1,613 research outputs found
CALIPER: Continuous Authentication Layered with Integrated PKI Encoding Recognition
Architectures relying on continuous authentication require a secure way to
challenge the user's identity without trusting that the Continuous
Authentication Subsystem (CAS) has not been compromised, i.e., that the
response to the layer which manages service/application access is not fake. In
this paper, we introduce the CALIPER protocol, in which a separate Continuous
Access Verification Entity (CAVE) directly challenges the user's identity in a
continuous authentication regime. Instead of simply returning authentication
probabilities or confidence scores, CALIPER's CAS uses live hard and soft
biometric samples from the user to extract a cryptographic private key embedded
in a challenge posed by the CAVE. The CAS then uses this key to sign a response
to the CAVE. CALIPER supports multiple modalities, key lengths, and security
levels and can be applied in two scenarios: One where the CAS must authenticate
its user to a CAVE running on a remote server (device-server) for access to
remote application data, and another where the CAS must authenticate its user
to a locally running trusted computing module (TCM) for access to local
application data (device-TCM). We further demonstrate that CALIPER can leverage
device hardware resources to enable privacy and security even when the device's
kernel is compromised, and we show how this authentication protocol can even be
expanded to obfuscate direct kernel object manipulation (DKOM) malwares.Comment: Accepted to CVPR 2016 Biometrics Worksho
A New Cryptosystem Based On Hidden Order Groups
Let be a cyclic multiplicative group of order . It is known that the
Diffie-Hellman problem is random self-reducible in with respect to a
fixed generator if is known. That is, given and
having oracle access to a `Diffie-Hellman Problem' solver with fixed generator
, it is possible to compute in polynomial time (see
theorem 3.2). On the other hand, it is not known if such a reduction exists
when is unknown (see conjuncture 3.1). We exploit this ``gap'' to
construct a cryptosystem based on hidden order groups and present a practical
implementation of a novel cryptographic primitive called an \emph{Oracle Strong
Associative One-Way Function} (O-SAOWF). O-SAOWFs have applications in
multiparty protocols. We demonstrate this by presenting a key agreement
protocol for dynamic ad-hoc groups.Comment: removed examples for multiparty key agreement and join protocols,
since they are redundan
Quantum Cryptography Beyond Quantum Key Distribution
Quantum cryptography is the art and science of exploiting quantum mechanical
effects in order to perform cryptographic tasks. While the most well-known
example of this discipline is quantum key distribution (QKD), there exist many
other applications such as quantum money, randomness generation, secure two-
and multi-party computation and delegated quantum computation. Quantum
cryptography also studies the limitations and challenges resulting from quantum
adversaries---including the impossibility of quantum bit commitment, the
difficulty of quantum rewinding and the definition of quantum security models
for classical primitives. In this review article, aimed primarily at
cryptographers unfamiliar with the quantum world, we survey the area of
theoretical quantum cryptography, with an emphasis on the constructions and
limitations beyond the realm of QKD.Comment: 45 pages, over 245 reference
Efficient cryptographic primitives: Secure comparison, binary decomposition and proxy re-encryption
”Data outsourcing becomes an essential paradigm for an organization to reduce operation costs on supporting and managing its IT infrastructure. When sensitive data are outsourced to a remote server, the data generally need to be encrypted before outsourcing. To preserve the confidentiality of the data, any computations performed by the server should only be on the encrypted data. In other words, the encrypted data should not be decrypted during any stage of the computation. This kind of task is commonly termed as query processing over encrypted data (QPED).
One natural solution to solve the QPED problem is to utilize fully homomorphic encryption. However, fully homomorphic encryption is yet to be practical. The second solution is to adopt multi-server setting. However, the existing work is not efficient. Their implementations adopt costly primitives, such as secure comparison, binary decomposition among others, which reduce the efficiency of the whole protocols. Therefore, the improvement of these primitives results in high efficiency of the protocols. To have a well-defined scope, the following types of computations are considered: secure comparison (CMP), secure binary decomposition (SBD) and proxy re-encryption (PRE). We adopt the secret sharing scheme and paillier public key encryption as building blocks, and all computations can be done on the encrypted data by utilizing multiple servers. We analyze the security and the complexity of our proposed protocols, and their efficiencies are evaluated by comparing with the existing solutions.”--Abstract, page iii
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