The Azure Function documentation is clear on using Host and/or Function keys to provide "api key" authorization. However, I can't find anything that indicates if there is a limit on how many keys can be created on a particular function or function app.
I would like to share a unique key with each tenant in a multi-tenant application so I can update or revoke them on a per-tenant basis. However, this approach will only work if I am able to generate hundreds (or potentially thousands) of keys.
Can anyone confirm any known limits on the number of keys that can be generated on a function app?
There aren't any strict limits imposed by the runtime, but we can't make any guarantees that this would be performant at scale.
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The use case is a user has a metadata that needs to be encrypted so when they sign-in a protected and stored object "encrypted" will be "checked" to verify the object information coming in plaintext is equal to what is in the encrypted object.
The question is, is it more appropriate in an Azure Key Vault to give each and every user a key with public and private key ability. Or, just use a single key that will encrypt the object that is stored and just un-sign/decrypt the object when it is accessed.
To me, the object is what is necessary to be encrypted and doesn't really relate to how the key is encrypted hence a universal 1 key to many approach.
The other approach makes sense too but I would have to create a hell of a lot of keys in order to facilitate such an approach. Is 1000's or millions of keys resulting in a key per each user appropriate?
What are the advantages or disadvantages of each other.
I think the same practice would apply to JWT token signing.
I think its better to have one key and on a regular basis rotate the key.
For example, like they do in ASP.NET Core Data Protection API (I know you are using node) where they every 90 days (by default) replace the current key with a new one, and the old one is still kept to allow decryption of old data. In .NET they call this the key-ring, that hold many keys.
I did blog about this here.
Also, do be aware that using some SDK's with Azure Key Vault, they try to download all secrets at start-up, one-by-one. That can be quite a time consuming if you have many secrets.
I want to use Cosmos db with c# code. A really important point is that data should stay encrypted at any point. So, as I understood, once the data on the server, it's automaticaly encrypted by azure by the encryption-at-rest. But during the transportation, do I have to use certificate or it's automatically encrypted. I used this link to manage the database https://learn.microsoft.com/fr-fr/azure/cosmos-db/create-sql-api-dotnet. My question is finally : Is there any risk of safety if I just follow this tutorial?
Thanks.
I think that's a great starting point.
Just one note, your data is only as secure as the access keys to the account so, on top encryption at rest and in transit, the Access Key is probably the most sensitive piece of information you need to protect.
My advice is to use a KeyVault to store the database access key rather than define them as environment variables. Combined with Managed Identity, your key will never leave the confines of the azure portal which makes it the most secure option. I'm not sure how you plan on deploying your code but more times than not I've seen those keys encoded in source code or in some configuration file that ends up exposed.
A while ago I wrote a step-by-step tutorial describing how to implement this. You can find my article here
I would suggest you to follow the instructions mentioned in here, and not even using access keys, because if they are accidentally exposed, no matter that you have stored them in a Key Vault or not, your database is out there. Besides, if you want to use access keys, it is recommended to change the access keys periodically, which then you need to make this automatic and known to your key vault, here it is described how you could automate that.
Is there any merit in creating an obscure azure storage account name by using the max number of random chars/nums that is allowed when creating one from the portal?
I know that they are still going to be publicly visible and accessible with the keys but is there any benefit in this? Admin is going to be trickier from the portal having accounts with randomly generated names naturally. Is there such a malicious practice of "scanning" storage account names to find ones that exist to potential abuse or is there mechanisms to prevent that? I am aware that obfuscation does not equal security and only means to delay and not prevent but I can't see any other way to secure a storage account to a specific IP address/range presently.
Is this something you would/wouldn't recommend to do in practice? Am I just being overly cautious and in fact the access keys on their own are indeed a good level of security.
I am no security expert, but IMHO, you are being over cautious... with the name, that is..
Having said that, it is always a good security policy to rotate the access keys at a given frequency. The very reason why these services support primary and secondary access keys is to enable the scenario for key rotation... and think of it as similar to systems enforcing a user to change their password every X days.
The frequency could be anything you prefer, or your in house security experts suggests as acceptable.
Although initially needs effort investment, automating the key rotation process is obviously best.
I want to make an option such that I can issue 3rd part developers access to my data and to do so, similar to the following: https://docs.sharedcount.com/, I want to create a system wherein those developers are provided an API key for which the consumption count can be monitored
Came through Waterlock but does not look like it has this feature: http://waterlock.ninja/
Curious, what would be the best approach to implement API keywords for a Sail.js app?
