Sharing trusted data among trusted stakeholders is very important to large-scale Internet of Things (IoT) applications. However, the entities and organizations involved in IoT naturally lack trusted relationships, which poses significant challenges to the above vision. Specifically, the first challenge is to ensure that the data in the physical world can be objectively and truly injected into the information world of IoT. The second is to ensure the credibility of the entities' identities in IoT. The third is to ensure the authenticity of data, the credibility of identity, and the reliable transmission of data when a third trusted party is unable to provide the expected trusted services. In view of the above challenges, this paper proposes a secure and lightweight triple-trusting architecture (SLTA), which fully uses a blockchain-related supporting technology. The architecture includes an oracle-based data collection mechanism, which ensures that the data collected from edge devices of IoT cannot be modified, and the distributed identity management mechanism, which enhances personal privacy, security, and control of digital identities. Furthermore, a series of innovative designs for applying the blockchain to special large-scale cooperation scenario in IoT are proposed, which is also a part of the key mechanisms of the SLTA. The innovative design includes a new software-defined blockchain structure model and a lightweight Byzantine fault-tolerant algorithm that provides credible support for decentralized data collection, identity management, and data transfer, as well as low-overhead sequential storage mechanism. KEYWORDSblockchain, Internet of Things, large-scale cooperation, trusted data sharing INTRODUCTIONWith the development of supporting technologies and the innovation of application modes, Internet of Things (IoT) has the potential to be one of the most popular paradigms in the era of Internet computing. In IoT 1 ecosystem, every entity equipped with identifying, sensing, networking, and processing capabilities has the ability to communicate with all other entities to accomplish some objective 2 through a multitype communication style. Although very large-scale IoT deployments remain a few years away, IoT is large scale 3 by nature. Medium-scale or even large-scale cooperation among smartThis is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

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The yak is one of the most important and economically useful animals for highlanders. The decline in the yak population requires effective measures for the conservation and multiplication of elite germplasm. A standardized protocol will simplify the freezing and warming of yak embryos in straw and facilitate embryo transfer. In this work, we investigated a one-step protocol that uses a stable basal medium, which comprised a warming medium (1.08 M sucrose) and a freezing medium (EFS40). We also assessed the effects of the new transfer method on embryo survival. A total of 145 yak frozen embryos were thawed in a standard medium system. The one-step protocol led to a high recovery percentage (84.93) of yak embryos that survived vitrification and warming. The in vitro survival rates of these embryos significantly different from those of embryos frozen-thawed via the conventional method. The 95 embryos frozen-thawed via our one-step protocol were then implanted in selected recipients. Thirty-six singleton pregnancies were established. In conclusion, the proposed one-step method is a simple, safe, and standardized freezing-thawing protocol that ensures embryo survival and quality under field conditions. This study establishes new possibilities for the widespread use of embryo transfer in yaks.

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