In cryptography, Achterbahn is a synchronous stream cipher algorithm submitted to the eSTREAM Project of the eCRYPT network.
Achterbahn means rollercoaster (in German), though a literal translation of the term would be eight-track, which indicates that the cipher can encrypt eight bit streams in parallel.
Recent analysis showed that attacks are possible if larger frame (packet) lengths are used in a communication protocol.
The ACHTERBAHN-128/80 stream cipher is optimized for hardware applications with restricted resources, such as limited gate count and power consumption.
An implementation of ACHTERBAHN-80 has a design size of only 2188 gate equivalents (Nand-GE) in a standard CMOS technology and delivers a throughput of up to 400 Megabit/s.