4,677 research outputs found
Keeping Authorities "Honest or Bust" with Decentralized Witness Cosigning
The secret keys of critical network authorities - such as time, name,
certificate, and software update services - represent high-value targets for
hackers, criminals, and spy agencies wishing to use these keys secretly to
compromise other hosts. To protect authorities and their clients proactively
from undetected exploits and misuse, we introduce CoSi, a scalable witness
cosigning protocol ensuring that every authoritative statement is validated and
publicly logged by a diverse group of witnesses before any client will accept
it. A statement S collectively signed by W witnesses assures clients that S has
been seen, and not immediately found erroneous, by those W observers. Even if S
is compromised in a fashion not readily detectable by the witnesses, CoSi still
guarantees S's exposure to public scrutiny, forcing secrecy-minded attackers to
risk that the compromise will soon be detected by one of the W witnesses.
Because clients can verify collective signatures efficiently without
communication, CoSi protects clients' privacy, and offers the first
transparency mechanism effective against persistent man-in-the-middle attackers
who control a victim's Internet access, the authority's secret key, and several
witnesses' secret keys. CoSi builds on existing cryptographic multisignature
methods, scaling them to support thousands of witnesses via signature
aggregation over efficient communication trees. A working prototype
demonstrates CoSi in the context of timestamping and logging authorities,
enabling groups of over 8,000 distributed witnesses to cosign authoritative
statements in under two seconds.Comment: 20 pages, 7 figure
A Touch of Evil: High-Assurance Cryptographic Hardware from Untrusted Components
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
HORNET: High-speed Onion Routing at the Network Layer
We present HORNET, a system that enables high-speed end-to-end anonymous
channels by leveraging next generation network architectures. HORNET is
designed as a low-latency onion routing system that operates at the network
layer thus enabling a wide range of applications. Our system uses only
symmetric cryptography for data forwarding yet requires no per-flow state on
intermediate nodes. This design enables HORNET nodes to process anonymous
traffic at over 93 Gb/s. HORNET can also scale as required, adding minimal
processing overhead per additional anonymous channel. We discuss design and
implementation details, as well as a performance and security evaluation.Comment: 14 pages, 5 figure
Communication Efficient Checking of Big Data Operations
We propose fast probabilistic algorithms with low (i.e., sublinear in the
input size) communication volume to check the correctness of operations in Big
Data processing frameworks and distributed databases. Our checkers cover many
of the commonly used operations, including sum, average, median, and minimum
aggregation, as well as sorting, union, merge, and zip. An experimental
evaluation of our implementation in Thrill (Bingmann et al., 2016) confirms the
low overhead and high failure detection rate predicted by theoretical analysis
Proof of Latency Using a Verifiable Delay Function
In this thesis I present an interactive public-coin protocol called Proof of Latency (PoL) that aims to improve connections in peer-to-peer networks by measuring latencies with logical clocks built from verifiable delay functions (VDF). PoL is a tuple of three algorithms, Setup(e, λ), VCOpen(c, e), and Measure(g, T, l_p, l_v). Setup creates a vector commitment (VC), from which a vector commitment opening corresponding to a collaborator's public key is taken in VCOpen, which then gets used to create a common reference string used in Measure. If no collusion gets detected by neither party, a signed proof is ready for advertising. PoL is agnostic in terms of the individual implementations of the VC or VDF used. This said, I present a proof of concept in the form of a state machine implemented in Rust that uses RSA-2048, Catalano-Fiore vector commitments and Wesolowski's VDF to demonstrate PoL. As VDFs themselves have been shown to be useful in timestamping, they seem to work as a measurement of time in this context as well, albeit requiring a public performance metric for each peer to compare to during the measurement. I have imagined many use cases for PoL, like proving a geographical location, working as a benchmark query, or using the proofs to calculate VDFs with the latencies between peers themselves. As it stands, PoL works as a distance bounding protocol between two participants, considering their computing performance is relatively similar. More work is needed to verify the soundness of PoL as a publicly verifiable proof that a third party can believe in.Tässä tutkielmassa esitän interaktiivisen