Biblio

Blockchain technology relies on a growing number of globally distributed ledgers known as blockchain. This technology was used for the creation of the cryptocurrency known as bitcoin that allows transactions to be carried out quickly and easily, without the need to use an intermediary "financial institution". The information is sent trough the protocols known as: PoW (Proof of Work) and PoS (Proof of Stake), which must guarantee confidentiality, integrity and availability of the information. The present work shows the result of a bibliographic review on the evolution of the blockchain, the PoW and PoS protocols; as well as the application of these within the framework of Ecuadorian legislation with emphasis on the evolution of risks of the PoW protocol.

Performing a fair exchange without a Trusted Third Party (TTP) was considered to be impossible. With multi party computation and practices like Proof-of-Work (PoW), blockchain accomplishes a fair exchange in a trustless network. Data confidentiality is a key challenge that has to be resolved before adopting blockchain for enterprise applications where tokenized assets will be transferred. Protocols like Zcash are already providing the same for financial transactions but lacks flexibility required to apply in most of the potential use cases of blockchain. Most of the real world application work in a way where a transaction is carried out when a particular action is performed. Also, the zero knowledge proof method used in Zcash, ZKSNARK has certain weaknesses restricting its adoption. One of the major drawbacks of ZKSNARK is that it requires an initial trust setup phase which is difficult to achieve in blockchain ecosystem. ZKSTARK, an interactive zero knowledge proof does not require this phase and also provides security against post quantum attacks. We propose a system that uses two indistinguishable hash functions along with ZKSTARK to improve the flexibility of blockchain platforms. The two indistinguishable hash functions are chosen from SHA3-finalists based on their security, performance and inner designs.

If, as most experts agree, the mathematical basis of major blockchain systems is (probably if not provably) sound, why do they have a bad reputation? Human misbehavior (such as failed Bitcoin exchanges) accounts for some of the issues, but there are also deeper and more interesting vulnerabilities here. These include design faults and code-level implementation defects, ecosystem issues (such as wallets), as well as approaches such as the "51% attack" all of which can compromise the integrity of blockchain systems. With particular attention to the emerging non-financial applications of blockchain technology, this paper demonstrates the kinds of attacks that are possible and provides suggestions for minimizing the risks involved.