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how to prevent querystring values from being visible

We have an application which is destined for https so the data being transmitted is protected (or should I say as protected as need be) I would like to know about protecting/hiding (or similar) queryString values. Its a jQuery/Javascript front end which communicates using a mixture of GET and POST with the database via classic ASP web services. The web services sends JSON back to the client.
I realize the front end code could be changed so everything is passed using POST however the application is finished and tested ready to deploy. There are some key values that are being passed in the querystring which should not have been. Is it possible to make it so the querystring values can not be inspected or sniffed. The URL and querystring together will provide a direct link to the raw JSON. We would like to prevent this. Perhaps there is some jQuery/AJAX feature which can be explored. Perhaps some server IIS level tactic? I guess the sniffing occur before the request gets the the server where the webservice sites therefore some server/IIS level tactic is not an option.
Any ideas/advice would be great, thank you.

You can use HTTP headers to send data to the server that is slightly less visible, but can still be detected using more advanced developer tools and loggers. For example, this answer descibes using jQuery/Javascript (as you've asked) to send data without using QueryString.
You can't really prevent the client from being able to trace these details though.
The solution I personally suggest to you is to look into session state. By scoping a valid data response to a certain session state, and returning null when the state is invalid or expired, you can limit access to the data. This could be after just 1 time its been retrieved. This strategy would involve a generation of a token or code that is passed out from your server at an earlier stage, and used when asking for the data in question.

Another alternative is to either use SSL or encrypt your data and drop it into a posted control such as a text input box. Microsoft adopted a similar process for their VIEWSTATE within ASP.NET.

webapi backend with pure javascript frontend, security

So now I am pretty much sold to the idea of having pure html+js front end where all processing happens at client side browser and the backend provides all the data in JSON/xml/other format and so on.
Here's the dilemma,
For authentication, I am using OAuth2 Bearer token which gets generated when user authenticate using username and password (for e.g. at login stage).
There is an extra security for which clientside application (i.e.a front end web server or mobile app) that is making request to this WebAPI. When it makes the initial request, it passes "client_id " and "client_secret" to make sure the client is app is authorized to make this request to back end server.
In traditional .NET way I would store the encrypted clientid and key in web.config and my C# (Or VB.NET) code would retrieve it and send it over SSL to the server. So in the manner the client_id and client_secret is not exposed in rendered HTML (for e.g.) to the client side browser.
In pure javascript environment how can I secure my client_id and client_secret (or any other sensitive data for that matter)?
Thanks

I don't think you can secure your "secrets".
HTML5/JS code is pure text, anyone with a text editor can see it. What people normally try to do is obfuscate their code by using javascript minifiers/compressors; see here for a good discussion. The practice is called Security through Obscurity. But note that obfuscation is not security. Given time and effort, a determined "hacker" will eventually find your secrets. Another step you can take to deter, delay and frustrate such attacks is to spread bits of your secrets in the code, in different modules, etc. Having said that, you'll need to write code to assemble them at some point, so again, no real security.
I have a similar problem because I wanted to use a "shared secret" with the server so I can hash my client requests such that they are tamper-proof and can't be recreated without the attacher knowing the shared secret. Unfortunately I had to give up on the idea, since I realised I couldn't keep it secret enough.

How can you secure a JavaScript application's API calls?

I have a JavaScript application.
It's built with jQuery.
It uses $.get() to pull JSON data from a server, and uses the data to load a puzzle.
I want to distribute the JavaScript application to clients, and make it easy for them to install.
I'd like it to simply give them a JavaScript block they can drop into their page, and it will interact with my API.
I'm not passing sensitive data, any my API is protecting the database from SQL injection, etc.
I just want to try to prevent unauthorized use of my API, and I can't think of a way to do that with JavaScript, since anyone with a DOM inspector can scrape any credentials from any variables or can monitor any server traffic POST or GET data...
Would it be possible to authenticate the referrer on the other side?
I know that's not bulletproof, but it's not sensitive data. I just want to reduce the unauthorized use as much as possible..
Any ideas?
note: I know obfuscating an API key or something is futile, I'm wondering what other controls I could put in place other than a traditional key to identify the caller to the API.. I have full control over the API itself so I could do anything on that side of things...

JavaScript authentication has holes
With JavaScript, just about any authentication system is going to have holes, simply because the code runs directly in the browser and can be seen by anyone (as can the network calls). So there are a couple of things you can try, depending on your situation.
IP whitelisting
If you are distributing this application to a small subset of clients, and you know exactly where they will be accessing it from, you could use IP whitelisting. This really is the only way to completely secure the API. However this method is very cumbersome, since with every new client you have to update the API whitelist, and considering what you're talking about here probably not what you're looking for (but I mention it just because it is a possibility).
Access tokens
Another method is access tokens. This is a common method used by sites such as Facebook. There are two methods to do this. One is to just give each client a secret key. You can have the same secret key for everyone, but this is not very secure. Having a different secret key for everyone allows you to not only track usage, but also revoke access privs if necessary.
The first method for access tokens is to just give it inside the JS client. However this means that anyone who looks at the source will be able to access your key, and make requests using it.
The second method is to have the secret key stored somewhere on the SERVER of the website where your client runs. This server can then make a server-to-server call using that key to obtain a temporary session token. People will still be able to access the temporary session token via the front-end, but they will have to access this site first in order to get it (this allows you to pass off responsibility for handling this to the website operator) and the token will eventually expire. However this means there needs to be some server-side code, and the app won't just be a drag and drop thing.
For the method given above you can also look into things like OAuth, to avoid re-inventing the wheel.
Whitelist hard-cap
Another possible thing using IPs is to set a hard-cap on either how often or how much per day a specific IP can hit the whitelist. Though you may run into problems with users who REALLY like the puzzles, this will prevent some of the potential abuse.

