Fundamental Pricing of Utility Tokens

We propose a framework for the fundamental valuation of utility tokens. Our model endogenizes the velocity of circulation of tokens and yields a pricing formula that is fully microfounded. According to our model, tokens are valuable because they have to be immediately accessible when the services are needed, a requirement...

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2-Step Multi-Client Quadratic Functional Encryption from Decentralized Function-Hiding Inner-Product

In this paper, we present a multi-client quadratic functional encryption (MCQFE) scheme from function-hiding inner-product (FHIP). The main challenge in such construction is that all the clients require the access to the master secret key of the underlying FHIP scheme, which clearly breaches the security. To overcome this challenge, we...

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Multi-Client Inner-Product Functional Encryption in the Random-Oracle Model

Multi-client functional encryption (MCFE) is an extension of functional encryption (FE) in which the decryption procedure involves ciphertexts from multiple parties. In this paper, we consider MCFE schemes supporting encryption labels, which allow the encryptor to limit the amount of possible mix-and-match that can take place during the decryption. This...

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Efficient Lattice-Based Inner-Product Functional Encryption

In the recent years, many research lines on Functional Encryption (FE) have been suggested and studied regarding the functionality, security, or efficiency. These studies include quadratic FE, multi-client FE, function-hiding FE, dynamic FE and much more. Nevertheless, an open problem on a basic functionality, the single-input inner-product (IPFE), remains: can...

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Double-Authentication-Preventing Signatures in the Standard Model

A double-authentication preventing signature(DAPS)scheme is a digital signature scheme equipped with a self-enforcement mechanism. Messages consist of an address and a payload component, and a signer is penalized if she signs two messages with the same addresses but different payloads. The penalty is the disclosure of the signer’s signing key....

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Practical solutions to save bitcoins applied to an identity system proposal

In a recent work by Augot et al. (2017), a scheme is proposed to build an identity system on top of the Bitcoin network. However, this proposal incurs very high costs since Bitcoin transactions require heavy fees. The current work introduces modifications to their scheme to make it more cost...

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Cryptocurrencies, Currency Competition, and the Impossible Trinity

We analyze a two-country economy with complete markets, featuring two national currencies as well as a global (crypto)currency. If the global currency is used in both countries, the national nominal interest rates must be equal and the exchange rate between the national currencies is a risk-adjusted martingale. We call the...

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