9,833 research outputs found
Breaking Web Applications Built On Top of Encrypted Data
We develop a systematic approach for analyzing client-server
applications that aim to hide sensitive user data from untrusted servers. We then apply it to Mylar, a framework that uses multi-key searchable encryption (MKSE) to build Web applications on top of encrypted data. We demonstrate that (1) the Popa-Zeldovich model for MKSE does not imply security against either passive or active attacks; (2) Mylar-based Web applications reveal users’ data and queries to passive and active adversarial servers; and (3) Mylar is generically insecure against active attacks due to system design flaws. Our results show that the problem of securing client-server applications against actively malicious servers is challenging and still unsolved. We conclude with general lessons for the designers of systems that rely on property-preserving or searchable encryption to protect data from untrusted servers
Web API Fragility: How Robust is Your Web API Client
Web APIs provide a systematic and extensible approach for
application-to-application interaction. A large number of mobile applications
makes use of web APIs to integrate services into apps. Each Web API's evolution
pace is determined by their respective developer and mobile application
developers are forced to accompany the API providers in their software
evolution tasks. In this paper we investigate whether mobile application
developers understand and how they deal with the added distress of web APIs
evolving. In particular, we studied how robust 48 high profile mobile
applications are when dealing with mutated web API responses. Additionally, we
interviewed three mobile application developers to better understand their
choices and trade-offs regarding web API integration.Comment: Technical repor
ESTABLISHED WAYS TO ATTACK EVEN THE BEST ENCRYPTION ALGORITHM
Which solution is the best – public key or private key encryption? This question cannot have a very rigorous, logical and definitive answer, so that the matter be forever settled :). The question supposes that the two methods could be compared on completely the same indicators – well, from my point of view, the comparison is not very relevant. Encryption specialists have demonstrated that the sizes of public key encrypted messages are much bigger than the encrypted message using private key algorithms. From this point of view, we can say that private key algorithms are more efficient than their newer counterparts. Looking at the issue through the eyeglass of the security level, the public key encryption have a great advantage of the private key variants, their level of protection, in the most pessimistic scenarios, being at least 35 time higher. As a general rule, each type of algorithm has managed to find its own market niche where could be applicable as a best solution and be more efficient than the other encryption model.Encryption, decryption, key, cryptanalysis, brute-force, linear, differential, algebra
Compromising Tor Anonymity Exploiting P2P Information Leakage
Privacy of users in P2P networks goes far beyond their current usage and is a
fundamental requirement to the adoption of P2P protocols for legal usage. In a
climate of cold war between these users and anti-piracy groups, more and more
users are moving to anonymizing networks in an attempt to hide their identity.
However, when not designed to protect users information, a P2P protocol would
leak information that may compromise the identity of its users. In this paper,
we first present three attacks targeting BitTorrent users on top of Tor that
reveal their real IP addresses. In a second step, we analyze the Tor usage by
BitTorrent users and compare it to its usage outside of Tor. Finally, we depict
the risks induced by this de-anonymization and show that users' privacy
violation goes beyond BitTorrent traffic and contaminates other protocols such
as HTTP
Introducing Accountability to Anonymity Networks
Many anonymous communication (AC) networks rely on routing traffic through
proxy nodes to obfuscate the originator of the traffic. Without an
accountability mechanism, exit proxy nodes risk sanctions by law enforcement if
users commit illegal actions through the AC network. We present BackRef, a
generic mechanism for AC networks that provides practical repudiation for the
proxy nodes by tracing back the selected outbound traffic to the predecessor
node (but not in the forward direction) through a cryptographically verifiable
chain. It also provides an option for full (or partial) traceability back to
the entry node or even to the corresponding user when all intermediate nodes
are cooperating. Moreover, to maintain a good balance between anonymity and
accountability, the protocol incorporates whitelist directories at exit proxy
nodes. BackRef offers improved deployability over the related work, and
introduces a novel concept of pseudonymous signatures that may be of
independent interest.
We exemplify the utility of BackRef by integrating it into the onion routing
(OR) protocol, and examine its deployability by considering several
system-level aspects. We also present the security definitions for the BackRef
system (namely, anonymity, backward traceability, no forward traceability, and
no false accusation) and conduct a formal security analysis of the OR protocol
with BackRef using ProVerif, an automated cryptographic protocol verifier,
establishing the aforementioned security properties against a strong
adversarial model
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