Public facing Authentication mechanisms for REST

I am designing a new service that would enable 'customers' to register and pay a per-use type fee for particular searches they perform. This service would be exposed using a RESTFul and SOAP interface. Typically the web service would integrate with the customer's website and then be exposed to the 'public' where anyone would be able to use the customer's website and take advantage of my web service features (which the customer would pay for but have full control of moderating the requests so they don't get charged too much).
I want to design the service that optimises the integration to make it as simple as possible. The web service API will change so creating an internal proxy to expose the web service to the public in some cases is too much of a detractor for customers. So the issue as I see it is creating a web service that balances authentication, security and integration.
Ideal
Not use OAuth
Avoid forcing the customer to create an internal proxy which re-exposes the same web service API I have already.
Be secure (token username/pass whatever and ssl)
Embed a javascript library in customer website - This would be a client Javascript library to make integration steps even easier.
The Javascript library would need to be secure enough so that the public wouldn't be able to simply grab credentials and re-purpose it themselves
Not be too hacky, if possible, so the web service doesn't have to be re-built if Firefox 87 comes out (to be released in as many minutes) and decides to fubar it.
It seems that some kinda of 3-way authentication process is needed for this to work, i.e. authenticates a particular client (in the public), the web service (the customer) and the web service.
Has anyone implemented something kind of similar and how did they tackle a situation like this?
I also understand there is a balance between what can be done, and what would violate cross-domain security, so perhaps the entire web service might be exposed by another GET only interface which would return JSONP data.
/** Addendum **/
I have since discovered a web service that does what I'm looking after. However, I am not confident I understand the implementation details entirely. So perhaps someone could also elaborate on my thinking.
The web service I discovered seems to host the Javascript on the service side. The customer would then integrate their website with the service side by including the Javascript in a script tag, but supplies a key to do so i.e.
Somehow if I add the script to my website it doesn't work. So somewhere along the line the token must be registered to a particular customer domain, and the 'client-lib.js' is actually a servlet or something similar which can somehow detect that the user from the 'public' coming in has actually originated from the 'customer' domain.
Is my thinking right? Is there some kind of http header that can be used this way? Is that safe?
Cheers

First of all - let me provide you a link to another SO question which I answered yesterday - as it gives a pretty extensive answer to a similar question-set.
I am assuming that you are going to charge the owner of the site from which the search is made, and not care so much who the individual user is who makes the search. If that's incorrect, please clarify and I will update my answer accordingly.
Clearly, in any such case, the first and foremost thing you need to do is to make sure you know which client this is on each request. And - as you said, you also want to make sure you're protecting yourself from cross-site attacks and people stealing your user's keys.
What you might consider would be the following:
Create a private key on your side - which only your service knows.
Whenever a new consumer site creates an account with you, create a new shared key which only you and they will know. I suggest creating this key by using your private key as a password, and encrypting some kind of identifier which will let you identify this particular user.
As part of your registration process, make the consumer site tell you what URI they will be using your scripts on.
Now - the way that you both do your tracking and authentication becomes fairly simple.
You mentioned providing a JS library which won't need to update every time FF updates. I suggest building that library using jQuery, or another, similarly supported cross-browser JS foundational library - and letting that wrap your AJAX.
When the client site requests your script, however, have them provide you something like:
http://www.yourdomain.com/scripts/library.js?key={shared key}
On your side, when you receive this request, check the following:
When you decrypt their shared key using your private key, you should not get gibberish. If you do - it's because their key has been altered in some way - and is not valid. This should result in a 401: Unauthorized error.
Once you decrypt the key and know which client site this is (because that's what the key contains) - check to make sure that the request is coming from the same URI that client registered with. This now protects you from someone stealing their key and injecting it into a different website.
As long as the above matches, let them download the file.
Now - when you serve the JS file, you can do so in a way that injects the key into that file - and therefore it has access to their shared key. On each of your AJAX requests, include that key so that you can identify which client this request is coming from again. In a RESTful environment, there shouldn't really be sessions - so you need this level of authentication on each post. I suggest including it as a cookie.
On your server-side - simply repeat the checks of their key on each subsequent request - and voila - you've built yourself some fairly tight security without a lot of overhead.
That said - if you expect a lot of traffic - you may want to come back to this and explore more deep security processes in the future, as rolling your own security matrix can leave unexpected holes. However - it is a good start and will get you off the ground.
Feel free to ask any questions if you need, and I will try to update my answer accordingly.

