Transport Layer Security (TLS) 1.3 is a redesign of the Web's most important security protocol. It was standardized in August 2018 after a four year-long, unprecedented design process involving many cryptographers and industry stakeholders. We use the rare opportunity to track deployment, uptake, and use of a new mission-critical security protocol from the early design phase until well over a year after standardization. For a profound view, we combine and analyze data from active domain scans, passive monitoring of large networks, and a crowd-sourcing effort on Android devices. In contrast to TLS 1.2, where adoption took more than five years and was prompted by severe attacks on previous versions, TLS 1.3 is deployed surprisingly speedily and without security concerns calling for it. Just 15 months after standardization, it is used in about 20% of connections we observe. Deployment on popular domains is at 30% and at about 10% across the com/net/org top-level domains (TLDs). We show that the development and fast deployment of TLS 1.3 is best understood as a story of experimentation and centralization. Very few giant, global actors drive the development. We show that Cloudflare alone brings deployment to sizable numbers and describe how actors like Facebook and Google use their control over both client and server endpoints to experiment with the protocol and ultimately deploy it at scale. This story cannot be captured by a single dataset alone, highlighting the need for multi-perspective studies on Internet evolution.

Recent standardization efforts focus on a number of lightweight IP security protocol variants for end-to-end security in the Internet of Things (IoT), most notably DTLS, HIP DEX, and minimal IKEv2. These protocol variants commonly consider public-key-based cryptographic primitives in their protocol design for peer authentication and key agreement. In this paper, we identify several performance and security issues that originate from these public-key-based operations on resource-constrained IoT devices. To illustrate their impact, we additionally quantify these protocol limitations for HIP DEX. Most importantly, we find that public-key-based operations significantly hamper a peer's availability and response time during the protocol handshake. Hence, IP security protocols in the IoT must be tailored to reduce the need for expensive cryptographic operations, to protect resource-constrained peers against DoS attacks targeting these cryptographic operations, and to account for high message processing times. To this end, we present three complementary, lightweight protocol extensions for HIP DEX: i) a comprehensive session resumption mechanism, ii) a collaborative puzzle-based DoS protection mechanism, and iii) a refined retransmission mechanism. Our focus on common protocol functionality allows to generalize our proposed extensions to the wider scope of DTLS and IKE. Finally, our evaluation confirms the considerable achieved improvements at modest trade-offs.

The emerging Internet of Things (IoT) promises value-added services for private and business applications. However, especially the industrial IoT often faces tough communication latency boundaries, e.g., to react to production errors, realize human-robot interaction, or counter fluctuations in smart grids. Simultaneously, devices must apply security measures such as encryption and integrity protection to guard business secrets and prevent sabotage. As security processing requires significant time, the goals of secure communication and low latency contradict each other. Especially on constrained IoT devices, which are equipped with cheap, low-power processors, the overhead for security processing aggregates to a primary source of latency. We show that antedated encryption and data authentication with templates enables IoT devices to meet both, security and low latency requirements. These mechanisms offload significant security processing to a preprocessing phase and thus decrease latency during actual transmission by up to 75.9 %. Thereby they work for well-established security-proven standard ciphers.

Since the introduction of Bitcoin in 2008, blockchain systems have seen an enormous increase in adoption. By providing a persistent, distributed, and append-only ledger, blockchains enable numerous applications such as distributed consensus, robustness against equivocation, and smart contracts. However, recent studies show that blockchain systems such as Bitcoin can be (mis) used to store arbitrary content. This has already been used to store arguably objectionable content on Bitcoin's blockchain. Already single instances of clearly objectionable or even illegal content can put the whole system at risk by making its node operators culpable. To overcome this imminent risk, we survey and discuss the design space of countermeasures against the insertion of such objectionable content. Our analysis shows a wide spectrum of potential countermeasures, which are often combinable for increased efficiency. First, we investigate special-purpose content detectors as an ad hoc mitigation. As they turn out to be easily evadable, we also investigate content-agnostic countermeasures. We find that mandatory minimum fees as well as mitigation of transaction manipulability via identifier commitments significantly raise the bar for inserting harmful content into a blockchain.