40 research outputs found

    A Touch of Evil: High-Assurance Cryptographic Hardware from Untrusted Components

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    The semiconductor industry is fully globalized and integrated circuits (ICs) are commonly defined, designed and fabricated in different premises across the world. This reduces production costs, but also exposes ICs to supply chain attacks, where insiders introduce malicious circuitry into the final products. Additionally, despite extensive post-fabrication testing, it is not uncommon for ICs with subtle fabrication errors to make it into production systems. While many systems may be able to tolerate a few byzantine components, this is not the case for cryptographic hardware, storing and computing on confidential data. For this reason, many error and backdoor detection techniques have been proposed over the years. So far all attempts have been either quickly circumvented, or come with unrealistically high manufacturing costs and complexity. This paper proposes Myst, a practical high-assurance architecture, that uses commercial off-the-shelf (COTS) hardware, and provides strong security guarantees, even in the presence of multiple malicious or faulty components. The key idea is to combine protective-redundancy with modern threshold cryptographic techniques to build a system tolerant to hardware trojans and errors. To evaluate our design, we build a Hardware Security Module that provides the highest level of assurance possible with COTS components. Specifically, we employ more than a hundred COTS secure crypto-coprocessors, verified to FIPS140-2 Level 4 tamper-resistance standards, and use them to realize high-confidentiality random number generation, key derivation, public key decryption and signing. Our experiments show a reasonable computational overhead (less than 1% for both Decryption and Signing) and an exponential increase in backdoor-tolerance as more ICs are added

    E-mail encryption framework for Malaysian public sector

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    Securing confidential data shared through the electronic mail is depending on the current encryption method deployed by the E-mail service provider as well as the current procedures and regulation of the organization. Hence, the E-mail encryption framework is a fundamental factor in designing a secure E-mail service in the Malaysian Public Sector. Therefore, the purpose of this study is to develop the Email encryption framework for Malaysian Public Sector in order to secure the E-mail system. In this study, the qualitative study has been conducted in order to understand the criteria of the E-mail encryption framework for the Malaysian Public Sector. Thus, the descriptive design is conducted to discover the features E-mail encryption framework for Malaysian Public Sector from the E-mail administrator and related personnel. Therefore, in-depth interview with the semi-structured method of interview is used in this study. The E-mail encryption framework has been proposed which comprising of organizational, operational, technological, legal and ethical components. The proposed framework was evaluated to measure its effectiveness towards an existing e-mail system. Findings on the proposed e-mail encryption framework will benefit the Malaysian Public Sector in providing secure e-mail service thus deciding applicable security control. Finally, this study generally contributes to enhance the current secure e-mail system implementation in Malaysian public sector agencies

    Not-quite-so-broken TLS: Lessons in re-engineering a security protocol specification and implementation

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    A framework for comparing the security of voting schemes

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    We present a new framework to evaluate the security of voting schemes. We utilize the framework to compare a wide range of voting schemes, including practical schemes in realworld use and academic schemes with interesting theoretical properties. In the end we present our results in a neat comparison table. We strive to be unambiguous: we specify our threat model, assumptions and scope, we give definitions to the terms that we use, we explain every conclusion that we draw, and we make an effort to describe complex ideas in as simple terms as possible. We attempt to consolidate all important security properties from literature into a coherent framework. These properties are intended to curtail vote-buying and coercion, promote verifiability and dispute resolution, and prevent denial-of-service attacks. Our framework may be considered novel in that trust assumptions are an output of the framework, not an input. This means that our framework answers questions such as ”how many authorities have to collude in order to violate ballot secrecy in the Finnish paper voting scheme?