The best way to go about it is something like this (taking that you want to use javascript hosted on your server and make the include part as simple as it can be):
*user registers on your website and he receives a token for his domain
*the user can include a js file pointing to your server
the js file will be something like:
<script type="text/javascript" src="http://your.server.com/js.php?token=###&widget=xxx"></script>
or
<script type="text/javascript" src="http://your.server.com/js.js?token=###&widget=xxx"></script>
if you will use a .htaccess to redirect
*in the php file check if the token matches the requests domain, if yes echo out the js lib, if not throw a error or something
*in the js you will need to build some ajax calls to your service and stuff to manipulate the HTML (create a widget holder,show some data, etc.)
*also all the calls should have the token, and again you can use the same logic to check if token==server address
EDIT:
The REFERER is sent by the client's browser as part of the HTTP protocol, and is therefore unreliable indeed.
If you want to verify if a request is coming from your site, well you can't, but you can verify the user has been to your site and/or is authenticated. Cookies are sent in AJAX requests so you can rely on that. But this means you need to use something like oAuth
If you want to use this method, you should still check the referrer as well to prevent CSRF en.wikipedia.org/wiki/Cross-site_request_forgery
Ideally you should use a unique token per session per user (per request if you're paranoid) to prevent CSRF attacks. Checking the referrer is just security by obfuscation and not quite a real solution.

Web services API Keys and Ajax - Securing the Key

This is probably a generic security question, but I thought I'd ask in the realm of what I'm developing.
The scenario is: A web service (WCF Web Api) that uses an API Key to validate and tell me who the user is, and a mix of jQuery and application on the front ends.
On the one hand, the traffic can be https so it cannot be inspected, but if I use the same key per user (say a guid), and I am using it in both then there's the chance it could be taken and someone could impersonate the user.
If I implement something akin to OAuth, then a user and a per-app key is generated, and that could work - but still for the jQuery side I would need the app API key in the javascript.
This would only be a problem if someone was on the actual computer and did a view-source.
What should I do?
md5 or encrypt the key somehow?
Put the key in a session variable, then when using ajax retrieve it?
Get over it, it's not that big a deal/problem.
I'm sure it's probably a common problem - so any pointers would be welcome.
To make this clearer - this is my API I have written that I am querying against, not a google, etc. So I can do per session tokens, etc, I'm just trying to work out the best way to secure the client side tokens/keys that I would use.
I'm being a bit overly cautious here, but just using this to learn.

(I suggest tagging this post "security".)
First, you should be clear about what you're protecting against. Can you trust the client at all? A crafty user could stick a Greasemonkey script on your page and call exactly the code that your UI calls to send requests. Hiding everything in a Javascript closure only means you need a debugger; it doesn't make an attack impossible. Firebug can trace HTTPS requests. Also consider a compromised client: is there a keylogger installed? Is the entire system secretly running virtualized so that an attacker can inspect any part of memory at any time at their leisure? Security when you're as exposed as a webapp is is really tricky.
Nonetheless, here are a few things for you to consider:
Consider not actually using keys but rather HMAC hashes of, e.g., a token you give immediately upon authentication.
DOM storage can be a bit harder to poke at than cookies.
Have a look at Google's implementation of OAuth 2 for an example security model. Basically you use tokens that are only valid for a limited time (and perhaps for a single IP address). That way even if the token is intercepted or cloned, it's only valid for a short length of time. Of course you need to be careful about what you do when the token runs out; could an attacker just do the same thing your code does and get a new valid token?
Don't neglect server-side security: even if your client should have checked before submitting the request, check again on the server if the user actually has permission to do what they're asking. In fact, this advice may obviate most of the above.

It depends on how the API key is used. API keys like that provided by Google are tied to the URL of the site originating the request; if you try and use the key on a site with an alternate URL then the service throws and error thus removing the need to protect the key on the client side.
Some basic API's however are tied to a client and can be used across multiple domains, so in this instance I have previously gone with the practice of wrapping this API in server side code and placing some restrictions on how the client can communicate with the local service and protecting the service.
My overall recommendation however would be to apply restrictions on the Web API around how keys can be used and thus removes the complications and necessity of trying to protect them on the client.

How about using jQuery to call server side code that handles communication with the API. If you are using MVC you can call a controller action that can contain the code and API key to hit your service and return a partial view (or even JSON) to your UX. If you are using web forms you could create an aspx page that will do the API communication in the code behind and then write content to the response stream for your UX to consume. Then your UX code can just contain some $.post() or $.load() calls to your server side code and both your API key and endpoint would be protected.

Generally in cases like this though you proxy requests through the server using 'AJAX' which verifies the browser making requests is authorized to do so. If you want to call the service directly from JavaScript, then you need some kind of token system like JSON Web Tokens (JWT) and you'll have to work out cross-domain issues if the service is located somewhere other than the current domain.

see http://blogs.msdn.com/b/rjacobs/archive/2010/06/14/how-to-do-api-key-verification-for-rest-services-in-net-4.aspx for more information
(How to do API Key Verification for REST Services in .NET 4)