Biblio

Network covert timing channel(NCTC) is a process of transmitting hidden information by means of inter-packet delay (IPD) of legitimate network traffic. Their ability to evade traditional security policies makes NCTCs a grave security concern. However, a robust method that can be used to detect a large number of NCTCs is missing. In this paper, a NCTC detection method based on chaos theory and threshold secret sharing is proposed. Our method uses chaos theory to reconstruct a high-dimensional phase space from one-dimensional time series and extract the unique and stable channel traits. Then, a channel identifier is constructed using the secret reconstruction strategy from threshold secret sharing to realize the mapping of the channel features to channel identifiers. Experimental results show that the approach can detect varieties of NCTCs with a guaranteed true positive rate and greatly improve the versatility and robustness.

Covert operations involving clandestine dealings and communication through cryptic and hidden messages have existed since time immemorial. While these do have a negative connotation, they have had their fair share of use in situations and applications beneficial to society in general. A "Dead Drop" is one such method of espionage trade craft used to physically exchange items or information between two individuals using a secret rendezvous point. With a "Dead Drop", to maintain operational security, the exchange itself is asynchronous. Information hiding in the slack space is one modern technique that has been used extensively. Slack space is the unused space within the last block allocated to a stored file. However, hiding in slack space operates under significant constraints with little resilience and fault tolerance. In this paper, we propose FROST – a novel asynchronous "Digital Dead Drop" robust to detection and data loss with tunable fault tolerance. Fault tolerance is a critical attribute of a secure and robust system design. Through extensive validation of FROST prototype implementation on Ubuntu Linux, we confirm the performance and robustness of the proposed digital dead drop to detection and data loss. We verify the recoverability of the secret message under various operating conditions ranging from block corruption and drive de-fragmentation to growing existing files on the target drive.

The threshold secret sharing technique has been used extensively in cryptography. This technique is used for splitting secrets into shares and distributing the shares in a network to provide protection against attacks and to reduce the possibility of loss of information. In this paper, a new approach is introduced to enhance communication security among the nodes in a network based on the threshold secret sharing technique and traditional symmetric key management. The proposed scheme aims to enhance security of symmetric key distribution in a network. In the proposed scheme, key distribution is online which means key management is conducted whenever a message needs to be communicated. The basic idea is encrypting a message with a key (the secret) at the sender, then splitting the key into shares and sending the shares from different paths to the destination. Furthermore, a Pre-Distributed Shared Key scheme is utilized for more secure transmissions of the secret’s shares. The proposed scheme, with the exception of some offline management by the network controller, is distributed, i.e., the symmetric key setups and the determination of the communication paths is performed in the nodes. This approach enhances communication security among the nodes in a network that operates in hostile environments. The cost and security analyses of the proposed scheme are provided.