A verifiable random function with short proofs and keys
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The document describes a construction of a verifiable random function (VRF) that improves upon previous work. It directly constructs a VRF without using Goldreich-Levin hardcore bits, allows inputs of arbitrary size without encoding, and has proofs and keys consisting of a constant number of group elements. The security of the VRF relies on complexity assumptions in bilinear groups and it finds applications like non-interactive lotteries and compact e-cash schemes.
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Malware can spread through media files like videos, music and images. Attackers use social engineering tricks to get users to download malware disguised as codecs or licenses. Various exploits in media file formats and plugins allow inserting malicious scripts. Users should disable risky player settings like URLANDEXIT, check files with scanning tools, and avoid untrusted sources.
Privacy and E-Commerce
The document summarizes key points about privacy in e-commerce from a presentation given by Aleksandr Yampolskiy, head of security and compliance at Gilt Groupe. It discusses how much personal information is readily available online, the difference between privacy and security, why people disclose personal information, challenges with privacy in e-commerce, and solutions companies can implement like having a clear privacy policy and controlling access to customer data.
Eight simple rules to writing secure PHP programs
This document provides eight rules for writing secure PHP programs:
1. Use proper cryptography and do not invent your own algorithms.
2. Validate all input from external sources before using.
3. Sanitize data sent to databases or other systems to prevent injection attacks.
4. Avoid leaking sensitive information through error messages or other means.
5. Properly manage user sessions to prevent hijacking and ensure users remain authenticated.
6. Enforce authentication and authorization separately using least privilege.
7. Use SSL/TLS to encrypt all authenticated or sensitive communications.
8. Keep security straightforward and avoid relying on obscurity.
Social media security challenges
Social media presents both opportunities and risks for individuals and organizations. It allows for quicker outreach to customers, improved branding and recruitment but also expands the potential attack surface. The document recommends that organizations address social media security by developing clear policies on allowed and prohibited uses, taking a permissive approach while monitoring usage, applying general web security best practices, and reminding employees to use separate personal and work passwords.
Social Engineering and What to do About it
The document discusses social engineering techniques and defenses against them. It defines social engineering as manipulating people into revealing sensitive information through deception. Various social engineering methods are described, including in-person manipulation, phone calls, emails, and fake websites. It explains how social engineers use techniques like impersonation, building rapport, and exploiting human tendencies to make targets feel obligated or conform to social pressures. The document recommends defenses like user education, identity verification protocols for customer support, and having an incident response plan to address social engineering attacks. The goal is to help organizations strengthen their "human firewall" against this threat.
OWASP Much ado about randomness
This document discusses randomness and random number generation. It notes that cryptography relies on random numbers, but that generating truly random numbers is difficult. While theory assumes a perfect random source, in practice pseudorandom number generators are used. Several examples are given of systems that used weak random number generation that led to security issues. Lessons discussed include the importance of unpredictable seeds for pseudorandom number generators and using cryptographically secure functions. The document contrasts truly random and pseudorandom number generation, and provides tips for analyzing randomness in programs and web applications.
Malware goes to the movies
This document summarizes trends in media malware and discusses case studies of attacks. It notes that media files like videos, music and images are common infection vectors because media is widely consumed online. Fake YouTube videos, malicious torrents, and exploits of media file formats like ASF are described as major attack methods. The document recommends disabling risky media player functions, using tools to detect malicious scripts in files, and verifying the reputation of URLs found in media before interacting with them. Detection of attacks and education of users on safe media practices are emphasized.
Inoculation strategies for victims of viruses
This document discusses strategies for containing computer viruses in a network. It presents a game theoretic model where nodes choose whether to install antivirus software. Nash equilibria are characterized but can be inefficient. Computing the optimal strategy that minimizes total infection risk is NP-hard. Approximating this solution can be reduced to the sum-of-squares partition problem, allowing for a near-optimal deployment. Open problems consider extensions like taxation mechanisms and strategic behavior.
Number theory lecture (part 1)
Cryptography and data security involves number theory concepts like groups, rings, fields, and modular arithmetic. Some key ideas discussed include:
1) The integers under addition form a cyclic group, and the theorem that for any finite group G and element a in G, a raised to the order of G is the identity element.
2) Modular arithmetic defines equivalence classes for integers modulo n, and the set of residues Zn forms an abelian group under addition.
3) The multiplicative integers modulo n, Zn*, form a group whose size is given by Euler's totient function φ(n). For prime p, φ(p) = p - 1.
Number theory lecture (part 2)
Cryptography and Data Security often relies on number theory concepts. This document reviews several key number theory topics used in cryptography, including: 1) integers modulo n and Euler's totient function; 2) Euler's theorem and Fermat's theorem; 3) the greatest common divisor and Euclid's algorithm; and 4) polynomials and finite fields. Finite fields play an important role in cryptography by allowing the representation of data as field elements.
Much ado about randomness. What is really a random number?
The document discusses weaknesses in random number generation and pseudorandom number generation (PRNG) that can be exploited by attackers. It provides examples of programs that used weak PRNGs, allowing session IDs and keys to be guessed. Lessons learned are that numbers used to derive keys and IDs must be truly random and unpredictable, and PRNGs must be cryptographically secure. Two types of randomness are defined: true randomness from unpredictable sources, and pseudorandomness from cryptographically secure PRNGs seeded with true randomness.
Secure information aggregation in sensor networks
The document summarizes the paper "Secure Information Aggregation in Sensor Networks" which proposes a framework called aggregate-commit-prove for securely computing aggregation functions like median, min/max, counting distinct elements in sensor networks even if sensors or aggregators are compromised. It describes the sensor network model, attack model, and gives concrete sublinear protocols for computing specific aggregation functions that allow the base station to detect incorrect results with high probability.
Towards a theory of data entangelement
The document proposes a model for entangling users' data to protect remotely stored data from server corruption. It defines six adversary classes based on the recovery algorithm (standard, public, private) and corruption method (destructive, arbitrary). It shows all-or-nothing integrity is possible in the standard-recovery model by using message authentication codes, but not in public/private models as adversaries can modify the recovery algorithm. Symmetric recovery is possible in the public model if encoding is symmetric. All-or-nothing integrity is achievable against destructive adversaries by interpolating a polynomial of the data.
Price of anarchy is independent of network topology
1. The document discusses a model for analyzing traffic flows in networks where individual agents route traffic selfishly according to latency costs.
2. It shows that for linear latency functions, the ratio between the cost of the Nash equilibrium flow and the optimal flow (the price of anarchy) is 4/3, independent of network topology.
3. For general latency functions, the price of anarchy may be larger and depends on properties of the latency function class, but is still independent of network topology.
Business Case Studies
The document outlines 11 case scenarios that an expert may encounter and provides questions to consider for each scenario. The scenarios include deciding whether to enter a new market, evaluating mergers and acquisitions, reducing costs, increasing sales and profits, executing a turnaround, responding to competitors, developing new products, determining pricing strategies, pursuing growth strategies, starting a new business, and using frameworks like the five C's and four P's for analysis.
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