The availability of consumer grade EEG headsets and open EEG hardware platforms makes it easier for everyone to develop a Brain-Computer Interface (BCI). The talk will explain the basics of Electroencephalography (EEG) and how information can be extracted from the Electroencephalogram, which is basically a noise signal. This covers Event Related Potentials (ERP) and their application in common BCI paradigms and biometric schemes. Standard approaches for the experimental setup and for EEG signal processing will be discussed. As an example an EEG based authentication system will be presented that uses the P300 component of the ERP and images as a password. This talk will give an overview of the issues of performance, usability, privacy and security in BCIs and how far the technology is from reading the mind or connecting us to the matrix.