Crypto in the Cloud presented at Troopers 2015

by Frederik Armknecht,

Summary : 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.