get a vectorized, resolution-independent close approximation of the original.
Your client could alternatively:
Include copyright comments in the source, proving ownership. (Yes, a thief could delete these.)
Include 'hidden' elements (0% opacity or placed under another item), proving ownership. (Yes, a thief could delete these.)
Use data steganography in the source SVG to watermark it (e.g. vary the decimal values in a path in a manner minor enough to not effect the result, but still embed custom data). (Yes, any thief suspecting this could lower decimal precision or transform all values in a manner that might remove this.)
Trust in the law to protect his works, or provide a recourse if they are stolen.
Trust in the goodness of most of mankind to not do this.
Decide that theft is the sincerest form of flattery, and not worry about it. :)
I want to code a trading bot for Magic: The Gathering Online. This bot should wait until someone offers to trade, accept, look through the cards available from the other trader (the information is shown on screen), and perform other similar functions. I have several questions:
How can it know that someone is offering a trade?
How can it know that the other trader has some card (the informaion is stored in pictures)?
I just cannot imagine right now how to do it, I have no experience with it, until now I've been coding only console programs for my physics neсessities.
First, you should note that some online games forbid bots, as they can give certain players unfair advantages. The MTGO Terms of Service do not seem to say anything about this, though they do put restrictions on anything that might negatively impact the service. They have also said that there is a possibility they will add an API in the future, so they don't seem to be against the idea of automation, but are not supporting it at the moment. Tread carefully here, but it looks like it should be OK to write a bot as long as it is not harmful or abusive. This is not legal advice, and it would be a good idea to ask the folks who run MTGO for permission. edit since I wrote this, it has been pointed out that there are lots of bots already, so there should be no problems writing bots.
Assuming that it is not forbidden by the terms of service, but they do not have an API, you will have to find a way to detect what's going on, and control the game automatically. There's a pretty good series of articles on writing poker bots (archived copy), which has some good information on how to inject a DLL into an application, scrape the screen, and control the application. That might provide you with a starting point for doing this sort of thing.
You might also want to look for tools that other people have already written for doing this. It looks like there are several existing MTGO bots, but they all seem a bit sketchy (there have been some reports of them stealing passwords), so be careful there.
Edit
Since this answer still seems to be getting upvotes, I should probably update it with some more useful information. Since writing this, I have found a great UI automation system called Sikuli. It allows you to write programs in Python that automate a GUI. It includes image recognition features which make it very easy to recognize buttons, cards, and other UI elements; you just take a screenshot, crop it down to include just the thing you're interested in, and do fuzzy image matching (so that changing backgrounds and the like doesn't cause the match to fail). It even includes a custom IDE that allows you to embed those screenshots directly in your source code, so you can see exactly what the code is looking for. Here's an example from the documentation (apologies for the code formatting, doing images inline in code is not easy given StackOverflow's restricted subset of HTML):
def resizeApp(app, dx, dy):
switchApp(app)
corner = find(Pattern().targetOffset(3,14))
drop_point = corner.getTarget().offset(dx, dy)
dragDrop(corner, drop_point)
resizeApp("Safari", 50, 50)
This is much easier to get started with than the techniques mentioned in the article linked above, of injecting a DLL into the process you are debugging. Sikuli runs entirely at the UI level, so you never have to modify the program you are automating or worry about changes to the internals breaking your script.
One thing it is a bit poor at is handling text; it has OCR features, but they aren't all that good. If the text is selectable, however, you can select the text, copy it, and then look directly at the clipboard.
If I were to write a bot to automate something without a good API or text-based interface, Sikuli is probably the first tool I would reach for.
This answer is constructed from my comments.
What you are trying to do is hard, any way you try and do it.
Arguably the easiest way to do it is to totally mimic the user. So the application presses buttons, moves the mouse etc. The downside with this is that it is dependant on being able to recognise the screen.
This is easier if you can alter the games files as you can then just skin ( changing the image (texture)) the required cards to a single unique colour.
The major down side is you have to have the game as the top level window or have the game running in a virtual machine. Neither of which is ideal.
Another method is to read the processes memory. You may be able to find a list of memory locations, which would make things simpler, otherwise it involves a lot of hardwork, a debugger to deduce the memory addresses. It also helps (a lot) to be able to understand assembly.
The third method is to intercept the packets, and alter them. This is easier that the method above as it (at least for me) is easier to reverse engine the protocol as you have less information to deal with. It is just a matter of setting up a packet sniffer and preforming a action with one variable different (for example, the card) and comparing the differences.
