Body area networks (BANs) consisting of small sensing and computing devices can help to improve medical care and well-being of humans. Obviously, the data recorded in BANs such as vital parameters are personal and should be private. To protect this privacy, such data are usually encrypted when transmitting it over a wireless link. In the past, many cryptographic algorithms and methods for the encryption and decryption of data have been proposed-and most of them have become obsolete. One-time pads (OTPs) were mathematically proven to be secure and impossible to crack. But, for most purposes, OTPs are complicated to handle, because if applied correctly, for each bit of plain text data, another bit of OTP must be available.
Sensors in BANs usually do not generate an enormous amount of data. Hence, also the length of an OTP is not huge. Sustained progress in memory technology makes large amounts of nonvolatile memory available at cheap prices and small sizes. Thus, numerous OTPs can be preinstalled on BAN devices and ensure a long lasting and secure data transmission. In this paper, we present a concept for securing data transmission in BANs by utilizing OTPs. We delineate a system for generation, distribution, and utilization of OTPs in wireless sensor network (WSN) and BAN scenarios, and we show the implementation and evaluation of such a system.