Simple CSRF token using HMAC for authentication and integrity.
What does this do?
This is intended as an alternative to Microsoft's AntiForgeryToken, but not necessarily a drop-in replacement.
Why would I use this?
As you may or may not know, validating an AntiForgeryToken requires that the MachineKey be synchronized across all servers. This might not be desirable or possible from a configuration standpoint, and crypto can be computationally expensive. This library generates a token that will work across different or random machine keys and should not require a lot of power to validate.
The token format looks something like this:
(random data)(split)(userId)(split)(expiryTime)(split)(hmac of previous data)
Finally, the token is converted to Base64 so it can be passed through however you like as a developer. The value userId may not map to an userId in your application. It could be a user name, Guid, etc.
This package allows you to create an instance or simply invoke statically. Here's an example of each:
string token = AntiCSRFToken.GenerateToken(username, key); bool isValid = AntiCSRFToken.ValidateToken(token, key, username);
var instance = new AntiCSRF(); string token = instance.GenerateToken(username, key); bool isValid = instance.ValidateToken(token, key, username);
Each method can also accept a discrete configuration as a parameter, represented by the AntiCSRFConfig class. This allows you to set the token expiry time, HMAC algorithm, split character, or disable Base64 conversion.
I welcome any and all suggestions or improvements to the codebase. Thanks for dropping by and hope you find a good use for this library!