Existing software-based data erasure programs can be summarized as following the same one-bit-return protocol: the deletion program performs data erasure and returns either success or failure. However, such a one-bit-return protocol turns the data deletion system into a black box-the user has to trust the outcome but cannot easily verify it. This is especially problematic when the deletion program is encapsulated within a Trusted Platform Module (TPM), and the user has no access to the code inside. In this paper, we present a cryptographic solution that aims to make the data deletion process more transparent and verifiable. In contrast to the conventional black/white assumptions about TPM (i.e., either completely trust or distrust), we introduce a third assumption that sits in between: namely, “trust-but-verify”. Our solution enables a user to verify the correct implementation of two important operations inside a TPM without accessing its source code: i.e., the correct encryption of data and the faithful deletion of the key. Finally, we present a proof-of-concept implementation of the SSE system on a resource-constrained Java card to demonstrate its practical feasibility. To our knowledge, this is the first systematic solution to the secure data deletion problem based on a “trust-but-verify” paradigm, together with a concrete prototype implementation.

Dragonfly is a password authenticated key exchange protocol that has been submitted to the Internet engineering task force as a candidate standard for general internet use. The authors analysed the security of this protocol and devised an attack that is capable of extracting both the session key and password from an honest party. This attack was then implemented and experiments were performed to determine the time‐scale required to successfully complete the attack.

Primary-backup replication enables arbitrary services, which need not be built as deterministic state machines, to be reliable against server crashes. Further, when the primary does not crash, the performance can be close to that of an un-replicated, 1-server system and is arguably far better than what state machine replication can offer. These advantages have made primary-backup replication a widely used technique in commercial provisioning of services, even though the technique assumes that residual software bugs in a server system can lead only to crashes and cannot result in state corruption. This assumption cannot hold against an attacker intent on exploiting vulnerabilities and corrupting the service state when attacks lead to intrusions. This paper presents a system, called FORTRESS, which can encapsulate a primary-backup system and safeguard it from being intruded. At its core, FORTRESS applies proactive obfuscation techniques in a manner appropriate to primary-backup replication and deploys proxy servers for additional defence. Gain in intrusion resilience is shown to be substantial when assessed through analytical evaluations and simulations for a range of attacker scenarios. Further, by implementing two web-based applications, the average performance drop is demonstrated to be in the order of tens of milliseconds even when obfuscation intervals are as small as tens of seconds.