Confidentiality

In general, AeroFS clients and servers encrypt the communication via RSA with a strong 2048-bit key. On the LAN, clients communicate directly without going through the provider's server. Only if you use a server running on a root server on the Internet team, will your data ever leave its native network. Your data will remain completely under your control at all times; under normal circumstances, the people at AeroFS never get to see your data.

An exception is communication between two clients that reside behind firewalls and sync via the Internet. In this case, the server at zephyr.aerofs.com acts as a relay [7] because direct communication might not be possible. However, because the data transfer is encrypted from end to end, AeroFS at least cannot view the transferred data.

Android App with Weaknesses

To give users access to data on the road without a PC, AeroFS also offers an app for Android [8]. You will find it on Google Play as a free download. After installation, you need to enter your AeroFS account data to see your own data stored in your own cloud (Figure 4).

Figure 4: The AeroFS app for Android is still very limited in its feature set and only allows users to download online data.

The app is still very limited in its functionality: So far, you can only browse your AeroFS upload and download files. The app even occasionally fails, outputting an error message (Figure 5). Uploading and managing files are not options.

Figure 5: Even attempts to download small text files from your own Team Server might provoke unexplained error messages.

Conclusions

AeroFS's claim to fame is "Private file sync & share, made easy." Measured against this, the service fulfills its self-assigned task. The installation of the client is a breeze, thanks to DEB packages and setups for all common systems. Also, the setup is limited to entering an email address and specifying a password. A Team Server can be installed by a non-expert without much effort.

However, compared with Dropbox or other cloud storage solutions, you have to live with limitations, such as the lack of a web front end that lets you view your data. Also, the AeroFS Android app needs a good deal of attention.