Tommaso Gagliardoni is a cryptographer, privacy hacktivist, and quantum security expert. He works as a researcher and innovation leader at Swiss-American cybersecurity company Kudelski Security. Tommaso published many influential peer-reviewed papers in the areas of cryptography, quantum computing, security, and privacy, and spoke at many international conferences in these fields. He obtained an M.Sc. in Mathematics at the University of Perugia, Italy, and a PhD at the Technical University of Darmstadt, Germany, with a dissertation on the quantum security of cryptographic primitives. Before joining Kudelski Security, he worked in the Security and Privacy group at IBM Research Zurich.
You may believe traditional storage encryption is enough to protect the privacy of your data at rest, even in untrusted environments. Think twice: Access pattern leakage can, in many cases, reveal sensitive information to an attacker. For example, a malicious cloud provider can still see whether a user performs read or write operations and which part of the data is accessed, even if all of the data is encrypted.
Oblivious Random Access Machines (ORAMs) are cryptographic schemes that hide both data and access patterns. This obfuscation is achieved by making redundant read/write operations and encrypting, re-randomizing, and shuffling the blocks composing the storage layer on every access. The resulting loss of performance is a tradeoff that allows to turn untrusted storage into a trusted one solely via software. However, existing solutions are cumbersome for the user, requiring the storage provider to support the ORAM scheme.
We implemented oramfs: an open source, cloud- and storage-agnostic, resizable ORAM client written in Rust that offers privacy features beyond encryption. In this talk, we look at how a practical ORAM scheme such as PathORAM works, give some background about oramfs, and show how it can be used to protect data resting on untrusted storage.