protokollan nimeltä Proof of latency (PoL), joka pyrkii parantamaan yhteyksiä vertaisverkoissa mittaamalla viivettä todennettavasta viivefunktiosta rakennetulla loogisella kellolla. Proof of latency koostuu kolmesta algoritmista, Setup(e, λ), VCOpen(c, e) ja Measure(g, T, l_p, l_v). Setup luo vektorisitoumuksen, josta luodaan avaus algoritmissa VCOpen avaamalla vektorisitoumus indeksistä, joka kuvautuu toisen mittaavan osapuolen julkiseen avaimeen. Tätä avausta käytetään luomaan yleinen viitemerkkijono, jota käytetään algoritmissa Measure alkupisteenä molempien osapuolien todennettavissa viivefunktioissa mittaamaan viivettä. Jos kumpikin osapuoli ei huomaa virheitä mittauksessa, on heidän allekirjoittama todistus valmis mainostettavaksi vertaisverkossa. PoL ei ota kantaa sen käyttämien kryptografisten funktioiden implementaatioon. Tästä huolimatta olen ohjelmoinut protokollasta prototyypin Rust-ohjelmointikielellä käyttäen RSA-2048:tta, Catalano-Fiore--vektorisitoumuksia ja Wesolowskin todennettavaa viivefunktiota protokollan esittelyyn. Todistettavat viivefunktiot ovat osoittaneet hyödyllisiksi aikaleimauksessa, mikä näyttäisi osoittavan niiden soveltumisen myös ajan mittaamiseen tässä konteksissa, huolimatta siitä että jokaisen osapuolen tulee ilmoittaa julkisesti teholukema, joka kuvaa niiden tehokkuutta viivefunktioiden laskemisessa. Toinen osapuoli käyttää tätä lukemaa arvioimaan valehteliko toinen viivemittauksessa. Olen kuvitellut monta käyttökohdetta PoL:lle, kuten maantieteellisen sijainnin todistaminen, suorituskykytestaus, tai itse viivetodistuksien käyttäminen uusien viivetodistusten laskemisessa vertaisverkon osallistujien välillä. Tällä hetkellä PoL toimii etäisyydenmittausprotokollana kahden osallistujan välillä, jos niiden suorituskyvyt ovat tarpeeksi lähellä toisiaan. Protokolla tarvitsee lisätutkimusta sen suhteen, voiko se toimia uskottavana todistuksena kolmansille osapuolille kahden vertaisverkon osallistujan välisestä viiveestä
A Survey on Wireless Security: Technical Challenges, Recent Advances and Future Trends
This paper examines the security vulnerabilities and threats imposed by the
inherent open nature of wireless communications and to devise efficient defense
mechanisms for improving the wireless network security. We first summarize the
security requirements of wireless networks, including their authenticity,
confidentiality, integrity and availability issues. Next, a comprehensive
overview of security attacks encountered in wireless networks is presented in
view of the network protocol architecture, where the potential security threats
are discussed at each protocol layer. We also provide a survey of the existing
security protocols and algorithms that are adopted in the existing wireless
network standards, such as the Bluetooth, Wi-Fi, WiMAX, and the long-term
evolution (LTE) systems. Then, we discuss the state-of-the-art in
physical-layer security, which is an emerging technique of securing the open
communications environment against eavesdropping attacks at the physical layer.
We also introduce the family of various jamming attacks and their
counter-measures, including the constant jammer, intermittent jammer, reactive
jammer, adaptive jammer and intelligent jammer. Additionally, we discuss the
integration of physical-layer security into existing authentication and
cryptography mechanisms for further securing wireless networks. Finally, some
technical challenges which remain unresolved at the time of writing are
summarized and the future trends in wireless security are discussed.Comment: 36 pages. Accepted to Appear in Proceedings of the IEEE, 201
Joint secure communication and sensing in 6G networks
Joint communication and sensing is expected to be one of the features
introduced by the sixth-generation (6G) wireless systems. This will enable a
huge variety of new applications, hence, it is important to find suitable
approaches to secure the exchanged information. Conventional security
mechanisms may not be able to meet the stringent delay, power, and complexity
requirements which opens the challenge of finding new lightweight security
solutions. A promising approach coming from the physical layer is the secret
key generation (SKG) from channel fading. While SKG has been investigated for
several decades, practical implementations of its full protocol are still
scarce. The aim of this chapter is to evaluate the SKG rates in real-life
setups under a set of different scenarios. We consider a typical radar waveform
and present a full implementation of the SKG protocol. Each step is evaluated
to demonstrate that generating keys from the physical layer can be a viable
solution for future networks. However, we show that there is not a single
solution that can be generalized for all cases, instead, parameters should be
chosen according to the context
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