    Lawful Hacking: Using Existing Vulnerabilities for Wiretapping on the Internet

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    For years, legal wiretapping was straightforward: the officer doing the intercept connected a tape recorder or the like to a single pair of wires. By the 1990s, however, the changing structure of telecommunications—there was no longer just “Ma Bell” to talk to—and new technologies such as ISDN and cellular telephony made executing a wiretap more complicated for law enforcement. Simple technologies would no longer suffice. In response, Congress passed the Communications Assistance for Law Enforcement Act (CALEA) which mandated a standardized lawful intercept interface on all local phone switches. Since its passage, technology has continued to progress, and in the face of new forms of communication—Skype, voice chat during multiplayer online games, instant messaging, etc.—law enforcement is again experiencing problems. The FBI has called this “Going Dark”: their loss of access to suspects’ communication. According to news reports, law enforcement wants changes to the wiretap laws to require a CALEA-like interface in Internet software. CALEA, though, has its own issues: it is complex software specifically intended to create a security hole—eavesdropping capability—in the already-complex environment of a phone switch. It has unfortunately made wiretapping easier for everyone, not just law enforcement. Congress failed to heed experts’ warnings of the danger posed by this mandated vulnerability, and time has proven the experts right. The so-called “Athens Affair,” where someone used the built-in lawful intercept mechanism to listen to the cell phone calls of high Greek officials, including the Prime Minister, is but one example. In an earlier work, we showed why extending CALEA to the Internet would create very serious problems, including the security problems it has visited on the phone system. In this paper, we explore the viability and implications of an alternative method for addressing law enforcements need to access communications: legalized hacking of target devices through existing vulnerabilities in end-user software and platforms. The FBI already uses this approach on a small scale; we expect that its use will increase, especially as centralized wiretapping capabilities become less viable. Relying on vulnerabilities and hacking poses a large set of legal and policy questions, some practical and some normative. Among these are: (1) Will it create disincentives to patching? (2) Will there be a negative effect on innovation? (Lessons from the so-called “Crypto Wars” of the 1990s, and in particular the debate over export controls on cryptography, are instructive here.) (3) Will law enforcement’s participation in vulnerabilities purchasing skew the market? (4) Do local and even state law enforcement agencies have the technical sophistication to develop and use exploits? If not, how should this be handled? A larger FBI role? (5) Should law enforcement even be participating in a market where many of the sellers and other buyers are themselves criminals? (6) What happens if these tools are captured and repurposed by miscreants? (7) Should we sanction otherwise illegal network activity to aid law enforcement? (8) Is the probability of success from such an approach too low for it to be useful? As we will show, these issues are indeed challenging. We regard the issues raised by using vulnerabilities as, on balance, preferable to adding more complexity and insecurity to online systems

    Algorithm Substitution Attacks: Detecting ASAs Using State Reset and Making ASAs Asymmetric

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    The field of cryptography has made incredible progress in the last several decades. With the formalization of security goals and the methods of provable security, we have achieved many privacy and integrity guarantees in a great variety of situations. However, all guarantees are limited by their assumptions on the model's adversaries. Edward Snowden's revelations of the participation of the National Security Agency (NSA) in the subversion of standardized cryptography have shown that powerful adversaries will not always act in the way that common cryptographic models assume. As such, it is important to continue to expand the capabilities of the adversaries in our models to match the capabilities and intentions of real world adversaries, and to examine the consequences on the security of our cryptography. In this thesis, we study Algorithm Substitution Attacks (ASAs), which are one way to model this increase in adversary capability. In an ASA, an algorithm in a cryptographic scheme Λ is substituted for a subverted version. The goal of the adversary is to recover a secret that will allow them to compromise the security of Λ, while requiring that the attack is undetectable to the users of the scheme. This model was first formally described by Bellare, Paterson, and Rogaway (Crypto 2014), and allows for the possibility of a wide variety of cryptographic subversion techniques. Since their paper, many successful ASAs on various cryptographic primitives and potential countermeasures have been demonstrated. We will address several shortcomings in the existing literature. First, we formalize and study the use of state resets to detect ASAs. While state resets have been considered as a possible detection method since the first papers on ASAs, future works have only informally reasoned about the effect of state resets on ASAs. We show that many published ASAs that use state are detectable with simple practical methods relying on state resets. Second, we add to the study of asymmetric ASAs, where the ability to recover secrets is restricted to the attacker who implemented the ASA. We describe two asymmetric ASAs on symmetric encryption based on modifications to previous ASAs. We also generalize this result, allowing for any symmetric ASA (on any cryptographic scheme) satisfying certain properties to be transformed into an asymmetric ASA. This work demonstrates the broad application of the techniques first introduced by Bellare, Paterson, and Rogaway (Crypto 2014) and Bellare, Jaeger, and Kane (CCS 2015) and reinforces the need for precise definitions surrounding detectability of stateful ASAs

    Nation-State Attackers and their Effects on Computer Security

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    Nation-state intelligence agencies have long attempted to operate in secret, but recent revelations have drawn the attention of security researchers as well as the general public to their operations. The scale, aggressiveness, and untargeted nature of many of these now public operations were not only alarming, but also baffling as many were thought impossible or at best infeasible at scale. The security community has since made many efforts to protect end-users by identifying, analyzing, and mitigating these now known operations. While much-needed, the security community's response has largely been reactionary to the oracled existence of vulnerabilities and the disclosure of specific operations. Nation-State Attackers, however, are dynamic, forward-thinking, and surprisingly agile adversaries who do not rest on their laurels and are continually advancing their efforts to obtain information. Without the ability to conceptualize their actions, understand their perspective, or account for their presence, the security community's advances will become antiquated and unable to defend against the progress of Nation-State Attackers. In this work, we present and discuss a model of Nation-State Attackers that can be used to represent their attributes, behavior patterns, and world view. We use this representation of Nation-State Attackers to show that real-world threat models do not account for such highly privileged attackers, to identify and support technical explanations of known but ambiguous operations, and to identify and analyze vulnerabilities in current systems that are favorable to Nation-State Attackers.PHDComputer Science & EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttps://deepblue.lib.umich.edu/bitstream/2027.42/143907/1/aaspring_1.pd
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