Secure transfer of measurement data in open systems Luigi Lo Iacono a, * , Christoph Ruland a , Norbert Zisky b a Institute for Data Communications Systems, University of Siegen, Ho ¨lderlinstrasse 3, D-56078 Siegen, Germany b Physikalisch-Technische Bundesanstalt (PTB), Abbestrasse 2-12, D-10587 Berlin, Germany Available online 13 September 2005 Abstract The liberalization of different markets which are liable to legal metrology accelerates the need for transferring measuring data over open networks. This increases the involvement of communication technology in measuring systems and raises new security threats in legal metrology. The goal of the SELMA (Secure ELectronic Measurement dAta exchange) project is to create technical procedures according to legal requirements which ensure the secure transfer of measured energy data from decentralized meters to the authorized users via open networks. This paper gives an overall view of the research project SELMA and the developed concepts and technologies. The security architecture is presented and the standards and interfaces are described which were specified and afterwards used to implement and deploy a large-scale field trial. SELMA has developed a security architecture to establish trust in the electronic transfer of data from the meter to data acquisition systems and further to the customers. The introduced security mechanisms are based on asymmetric cryptography and more specifically on digital signatures that enable the signed measurement data to be verified and authenticated in conjunction with a suitable key management. Particular security units have been created that contain the necessary security mechanisms. The SELMA architecture represents a best practice solution of strong cryptographic mechanisms to secure a wide range of metrology applications and is compatible with appropriate European directives and guidelines. D 2005 Elsevier B.V. All rights reserved. Keywords: Secure data transfer; Legal metrology; Digital signatures; SELMA 1. Introduction and motivation The goal of legal metrology is to ensure the quality and accuracy of measurements made in the course of e.g. commercial transactions. The liberalization of different markets, which are liable to legal metrology, accelerates the need for transferring measuring data over open networks. This increases the involvement of communication technology in measuring systems and raises new security threats in legal metrology. Generally, the exchange of sensitive data using open communication channels leads also to increased and novel threats. Large damages to network systems or whole infrastructures could be caused by direct attacks to single devices, IT systems or communica- 0920-5489/$ - see front matter D 2005 Elsevier B.V. All rights reserved. doi:10.1016/j.csi.2005.07.010 * Corresponding author. E-mail addresses: luigi.lo-iacono@uni-siegen.de (L. Lo Iacono), christoph.ruland@uni-siegen.de (C. Ruland), norbert.zisky@ptb.de (N. Zisky). Computer Standards & Interfaces 28 (2006) 311– 326 www.elsevier.com/locate/csi