Pairing-based cryptography (PBC) has recently received much attention, since the mathematical building block of pairings paved the ground for devising efficient cryptographic protocols exploiting an old inspiration, i.e., to produce the public key of an entity based on its identity. The so-called Identity-Based Cryptography (IBC) simplifies key management procedures, since it does not require certificate-based infrastructures. Moreover, it is an elliptic curve cryptosystem which entails that it offers the same security levels as other public key systems with much smaller key lengths. The above characteristics make it an attractive solution for resource-constrained environments such as the Internet of Things (IoT), where strong confidentiality and signature schemes are necessary. In this article, we conducted feasibility tests of pairing-based cryptography for middle-class IoT devices, such as the Raspberry Pi 3 platform.

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We propose a new theoretical approach for building anonymous mixing mechanisms for cryptocurrencies. Rather than requiring a fully uniform permutation during mixing, we relax the requirement, insisting only that neighboring permutations are similarly likely. This is defined formally by borrowing from the definition of differential privacy. This relaxed privacy definition allows us to greatly reduce the amount of interaction and computation in the mixing protocol. Our construction achieves O(n·polylog(n)) computation time for mixing n addresses, whereas all other mixing schemes require O(n 2) total computation across all parties. Additionally, we support a smooth tolerance of fail-stop adversaries and do not require any trusted setup. We analyze the security of our generic protocol under the UC framework, and under a stand-alone, game-based definition. We finally describe an instantiation using ring signatures and confidential transactions.