Despite a great deal of work to improve the TLS PKI, CA misbehavior continues to occur, resulting in unauthorized certificates that can be used to mount man-in-the-middle attacks against HTTPS sites. CAs lack the incentives to invest in higher security, and the manual effort required to report a rogue certificate deters many from contributing to the security of the TLS PKI. In this paper, we present IKP, a platform that automates responses to unauthorized certificates and provides incentives for CAs to behave correctly and for others to report potentially unauthorized certificates. Domains in IKP specify criteria for their certificates, and CAs specify reactions such as financial penalties that execute in case of unauthorized certificate issuance. By leveraging smart contracts and blockchain-based consensus, we can decentralize IKP while still providing automated incentives. We describe a theoretical model for payment flows and implement IKP in Ethereum to show that decentralizing and automating PKIs with financial incentives is both economically sound and technically viable.

/pdf/ikp-turning-a-pki-around-with-decentralized-automated-4gzgan5yjr.pdf

IKP: Turning a PKI Around with Decentralized Automated Incentives

We present Catena, an efficiently-verifiable Bitcoinwitnessing scheme. Catena enables any number of thin clients, such as mobile phones, to efficiently agree on a log of application-specific statements managed by an adversarial server. Catenaimplements a log as an OP_RETURN transaction chain andprevents forks in the log by leveraging Bitcoin's security againstdouble spends. Specifically, if a log server wants to equivocate ithas to double spend a Bitcoin transaction output. Thus, Catenalogs are as hard to fork as the Bitcoin blockchain: an adversarywithout a large fraction of the network's computational powercannot fork Bitcoin and thus cannot fork a Catena log either. However, different from previous Bitcoin-based work, Catenadecreases the bandwidth requirements of log auditors from 90GB to only tens of megabytes. More precisely, our clients onlyneed to download all Bitcoin block headers (currently less than35 MB) and a small, 600-byte proof for each statement in a block. We implement Catena in Java using the bitcoinj library and use itto extend CONIKS, a recent key transparency scheme, to witnessits public-key directory in the Bitcoin blockchain where it can beefficiently verified by auditors. We show that Catena can securemany systems today, such as public-key directories, Tor directoryservers and software transparency schemes.

https://www.computer.org/csdl/pds/api/csdl/proceedings/download-article/1ap5pmaUkIE/pdf

Catena: Efficient Non-equivocation via Bitcoin

Central banks around the world are exploring and in some cases even piloting Central Bank Digital Currencies (CBDCs). CBDCs promise to realize a broad range of new capabilities, including direct government disbursements to citizens, frictionless consumer payment and money-transfer systems, and a range of new financial instruments and monetary policy levers. CBDCs also give rise, however, to a host of challenging technical goals and design questions that are qualitatively and quantitatively different from those in existing government and consumer payment systems. A well-functioning CBDC will require an extremely resilient, secure, and performant new infrastructure, with the ability to onboard, authenticate, and support users on massive scale. It will necessitate an architecture simple enough to support modular design and rigorous security analysis, but flexible enough to accommodate current and future functional requirements and use cases. A CBDC will also in some way need to address an innate tension between privacy and transparency, protecting user data from abuse while selectively permitting data mining for end-user services, policymakers, and law enforcement investigations and interventions. In this paper, we enumerate the fundamental technical design challenges facing CBDC designers, with a particular focus on performance, privacy, and security. Through a survey of relevant academic and industry research and deployed systems, we discuss the state of the art in technologies that can address the challenges involved in successful CBDC deployment. We also present a vision of the rich range of functionalities and use cases that a well-designed CBDC platform could ultimately offer users.

/pdf/design-choices-for-central-bank-digital-currency-policy-and-45k78rpvog.pdf

Design Choices for Central Bank Digital Currency: Policy and Technical Considerations

The emergence of Internet protocol suites and packet-switching technologies tends to the considerations of security, privacy, scalability, and reliability in layered Internet service architectures. The existing service systems allow us to access big data, but few studies focus on the fundamental security and stability in these systems, especially when they involve large-scale networks with overloaded private information. In this paper, we explored the blockchain-based mechanism that aims to improve the critical features of traditional Internet services, including autonomous and decentralized processing, smart contractual enforcement of goals, and traceable trustworthiness in tamper-proof transactions. Furthermore, we provide a comprehensive review to conceptualize the blockchain-based framework to develop the decentralized protocols for the extensive number of Internet services. This comprehensive survey aims to address blockchain integration to secure Internet services and identify the critical requirements of developing a decentralized trustworthy Internet service. Additionally, we present a case study of the blockchain-based Internet of Things (IoT) for neuro-informatics to illustrate the potential applications of blockchain architectures. Finally, we summarize the trends and challenges of blockchain architectures that benefit a multitude of disciplines across all the Internet service fields of interest.

