CBSA Practice Exam Questions with Answers BTA Certified Blockchain Solution Architect Certification

A chaincode package that was signed at creation can be handed over to other owners for inspection and signing. The workflow supports out-of-band signing of chaincode package.

Stream cipher basically means using a fixed key which replaces the message with a pseudorandom string of characters. It is basically the encryption of each letter one at a time.

Remember, that the block creation time is set to 10 minutes and this can never change. So after a fixed time of approximately 2 weeks or exactly 2016 blocks the difficulty is re-adjusted. Increase in difficulty means target decreases.

An oracle is a well known service that signs transactions if they state a fact and that fact is considered to be true. They may also optionally provide the facts r 3 Corda Technical Whitepaper.

At the time of writing these lines, the Ethereum Blockchain still runs on Proof of Work. When a block is mined, the miner node selects some transactions from a pool of pending transactions. Usually they are sorted by how much gas they would bring in. These transactions are executed and incorporated in the new block. But a block also contains two very important parameters: a difficulty and a timestamp. The difficulty regulates how hard it is to find a block by the miner. The mining time is set to be between 10 and 20 seconds. If it’s beyond 20 seconds, the difficulty is too high and will be automatically lowered going forward. If the mining happens below 10 seconds, then the difficulty increases. The timestamp is the time when a miner found the block. It is not automatically derived, rather it is set by the miner itself and can thus be influenced to a certain degree. The timestamp does not depend on the time zone, as it’s the standard Unix timestamp.

Contracts can call other contracts or send Ether to non-contract accounts by the means of message calls. Message calls are similar to transactions, in that they have a source, a target, data payload, Ether, gas and return data. In fact, every transaction consists of a top-level message call which in turn can create further message calls.

Difficulty and Timestamp block also contains two very important parameters: a difficulty and a timestamp. The difficulty regulates how hard it is to find a block by the miner. The mining time is set to be between 10 and 20 seconds. If it’s beyond 20 seconds, the difficulty is too high and will be automatically lowered going forward. If the mining happens below 10 seconds, then the difficulty increases. The timestamp is the time when a miner found the block. It is not automatically derived, rather it is set by the miner itself and can thus be influenced to a certain degree. The timestamp does not depend on the time zone, as it’s the standard Unix timestamp.

Proof of Stake has the same goal as proof of work—to validate transactions and achieve consensus in the chain—and it uses an algorithm but with a different process. With proof of stake, the creator of a new block “is chosen in a deterministic way, depending on its wealth, also defined as a stake.” Since in a proof of stake system, there is no block reward, but the miners, known as forgers, get the transaction fees. Proponents of this shift, including Ethereum co-founder Buterin, like proof of stake for the energy and cost savings realized to get to a distributed form of consensus.

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.

The main benefits are the anti-DoS attacks defense and low impact of stake on mining possibilities. Defense from DoS attacks. PoW imposes some limits on actions in the network. They need a lot of efforts to be executed. Efficient attack requires a lot of computational power and a lot of time to do the calculations. Therefore, the attack is possible but kind of useless since the costs are too high. Mining possibilities. It doesn’t matter how much money you have in your wallet. What matters is to have large computational power to solve the puzzles and form new blocks. Thus, the holders of huge amounts of money are not in charge of making decisions for the entire network.