The thing you need to check are that you are not breaking the EULA. I don't know how the game works, but most of the games I have come across have a EULA that prohibits (i.e. You get banned) doing any of the things I have mentioned.
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I want to protect only certain numbers that are displayed after each request. There are about 30 such numbers. I was planning to have images generated in the place of those numerbers, but if the image is not warped as with captcha, wont scripts be able to decipher the number anyway? Also, how much of a performance hit would loading images be vs text?
The only way to make sure bad-guys don't get your data is not to share it with anyone. Any other solution is essentially entering an arms race with the screen-scrapers. At one point or another, one of you will find the arms-race too costly to continue. If the data you are sharing has any perceptible value, then probably the screen-scrapers will be very determined.
It's not possible.
You use javascript and encrypt the page, using document.write() calls after decrypting. I either scrape from the browser's display or feed the page through a JS engine to get the output.
You use Flash. I can poke into the flash file and get the values. You encrypt them in the flash and I can just run it then grab the output from the interpreter's display as a sequence of images.
You use images and I can just feed them through an OCR.
You're in an arms race. What you need to do is make your information so useful and your pages so easy to use that you become the authority source. It's also handy to change your output formats regularly to keep up, but screen scrapers can handle that unless you make fairly radical changes. Radical changes drive users away because the page is continually unfamiliar to them.
Your image solution wont' help much, and images are far less efficient. A number is usually only a few bytes long in HTML encoding. Images start at a few hundred bytes and expand to a 1k or more depending on how large you want. Images also will not render in the font the user has selected for their browser window, and are useless to people who use assisted computing devices (visually impaired people).
Apart from the images, you could display the numbers using JavaScript or flash.
You could also use CSS to position individual digits using various combinations of absolute or relative positions.
You could also use JavaScript to help you create these DIV.
The point is just to obfuscate enough that it becomes really hard.
One more solution is to use images of segments or single dots and re-construct the images of the digits using CSS, a bit like a dot-matrix display.
You could litter the source of the page with these absolutely positioned DIVs and again make it more difficult to reconstruct by creating them dynamically.
At any rate, you can't stop a determined scraper from getting to the data: it doesn't take a lot to automate a web browser and take screenshots that can be fed to an OCR.
There is nothing anyone from paying someone pennies to get the data manually anyway.
The point is: how determined are your opponents (user?).
It's a bit like the software protection business: making things hard enough that you would deter casual 'pirates' is not too hard, and it's a fairly good approach in general.
However, if there is much value in the data you present, there is nothing you can really do to protect it.
All you can do it make it hard enough so that casual 'thieves' will prefer to continue paying for your services rather than circumvent it.
Javascript would probably be the easiest to implement, but you could get really creative and have large blocks of numbers with certain ones being viewable by placing layers on top of the invalid numbers, blending the wrong numbers into the background, or making them invisible via css and semi-randomly generated class names.
I can't believe I'm promoting a common malware scripting tactic, but...
You could encode the numbers as encoded Javascript that gets rendered at runtime.
Generate an image containing those numbers and display the image. :-)
I think you guys are being too reactive with these solutions. Javascript, Capcha, even litigation and the DMCA process don't address the complex adaptive nature of web scraping and data theft. Don't you think the "ideal" solution to prevent malicious bots and website scraping would be something working in a real-time proactive mitigation strategy? Very similar to a Content Protection Network. Just say'n.
Examples:
IBM - IBM ISS Data Security Services
DISTIL - www.distil.it
Can you provide a little more detail on what it is you're doing? Certainly there's a performance hit to create an image instead of dumping out the text of a number, but how often would you be doing this per day?
Using JavaScript is the same as using text. It's trivial to reverse engineer.
Use animated numbers using flash. It may not be fool proof but it would make it harder to crack.
What about posting a lot of dummy numbers and showing the right ones with external CSS? Just as long the scraper doesn't start to parse the external CSS.
Don't output the numbers, i.e. prefix
echo $secretNumber;
with //.
For all those that recommend using Javascript, or CSS to obfuscate the numbers, well there's probably a way around it. Firefox has a plugin called abduction. Basically what it does is saves the page to a file as an image. You could probably modify this plugin to save the image, and then analyze the image to find out the secret number that is trying to be hidden.
