487 research outputs found

    Semantically Secure Anonymity: Foundations of Re-encryption

    Get PDF
    The notion of universal re-encryption is an established primitive used in the design of many anonymity protocols. It allows anyone to randomize a ciphertext without changing its size, without first decrypting it, and without knowing who the receiver is (i.e., not knowing the public key used to create it). By design it prevents the randomized ciphertext from being correlated with the original ciphertext. We revisit and analyze the security foundation of universal re-encryption and show a subtlety in it, namely, that it does not require that the encryption function achieve key anonymity. Recall that the encryption function is different from the re-encryption function. We demonstrate this subtlety by constructing a cryptosystem that satisfies the established definition of a universal cryptosystem but that has an encryption function that does not achieve key anonymity, thereby instantiating the gap in the definition of security of universal re-encryption. We note that the gap in the definition carries over to a set of applications that rely on universal re-encryption, applications in the original paper on universal re-encryption and also follow-on work. This shows that the original definition needs to be corrected and it shows that it had a knock-on effect that negatively impacted security in later work. We then introduce a new definition that includes the properties that are needed for a re-encryption cryptosystem to achieve key anonymity in both the encryption function and the re-encryption function, building on Goldwasser and Micali\u27s semantic security and the original key anonymity notion of Bellare, Boldyreva, Desai, and Pointcheval. Omitting any of the properties in our definition leads to a problem. We also introduce a new generalization of the Decision Diffie-Hellman (DDH) random self-reduction and use it, in turn, to prove that the original ElGamal-based universal cryptosystem of Golle et al is secure under our revised security definition. We apply our new DDH reduction technique to give the first proof in the standard model that ElGamal-based incomparable public keys achieve key anonymity under DDH. We present a novel secure Forward-Anonymous Batch Mix as a new application

    Advances in Information Security and Privacy

    Get PDF
    With the recent pandemic emergency, many people are spending their days in smart working and have increased their use of digital resources for both work and entertainment. The result is that the amount of digital information handled online is dramatically increased, and we can observe a significant increase in the number of attacks, breaches, and hacks. This Special Issue aims to establish the state of the art in protecting information by mitigating information risks. This objective is reached by presenting both surveys on specific topics and original approaches and solutions to specific problems. In total, 16 papers have been published in this Special Issue

    The Cryptographic Imagination

    Get PDF
    Originally published in 1996. In The Cryptographic Imagination, Shawn Rosenheim uses the writings of Edgar Allan Poe to pose a set of questions pertaining to literary genre, cultural modernity, and technology. Rosenheim argues that Poe's cryptographic writing—his essays on cryptography and the short stories that grew out of them—requires that we rethink the relation of poststructural criticism to Poe's texts and, more generally, reconsider the relation of literature to communication. Cryptography serves not only as a template for the language, character, and themes of much of Poe's late fiction (including his creation, the detective story) but also as a "secret history" of literary modernity itself. "Both postwar fiction and literary criticism," the author writes, "are deeply indebted to the rise of cryptography in World War II." Still more surprising, in Rosenheim's view, Poe is not merely a source for such literary instances of cryptography as the codes in Conan Doyle's "The Dancing-Men" or in Jules Verne, but, through his effect on real cryptographers, Poe's writing influenced the outcome of World War II and the development of the Cold War. However unlikely such ideas sound, The Cryptographic Imagination offers compelling evidence that Poe's cryptographic writing clarifies one important avenue by which the twentieth century called itself into being. "The strength of Rosenheim's work extends to a revisionistic understanding of the entirety of literary history (as a repression of cryptography) and then, in a breathtaking shift of register, interlinks Poe's exercises in cryptography with the hyperreality of the CIA, the Cold War, and the Internet. What enables this extensive range of applications is the stipulated tension Rosenheim discerns in the relationship between the forms of the literary imagination and the condition of its mode of production. Cryptography, in this account, names the technology of literary production—the diacritical relationship between decoding and encoding—that the literary imagination dissimulates as hieroglyphics—the hermeneutic relationship between a sign and its content."—Donald E. Pease, Dartmouth Colleg