Sails makes this incredibly easy by use of policies. When a user signs up, assign them an API key, and then create a policy that checks the params for a valid API key -- i.e. req.param('APIKey') -- and deny access if one is not found.
I'm creating an application that will be hosted in Azure. In this application, users will be able to upload their own content. They will also be able to configure a list of other trusted app users who will be able to read their files. I'm trying to figure out how to architect the storage.
I think that I'll create a storage container named after each user's application ID, and they will be able to upload files there. My question relates to how to grant read access to all files to which a user should have access. I've been reading about shared access signatures and they seem like they could be a great fit for what I'm trying to achieve. But, I'm evaluating the most efficient way to grant access to users. I think that Stored access policies might be useful. But specifically:
Can I use one shared access signature (or stored access policy) to grant a user access to multiple containers? I've found one piece of information which I think is very relevant:
http://msdn.microsoft.com/en-us/library/windowsazure/ee393341.aspx
"A container, queue, or table can include up to 5 stored access policies. Each policy can be used by any number of shared access signatures."
But I'm not sure if I'm understanding that correctly. If a user is connected to 20 other people, can I grant him or her access to twenty specific containers? Of course, I could generate twenty individual stored access policies, but that doesn't seem very efficient, and when they first log in, I plan to show a summary of content from all of their other trusted app users, which would equate to demanding 20 signatures at once (if I understand correctly).
Thanks for any suggestions...
-Ben
Since you are going to have a container per user (for now I'll equate a user with what you called a user application ID), that means you'll have a storage account that can contain many different containers for many users. If you want to have the application have the ability to upload to only one specific container while reading from many two options come to mind.
First: Create a API that lives somewhere that handles all the requests. Behind the API your code will have full access to entire storage account so your business logic will determine what they do and do not have access to. The upside of this is that you don't have to create Shared Access Signatures (SAS) at all. Your app only knows how to talk to the API. You can even combine the data that they can see in that summary of content by doing parallel calls to get contents from the various containers from a single call from the application. The downside is that you are now hosting this API service which has to broker ALL of these calls. You'd still need the API service to generate SAS if you go that route, but it would only be needed to generate the SAS and the client applications would make the calls directly with the Windows Azure storage service bearing the load which will reduce the resources you actually need.
Second: Go the SAS route and generate SAS as needed, but this will get a bit tricky.
You can only create up to five Stored Access Policies on each container. For one of these five you create one policy for the "owner" of the container which gives them Read and write permissions. Now, since you are allowing folks to give read permissions to other folks you'll run into the policy count limit unless you reuse the same policy for Read, but then you won't be able to revoke it if the user removes someone from their "trusted" list of readers. For example, if I gave permissions to both Bob and James to my container and they are both handed a copy of the Read SAS, if I needed to remove Bob I'd have to cancel the Read Policy they shared and reissue a new Read SAS to James. That's not really that bad of an issue though as the app can detect when it no longer has permissions and ask for the renewed SAS.
In any case you still kind of want the policies to be short lived. If I removed Bob from my trusted readers I'd pretty much want him cut off immediately. This means you'll be going back to get a renewed SAS quite a bit and recreating the signed access signature which reduces the usefulness of the signed access policies. This really depends on your stomach of how long you were planning on allowing the policy to live and how quickly you'd want someone cut off if they were "untrusted".
Now, a better option could be that you create Ad-hoc signatures. You can have as many Ad-hoc signatures as you want actually, but they can't be revoked and can at most last one hour. Since you'd make them short lived the length or lack of revocation shouldn't be an issue. Going that route will mean that you'd be having the application come back to get them as needed, but given what I mentioned above about when someone is removed and you want the SAS to run out this may not be a big deal. As you pointed out though, this does increase the complexity of things because you're generating a lot of SASs; however, with these being ad-hoc you don't really need to track them.
If you were going to go the SAS route I'd suggest that your API be generating the ad-hoc ones as needed. They shouldn't last more than a few minutes as people can have their permissions to a container removed and all you are trying to do is reduce the load on hosted service for actually doing the upload and download. Again, all the logic for handling what containers someone can see is still in your API service and the applications just get signatures they can use for small periods of time.