/pdf/a-survey-on-blockchain-based-internet-service-architecture-26r6r4o3ol.pdf

A Survey on Blockchain-Based Internet Service Architecture: Requirements, Challenges, Trends, and Future

Driven by CA compromises and the risk of man-in-the-middle attacks, new security features have been added to TLS, HTTPS, and the web PKI over the past five years. These include Certificate Transparency (CT), for making the CA system auditable; HSTS and HPKP headers, to harden the HTTPS posture of a domain; the DNS-based extensions CAA and TLSA, for control over certificate issuance and pinning; and SCSV, for protocol downgrade protection. This paper presents the first large scale investigation of these improvements to the HTTPS ecosystem, explicitly accounting for their combined usage. In addition to collecting passive measurements at the Internet uplinks of large University networks on three continents, we perform the largest domain-based active Internet scan to date, covering 193M domains. Furthermore, we track the long-term deployment history of new TLS security features by leveraging passive observations dating back to 2012. We find that while deployment of new security features has picked up in general, only SCSV (49M domains) and CT (7M domains) have gained enough momentum to improve the overall security of HTTPS. Features with higher complexity, such as HPKP, are deployed scarcely and often incorrectly. Our empirical findings are placed in the context of risk, deployment effort, and benefit of these new technologies, and actionable steps for improvement are proposed. We cross-correlate use of features and find some techniques with significant correlation in deployment. We support reproducible research and publicly release data and code.

https://dl.acm.org/doi/pdf/10.1145/3131365.3131401

Mission accomplished?: HTTPS security after diginotar

The level of trust accorded to certification authorities has been decreasing over the last few years as several cases of misbehavior and compromise have been observed. Log-based approaches, such as Certificate Transparency, ensure that fraudulent TLS certificates become publicly visible. However, a key element that log-based approaches still lack is a way for clients to verify that the log behaves in a consistent and honest manner. This task is challenging due to privacy, efficiency, and deployability reasons. In this paper, we propose the first (to the best of our knowledge) gossip protocols that enable the detection of log inconsistencies. We analyze these protocols and present the results of a simulation based on real Internet traffic traces. We also give a deployment plan, discuss technical issues, and present an implementation.

Efficient Gossip Protocols for Verifying the Consistency of Certificate Logs

This book describes the essential components of the SCION secure Internet architecture, the first architecture designed foremost for strong security and high availability. Among its core features, SCION also provides route control, explicit trust information, multipath communication, scalable quality-of-service guarantees, and efficient forwarding. The book includes functional specifications of the network elements, communication protocols among these elements, data structures, and configuration files. In particular, the book offers a specification of a working prototype. The authors provide a comprehensive description of the main design features for achieving a secure Internet architecture. They facilitate the reader throughout, structuring the book so that the technical detail gradually increases, and supporting the text with a glossary, an index, a list of abbreviations, answers to frequently asked questions, and special highlighting for examples and for sections that explain important research, engineering, and deployment features. The book is suitable for researchers, practitioners, and graduate students who are interested in network security.

SCION: A Secure Internet Architecture

Efficient gossip protocols for verifying the consistency of Certificate logs

Adhering to the end-to-end principle even more than the current Internet yields highly available point-to-point communication.

The SCION internet architecture

In a public-key infrastructure (PKI), clients must have an efficient and secure way to determine whether a certificate was revoked (by an entity considered as legitimate to do so), while preserving user privacy. A few certification authorities (CAs) are currently responsible for the issuance of the large majority of TLS certificates. These certificates are considered valid only if the certificate of the issuing CA is also valid. The certificates of these important CAs are effectively too big to be revoked, as revoking them would result in massive collateral damage. To solve this problem, we redesign the current revocation system with a novel approach that we call PKI Safety Net (PKISN), which uses publicly accessible logs to store certificates (in the spirit of Certificate Transparency) and revocations. The proposed system extends existing mechanisms, which enables simple deployment. Moreover, we present a complete implementation and evaluation of our scheme.

/pdf/pki-safety-net-pkisn-addressing-the-too-big-to-be-revoked-x9fw3f4ypf.pdf

Laurent Chuat

Papers

Efficient Gossip Protocols for Verifying the Consistency of Certificate Logs

SCION: A Secure Internet Architecture

Efficient gossip protocols for verifying the consistency of Certificate logs

The SCION internet architecture

PKI Safety Net (PKISN): Addressing the Too-Big-to-Be-Revoked Problem of the TLS Ecosystem