    Fingerprinting Encrypted Tunnel Endpoints

    Get PDF
    Operating System fingerprinting is a reconnaissance method used by Whitehats and Blackhats alike. Current techniques for fingerprinting do not take into account tunneling protocols, such as IPSec, SSL/TLS, and SSH, which effectively `wrap` network traffic in a ciphertext mantle, thus potentially rendering passive monitoring ineffectual. Whether encryption makes VPN tunnel endpoints immune to fingerprinting, or yields the encrypted contents of the VPN tunnel entirely indistinguishable, is a topic that has received modest coverage in academic literature. This study addresses these question by targeting two tunnelling protocols: IPSec and SSL/TLS. A new fingerprinting methodology is presented, several fingerprinting discriminants are identified, and test results are set forth, showing that endpoint identities can be uncovered, and that some of the contents of encrypted VPN tunnels can in fact be discerned.Dissertation (MSc (Computer Science))--University of Pretoria, 2005.Computer Scienceunrestricte

    An Aesthetics of Hauntology

    Get PDF
    The text sets out to consider the aspects of the spectral, as proposed by Derrida in Spectres of Marx. As an alteric revenant refuting the historical/chronological determination of ratio and universality, it haunts the architectonics of the metaphysical edifice. This spectral 'operation' is also an activity of encryption which involves a discussion speculating on the virtual by proposing the transgressive rift as an introjective interruption that is realised through the abysmal (dis)order of fenestration. It uncovers a thematic of topological (dis)location via a series of 'meridial threads' which the dissertation seeks to explore through a scrutiny of aesthetics and specific creative activities. The first chapter explores this 'relation' with specific attention given to the alteric rift as an operation of differance as indicated by Derrida and seeks to critique this juxtaposition with particular reference and attention to Kant's aesthetics. Chapter two identifies Paul Celan's poem 'Todtnauberg' as a topos for a discussion on anticipation and silence in the complex historical relationship between the poet and the philosopher Martin Heidegger, as 'reported' in the poem. It identifies the topology of 'meridial haunting' at Heidegger's Black Forest mountain retreat. 'The Unheimlich Manoeuvre' (chapter three) deals with two key works by the architectural interventionist Gordon Matta-Clark, through a discussion on the uncanny (Unheimlich) and its relation to the homely (Heimlich), taking into account the encystic operation of mourning. The Final chapter continues this theme of the architecturally 'interruptive' by considering orientation with specific attention to the labyrinthine and the temporality of the crystal-image as cited by Deleuze in his writings on cinema and the spectral. It looks specifically at two films by Tarkovsky; Solaris and Stalker and Mark Z. Danelewski's novel House of Leaves (a complex fictitious account of a nonexistent documentary film which recounts the exploration of a labyrinth which appears in an ordinary suburban house)

    A Console GRID Leveraged Authentication and Key Agreement Mechanism for LTE/SAE

    Get PDF
    Growing popularity of multimedia applications, pervasive connectivity, higher bandwidth, and euphoric technology penetration among bulk of the human race that happens to be cellular technology users, has fueled the adaptation to long-term evolution (LTE)/system architecture evolution. The LTE fulfills the resource demands of the next generation applications for now. We identify security issues in authentication mechanism used in LTE that without countermeasures might give super user rights to unauthorized users. The LTE uses static LTE key to derive the entire key hierarchy, i.e., LTE follows Evolved Packet System–Authentication and Key Agreement based authentication, which discloses user identity, location, and other personally identifiable information. To counter this, we propose a public key cryptosystem named “International mobile subscriber identity Protected Console Grid based Authentication and Key Agreement (IPG-AKA) protocol” to address the vulnerabilities related to weak key management. From the data obtained from threat modeling and simulation results, we claim that the IPG-AKA scheme not only improves security of authentication procedures, but also shows improvements in authentication loads and reduction in key generation time. The empirical results and qualitative analysis presented in this paper prove that IPG-AKA improves security in authentication procedure and performance in the LTE
    • 

    corecore