Access Control
Purpose based

Purpose based access

Purpose based access control is a way to define access control policies based on the purpose of the data. The GDPR requires that data is only used for the purpose it was collected for. We allow combining purpose based access control with data transformations.

Example

purpose1 := purpose({
	"transformers": [tabular.allow_columns(["name", "age"])]
})

By passing the purpose as an context to an S3 data access request, the data will be transformed before it is returned.

GET /<fileName>?p_purpose=purpose1

Our proxy will automatically determine the data type that is being accessed and apply the correct transformer. In the example above we are assuming the provided access policy is associated with tabular data from a CSV-file for example. By default no data access is allowed and specific purposed allow explicitly certain columns to be accessed. In our example name and age. The transformers we provide are being explained more in detail under the transformer section. If no purpose from the provided context is matching against any policy definition no data will get returned.

Building a purpose graph

We extended the idea of a flat list of policies to allow arbtrary graphs of purposes by specifying the optional specifies property.

purpose1 := purpose({
	"transformers": [tabular.allow_columns(["name", "age"])]
})
 
purpose2 := purpose({
	"specifies": [purpose1],
	"transformers": [tabular.allow_columns(["address"])]
})

This example defines a very simple tree of purposed where the purpose purpose2 is inheriting from purpose1. This means that purpose2 is allowed to access all columns that purpose1 is allowed to access. In addition purpose2 is allowed to access the address column.

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