Basically, if there's enough incentive behind scraping these numbers from the page, then it will be done. Otherwise, just post a regular number, and make it easier on your users so they won't have to worry so much about not being able to copy and paste the number, or other such problems the result from this trickery.
just do something unexpected and weird (different every time) w/ CSS box model. Force them to actually use a browser backed screenscraper.
I don't think this is possible, you can make their job harder (use images as some suggested here) but this is all you can do, you can't stop a determined person from getting the data, if you don't want them to scrape your data, don't publish it, as simple as that ...
Assuming these numbers are updated often (if they aren't then protecting them is completely moot as a human can just transcribe them by hand) you can limit automated scraping via throttling. An automated script would have to hit your site often to check for updates, if you can limit these checks you win, without resorting to obfuscation.
For pointers on throttling see this question.
My custom homebrew photography processing software, running on 64 bit Linux/GNU, writes out PNG and TIFF files. These are to be sent to a quality printing shop to be made into fine art. Working with interior designers - it's important to get the colors just right!
The print shops usually have no trouble with TIFF and PNGs made from commercial software such as Photoshop. Even though i have the TIFF 6.0 specs, PNG specs, and other info in hand, it is not clear how to include color calibration data or implement color management system on linux. My files are often rejected as faulty, without sufficient error reports to make fixes.
This has been a nasty problem for a while for many. Even my contacts at the Hollywood postproduction studios are struggling with this issue. One studio even wanted to hire me to take care of their color calibration, thinking i was the expert - but no, i am just as blind and lost as everyone!
Does anyone know of good code examples, detailed technical information, or have any other enlightenment? Or time to switch to pure Apple?
Take a look at LittleCMS
http://www.littlecms.com/
This page has the code for applying it to TIFF
http://www.littlecms.com/newutils.htm
The basic thing you need to know is that Color profile data is something you need to store in the meta-data of the file itself.
There is a consultant called Charles Poynton who specialises in this area. I work for one of the post production studios you mention (albeit in london not hollywood), and have seen him speak on the subject a couple of times. His website contains a lot of the material he presents and you might find something of use there. He also has a book called Digital Video and HDTV Algorithms and Interfaces which is not as heavy as the title might suggest! While these resources might not answer your question directly, it might provide a spring board to other solutions.
More specifically, which libraries are you using to write the png and tif files - you mention they are homebrew, but how custom are they exactly? Postprocessing the images in an image manipulation program (such as ImageMagick or dcraw) might allow you to inject this information into the header more successfully.
Sorry, I don't have any specific answers, but maybe something that will point you a bit further in the right direction...
As a GNU/Linux user, you’ll want to consider DispcalGUI – http://dispcalgui.hoech.net/ – a GNOME-based GUI that centralizes color management, ICC profile management, and (crucially for your case) device calibration. It can talk to well-known pro- and mid-level hardware, e.g, i1, X-Rite, Spyder, etc.
But before you get into that – you say you are generating your files to spec; are you validating your output using a test suite specific to the format in question? If not, here are three to get you started:
imagetestsuite supports the well-known formats: https://code.google.com/p/imagetestsuite/w/list?can=1&q=
The Luminous* test suite is a JIRA plugin, if that’s your thing: https://marketplace.atlassian.com/plugins/com.luminouslead.plugin.jira.testsuite.LuminousTestSuite
FLOSS Decoder implementations often have one you can use, i.e. OpenJPEG – https://code.google.com/p/openjpeg/wiki/TestSuiteDocumentation
But even barring all of those, it seems like your problem is with embedded ICC data – which is two specs in one. First, there’s the host image-file format, and they all handle embedding differently (meaning the ICC data will likely look totally different when embedded in a TIFF than, say, a JPEG or WebP file). Second, there is the ICC spec itself. It is documented here: http://color.org/v4spec.xalter – and you may also want to look at the source for the aforementioned dispcalGUI, which includes a very legible and hackable ICC profile class in Python: http://sourceforge.net/p/dispcalgui/code/HEAD/tree/trunk/dispcalGUI/ICCProfile.py
Full disclosure: I have contributed to that very ICC profile class, to which I just linked in that last ¶
That’s the basics (many of which you have no doubt covered)... beyond that, if you post more information about what exactly is going wrong, I’d be interested to look it over. Good luck with it either way.
* NB. This project is unrelated to the long-standing photography website, “the Luminous Landscape”