Please do not trust us.


End-to-end encryption and metadata obfuscation.


Avoidance and obfuscation of metadata.

Hero Qabel


Usability and privacy combined.


Metadata is data about data. Alongside the actual content — the user data such as the content of a document, for example — metadata such as file size, date of creation and file type are associated with the file. In abstract terms, metadata is also information which we encounter in our day-to-day lives completely independently from technology. The where and when of an appointment, the whence and whither of a journey, the who with whom of a conversation. This information allows us to assess everyday situations, to reach conclusions about people's behaviour in specific circumstances with a certain degree of probability and even to extrapolate the relationships between several people from their behaviour. Hence, metadata has a lot to do with experience and logic.

Qabel Image Metadata

The illustration clarifies what conclusions metadata makes possible, particularly in combination. In this example, Eve only knows about the circumstances of the meeting and a few of Alice and Bob's characteristics. Just by combining this metadata and without knowing the actual content of the conversation, Eve can deduce the probable reason for Alice and Bob meeting. Try it for yourself.

Metadata obfuscation

The obfuscation of metadata is not a purely technical exercise. A metadata cannot be assessed and obfuscated in isolation per se, but rather must always be considered in a particular scenario. So the question is not "Which metadata are obfuscated?", but rather "Which metadata are obfuscated from whom?".

How does metadata obfuscation work?

In principle, metadata obfuscation puts you on the wrong track. If, for example, you want to send an image and you want to obfuscate the metadata about the file size from your server operator then the file size needs to be artificially modified. The file is therefore augmented with filler before sending in order to make it larger, then split into small chunks and finally sent in separate parts. The steps are then only reversed upon receipt by the recipient. Similar principles can also be used for file type, date, sender and recipient.

Why is the obfuscation of metadata so important?

At the beginning of 2014, the ex-head of the NSA Hayden said: "We kill people based on metadata". He was referring to terrorists, but this sentence makes it very clear how important metadata is and what it reveals about each one of us. Just think about whether you really don't mind your cloud service, the government or criminals knowing who you had email exchanges with in the last month, when you did so, and where you were at the time. Now think about how much power someone who has this data for not only you but for several million people holds.

Metadata avoidance and obfuscation with Qabel

Right from the launch of the platform with the release in March 2016 and the first Qabel Box services, much of the metadata which would normally accrue is avoided and metadata such as file names and the file type is obfuscated. The stated aim of the platform, however, is to comprehensively obfuscate the metadata that accrues. The first phase therefore also serves as a field test for gaining sufficient knowledge for the further development of Qabel.