transaction, an integer has been added to the storage and ten characters have been appended to an existing string in the storage, then ꜩ 18 will be withdrawn from the contract’s balance and destroyed. 3.3.5 Code Thelanguageis stack based, with high level data types and primitives and strict static type checking. Its design is insipired by Forth, Scheme, ML and Cat. Afull specification of the instruction set is available in[3]. This specification gives the complete instruction set, type system and semantics of the language. It is meant as a precise reference manual, not an easy introduction. 3.3.6 Fees Sofar, this system is similar to the way Ethereum handles transaction. However, we differ in the way we handle fees. Ethereum allows arbitrarily long programs to execute by requiring a fee that increases linearly with the program’s execut- ing time. Unfortunately, while this does provide an incentive for one miner to verify the transaction, it does not provide such an incentive to other miners, who must also verify this transaction. In practice, most of the interesting pro- grams that can be used for smart contracts are very short. Thus, we simplify the construction by imposing a hard cap on the number of steps we allow the programs to run for. If the hard cap proves too tight for some programs, they can break the execu- tion in multiple steps and use multiple transactions to execute fully. Since Tezos is amendable, this cap can be changed in the future, or advanced primitives can be introduced as new opcodes. If the account permits, the signature key may be changed by issuing a signed message requesting the change. 4 Conclusion Wefeel we’ve built an appealing seed protocol. However, Tezos’s true potential lies in putting the stakeholders in charge of deciding on a protocol that they feel best serves them. References [1] Vitalik Butterin. Slasher: A punitive proof-of-stake algorithm. https://blog.ethereum.org/2014/01/15/ slasher-a-punitive-proof-of-stake-algorithm/, 2014. [2] Ariel Gabizon Iddo Bentov and Alex Mizrahi. Cryptocurrencies without proof of work. http://www.cs.technion.ac.il/~idddo/CoA.pdf, 2014. 16