388 research outputs found
KeyForge: Mitigating Email Breaches with Forward-Forgeable Signatures
Email breaches are commonplace, and they expose a wealth of personal,
business, and political data that may have devastating consequences. The
current email system allows any attacker who gains access to your email to
prove the authenticity of the stolen messages to third parties -- a property
arising from a necessary anti-spam / anti-spoofing protocol called DKIM. This
exacerbates the problem of email breaches by greatly increasing the potential
for attackers to damage the users' reputation, blackmail them, or sell the
stolen information to third parties.
In this paper, we introduce "non-attributable email", which guarantees that a
wide class of adversaries are unable to convince any third party of the
authenticity of stolen emails. We formally define non-attributability, and
present two practical system proposals -- KeyForge and TimeForge -- that
provably achieve non-attributability while maintaining the important protection
against spam and spoofing that is currently provided by DKIM. Moreover, we
implement KeyForge and demonstrate that that scheme is practical, achieving
competitive verification and signing speed while also requiring 42% less
bandwidth per email than RSA2048
Deniable encryption, authentication, and key exchange
We present some foundational ideas related to deniable encryption, message authentication, and key exchange in classical cryptography. We give detailed proofs of results that were previously only sketched in the literature. In some cases, we reach the same conclusions as in previous papers; in other cases, the focus on rigorous proofs leads us to different formulations of the results
Design of a secure unified e-payment system in Nigeria: A case study
The automatic teller machine (ATM) is the most widely used e-Payment instrument in Nigeria. It is responsible for about 89% (in volume) of all e-Payment instruments since 2006 to 2008. Some customers have at least two ATM cards depending on the number of accounts operated by them and
they represent the active users of the ATM cards. Furthermore, identity theft has been identified as one
of the most prominent problems hindering the wider adoption of e-Business, particularly e-Banking, hence the need for a more secure platform of operation. Therefore, in this paper we propose a unified (single) smart card-based ATM card with biometric-based cash dispenser for all banking transactions.
This is to reduce the number of ATM cards carried by an individual and the biometric facility is to introduce another level of security in addition to the PIN which is currently being used. A set of questionnaire was designed to evaluate the acceptability of this concept among users and the architecture of the proposed system is presented
Deniable Key Establishment Resistance against eKCI Attacks
In extended Key Compromise Impersonation (eKCI) attack against authenticated key establishment (AKE) protocols the adversary impersonates one party, having the long term key and the ephemeral key of the other peer party. Such an attack can be mounted against variety of AKE protocols, including 3-pass HMQV. An intuitive countermeasure, based on BLS (BonehâLynnâShacham) signatures, for strengthening HMQV was proposed in literature. The original HMQV protocol fulfills the deniability property: a party can deny its participation in the protocol execution, as the peer party can create a fake protocol transcript indistinguishable from the real one. Unfortunately, the modified BLS based version of HMQV is not deniable. In this paper we propose a method for converting HMQV (and similar AKE protocols) into a protocol resistant to eKCI attacks but without losing the original deniability property. For that purpose, instead of the undeniable BLS, we use a modification of Schnorr authentication protocol, which is deniable and immune to ephemeral key leakages
- âŠ