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…
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…
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…
It is widely believed that financial markets cannot be liquid without centralised processes to manage counterparty risk. We propose an alternative method for liquidity based on reversible and composable contracts run atop a blockchain. Novel instruments for zero-collateral intermediation can be defined.
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…
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…
