Free Blockchain BTA Certified Blockchain Solution Architect CBSA Exam Questions

A proof of work system is vulnerable to a particular type of attack called the ''P+ epsilon attack''. In order to understand how this attack works we must define some terms before hand. Un-Coordinated Choice Model: An uncoordinated choice model is a model where all the participants don't have the incentive to work with one another. The participants may form groups but at no time is the group big enough to become a majority.

Ethereum Smart Contracts run on compiled bytecode, which means that there can be several high-level languages which code can be written in. In particular, Ethereum has a number of languages available: 1. Solidity -- the most popular language now (2018). 2. Vyper -- A Language by Vitalik Buterin with an emphasis on security 3. LLL -- ''Low Level Lisp-like Language'' 4. Mutan -- Golang-like, deprecated in 2015 5. Serpent, Python-like, but seems to be no longer maintained 6. Bamboo

Review Technical Whitepaper https://www.corda.net/ Corda network has one or more notary services which provide transaction ordering and timestamping services, thus abstracting the role miners play in other systems into a pluggable component.

SHA-2 consists of a set of 6 hashing algorithms, and is considered the strongest. SHA-256 or above is recommended for situations are security is vital. SHA-256 produces 32-byte hash values.

EVM The Ethereum Virtual Machine (EVM) is the runtime environment for smart contracts in Ethereum. It is not only sandboxed, but actually completely isolated, which means that code running inside the EVM has no access to network, filesystem, or other processes. Smart contracts even have limited access to other smart contracts.

Corda does not share the same requirements as Bitcoin: we require absolute certainty over transaction finality and we need to know who our counterparts are. So we had the freedom -- and took this opportunity -- to solve the consensus problem in a different way. In particular, Corda solves the privacy issue in a number of manners, primarily by allowing for separation of consensus into a service which we call the Notary Cluster. Corda was designed for business from the start. It has no cryptocurrency built into the platform and does not require mining-style consensus, which imposes great cost with little business benefit.

Sidechain is another name for blockchains that run adjacent to Bitcoin and offer more scope for processing contracts.