35,120 research outputs found
Conference Key Agreement and Quantum Sharing of Classical Secrets with Noisy GHZ States
We propose a wide class of distillation schemes for multi-partite entangled
states that are CSS-states. Our proposal provides not only superior efficiency,
but also new insights on the connection between CSS-states and bipartite graph
states. We then consider the applications of our distillation schemes for two
cryptographic tasks--namely, (a) conference key agreement and (b) quantum
sharing of classical secrets. In particular, we construct
``prepare-and-measure'' protocols. Also we study the yield of those protocols
and the threshold value of the fidelity above which the protocols can function
securely. Surprisingly, our protocols will function securely even when the
initial state does not violate the standard Bell-inequalities for GHZ states.
Experimental realization involving only bi-partite entanglement is also
suggested.Comment: 5 pages, to appear in Proc. 2005 IEEE International Symposium on
Information Theory (ISIT 2005, Adelaide, Australia
Keys in the Clouds: Auditable Multi-device Access to Cryptographic Credentials
Personal cryptographic keys are the foundation of many secure services, but
storing these keys securely is a challenge, especially if they are used from
multiple devices. Storing keys in a centralized location, like an
Internet-accessible server, raises serious security concerns (e.g. server
compromise). Hardware-based Trusted Execution Environments (TEEs) are a
well-known solution for protecting sensitive data in untrusted environments,
and are now becoming available on commodity server platforms.
Although the idea of protecting keys using a server-side TEE is
straight-forward, in this paper we validate this approach and show that it
enables new desirable functionality. We describe the design, implementation,
and evaluation of a TEE-based Cloud Key Store (CKS), an online service for
securely generating, storing, and using personal cryptographic keys. Using
remote attestation, users receive strong assurance about the behaviour of the
CKS, and can authenticate themselves using passwords while avoiding typical
risks of password-based authentication like password theft or phishing. In
addition, this design allows users to i) define policy-based access controls
for keys; ii) delegate keys to other CKS users for a specified time and/or a
limited number of uses; and iii) audit all key usages via a secure audit log.
We have implemented a proof of concept CKS using Intel SGX and integrated this
into GnuPG on Linux and OpenKeychain on Android. Our CKS implementation
performs approximately 6,000 signature operations per second on a single
desktop PC. The latency is in the same order of magnitude as using
locally-stored keys, and 20x faster than smart cards.Comment: Extended version of a paper to appear in the 3rd Workshop on
Security, Privacy, and Identity Management in the Cloud (SECPID) 201
A comprehensive meta-analysis of cryptographic security mechanisms for cloud computing
The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.The concept of cloud computing offers measurable computational or information resources as a service over the Internet. The major motivation behind the cloud setup is economic benefits, because it assures the reduction in expenditure for operational and infrastructural purposes. To transform it into a reality there are some impediments and hurdles which are required to be tackled, most profound of which are security, privacy and reliability issues. As the user data is revealed to the cloud, it departs the protection-sphere of the data owner. However, this brings partly new security and privacy concerns. This work focuses on these issues related to various cloud services and deployment models by spotlighting their major challenges. While the classical cryptography is an ancient discipline, modern cryptography, which has been mostly developed in the last few decades, is the subject of study which needs to be implemented so as to ensure strong security and privacy mechanisms in today’s real-world scenarios. The technological solutions, short and long term research goals of the cloud security will be described and addressed using various classical cryptographic mechanisms as well as modern ones. This work explores the new directions in cloud computing security, while highlighting the correct selection of these fundamental technologies from cryptographic point of view
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