Although cloud services become more and more popular, security concerns of the customers prevent a stronger adoption. Customers are mainly afraid of data leakage and loss of data. In this talk, several cryptographic mechanisms are explained that may help to protect the user against these aforementioned risks. With respect to the risk of data leakage, the best way would be to intrinsically protect the data by encrypting it. However, this usually prevents that the cloud provider who should not know the decryption key can process the data any further, e. g., to execute search queries for the user. In the first part of the talk, I will explain special types of encryption schemes that enable the cloud provider to “blindly” execute on behalf of the user certain operations on the data without revealing its content. In the second part of the talk, I address the risk of data loss. In particular, I will explain cryptographic protocols that allow for efficiently verifying whether the outsourced data is still stored by the cloud provider without the need to download the whole data.
Frederik Armknecht is an assistant professor for cryptography at the University of Mannheim, Germany, since 2010. His research interests include cloud security, lightweight cryptography, and security for cyber-physical systems. He has numerous publications on the top conferences in cryptography/IT-security and has been involved into several patents. Moreover, he was one of the initiators of TrustED, the international workshop on trustworthy embedded devices. From 2006-2007, he worked as a Research Staff member in the Mobile Internet group at NEC Europe Ltd. in Heidelberg focusing on cryptographic and security issues in various kinds of networks. From 2007-2008, he worked as a postdoc at the Ruhr-University Bochum, Germany where he conducted research on provable security and operating on encrypted data. From 2008-2009, he was an assistant professor at the Ruhr-University Bochum, where he headed the group for cryptographic methods and security models. From 2009-2010, he was a visiting professor at Technische Universität Darmstadt, Germany.