Raziel: Private and Verifiable Smart Contracts on Blockchains

Raziel combines secure multi-party computation and proof-carrying code to provide privacy, correctness and verifiability guarantees for smart contracts on blockchains. Effectively solving DAO and Gyges attacks, this paper describes an implementation and presents examples to demonstrate its practical viability (e.g., private and verifiable crowdfundings and investment funds, double auctions for decentralized exchanges). Additionally, we show how to use Zero-Knowledge Proofs of Proofs (i.e., Proof-Carrying Code certificates) to prove the validity of smart contracts to third parties before their execution without revealing anything else. Finally, we show how miners could get rewarded for generating pre-processing data for secure multi-party computation.

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An Optimal ICO Mechanism

Initial Coin Offerings (ICOs) are raising billions in funding using multiple strategies, none justified from the point of view of mechanism design, resulting in severe underpricing and high volatility.
In the present paper, an optimal ICO mechanism is proposed for the first time: a truthful multi-unit Vickrey-Dutch auction of callable tokens (i.e., a new hybrid security of tokens packaged with callable warrants). Truthful bidding is an ex-post Nash equilibrium strategy and the auction terminates with an ex-post efficient allocation; additionally, the callability of the warrants eliminates the winner’s curse of the auction and its underpricing. An implementation demonstrates its practical viability.

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The Valuation of Secrecy and the Privacy Multiplier

How much is secrecy worth and how many times can a secret be sold?
This paper introduces a novel method to properly quantify the value of secrecy for the first time and finds that it is supported by empirical evidence. Additionally, it introduces another novel method to model and quantify the Privacy Multiplier, that is, the additional value obtained from the use of privacy-preserving techniques when offering secret data to potentially distrustful third-parties. Altogether, both results close open questions regarding the quantification of the economic impact of the practical application of secure computation technologies, particularly on blockchains.

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Secure Computation on Spreadsheets

Systems, computer-readable media and methods for enabling secure computation on spreadsheet software. A secure spreadsheet is implemented as an add-in to an existing spreadsheet program, or as a new spreadsheet program/web application, to allow secure computations on private input data (and also optionally with private functions) without the parties learning anything about them, via the familiar spreadsheet interface and its formula language. Automatic conversion of previous spreadsheet data and formulas is provided whenever possible, or assisted via a helper. The secure computation can be executed between the computers of the involved parties, or outsourced to a third-parties, or outsourced to a third-party -cloud-computing system-: the secure cryptographic calculation module automatically optimizes for the best performing technique of secure computation (for example, homomorphic encryption, garbled circuits, oblivious transfers, secret sharing, oblivious random machines and/or a combination of the previous crypto-primitives).

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Cryptographically Secure Financial Instruments

Systems, methods and financial instruments enhanced with secure computation. A financial instrument management system is implemented with secure computation capabilities, respecting the privacy and secrecy rights during computation of the information contained within financial instruments, external datasets and/or secure computation programs. Automatic conversion and aggregation of conventional financial instruments is also disclosed. Furthermore, secure computation programs can be certified with mathematical proofs about very advantageous and valuable properties such as their correct termination, conformance to a specification, or any other pre-conditions, post-conditions and invariants on their inputs and outputs, encrypted or in plaintext form

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