We review the two-round statically-secure MPC protocol of [3], and intuitively motivate its construction from smaller building blocks. Then we consider the problems in making this protocol adaptively-secure, and present a proposed solution that slightly modifies the protocol to overcome these problems. In the process, we introduce the notion of “Deniable Obfuscation”, as an extension of Deniabl...

Deniable encryption is an important cryptographic primitive, essential in all cryptographic protocols where a coercive adversary comes to play with high potential. Deniable encryption plays a key role in the internet/electronic voting, electronic bidding, electronic auctions and secure multiparty computation. In this study a practical efficient receiver deniable encryption scheme based on BCP c...

A deniable cryptosystem allows a sender and a receiver to communicate over an insecure channel in such a way that the communication is still secure even if the adversary can threaten the parties into revealing their internal states after the execution of the protocol. This is done by allowing the parties to change their internal state to make it look like a given ciphertext decrypts to a messag...

We examine the security requirements for creating a Deniable File System (DFS), and the efficacy with which the TrueCrypt disk-encryption software meets those requirements. We find that the Windows Vista operating system itself, Microsoft Word, and Google Desktop all compromise the deniability of a TrueCrypt DFS. While staged in the context of TrueCrypt, our research highlights several fundamen...

In a proxy signature scheme, one original signer delegates a proxy signer to sign messages on behalf of the original signer. When the proxy signature is created, the proxy signer generates valid proxy signatures on behalf of the original signer. Based on Cha and Cheon’s ID-based signature scheme, a model of designated-verifier proxy signature scheme from the bilinear pairing is proposed. The pr...

Proxy blind signature, which combines the properties of both proxy signature and blind signature, is useful in e-cash and e-commerce. In this paper, we present a verifiable self-certified public key scheme and a proxy blind signature scheme using the verifiable self-certified public key. The self-certified public key has an advantage which can withstand public key substitution attacks. As far a...

Deniable encryption (Canetti et al. CRYPTO ’97) is an intriguing primitive that provides a security guarantee against not only eavesdropping attacks as required by semantic security, but also stronger coercion attacks performed after the fact. The concept of deniability has later demonstrated useful and powerful in many other contexts, such as leakage resilience, adaptive security of protocols,...

Data confidentiality can be effectively preserved through encryption. In certain situations, this is inadequate, as users may be coerced into disclosing their decryption keys. In this case, the data must be hidden so that its very existence can be denied. Steganographic techniques and deniable encryption algorithms have been devised to address this specific problem. Given the recent proliferati...