State channel: UC Model
Background
Coins model
by Iddo Bento, Ranjit Kumaresan
used in Sprites, Perun
Resources
better HTLC
the pessimistic timings to constant time (i.e., independent of the length of the channel path).
Giulio Malavolta, Pedro Moreno-Sanchez, Aniket Kate, Matteo Maffei, Srivatsan Ravi
Scaling Bitcoin 2017
the foundations for privacy and concurrency in PCNs, presenting a formal definition in the Universal Composability framework as well as practical and provably secure solutions
an off-chain channel system that offers a new method for connecting channels that is more efficient than the existing technique of “routing transactions” over multiple channels.
introduces a technique called “virtual payment channels” that avoids involvement of the intermediary for each individual payment
Stefan Dziembowski, Sebastian Faust, Kristina Host´akov´a
Sebastian said that they are working on making the specification closer to the program level.
Aggelos Kiayias and Orfeas Stefanos Thyfronitis Litos
Sprites
$ F_{state}
parameterized by an update function$ U
A key technical contribution: a generic way to capture side effects on the blockchain
model a hybrid world where ideal functionalities and blockchain smart contracts interact, i.e. an ideal functionality can read from and post messages to the blockchain and invoke smart contract methods.
This notion is a natural extension of the global ledger functionality (Bitcoin as a Transaction Ledger), which models the blockchain as a shared resource accessible in both the real and ideal worlds and the commonly-used “coins” model, in which ideal functionalities and parties can both send and receive money
Perun
operate with coins.
a synchronous version of the global UC framework (GUC)
UC with Global Setup