Test Flashcards
11 cards from real Blockchain Technology practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 11 Test flashcards as text
Which is not popular consensus algorithm in the list
Answer: Digital workforce
PBFT (Practical Byzantine Fault Tolerance), Proof-of-Work, and Proof-of-Stake are all well-established and widely used consensus algorithms in blockchain technology. 'Digital workforce' is a term related to human or automated labor, not a mechanism for achieving agreement on the state of a distributed ledger. Therefore, it is not a popular consensus algorithm in the blockchain domain.
Why is Blockchain a trusted approach?
Answer: All of the above
Blockchain is considered a trusted approach due to its inherent security features, including cryptographic hashing and immutability, which prevent data tampering. Its open-source nature often promotes transparency and compatibility with other applications, fostering wider adoption and scrutiny. The decentralized structure also eliminates single points of failure and the need for intermediaries, collectively building a high degree of trust.
Is it possible to modify the data once it is written in a block?
Answer: No, it’s not possible to do so
No, it is not possible to modify data once it has been written into a block and that block is added to the blockchain. This immutability is a core security principle of blockchain, enforced by cryptographic links between blocks. Any alteration to a past block would change its hash, invalidating all subsequent blocks and making the tampering immediately detectable and rejected by the network.
Is it possible in Blockchain to remove one or more block from the networks?
Answer: Yes, it can be done
While individual blocks are immutable, it is technically possible to effectively 'remove' blocks from the *active* chain through certain network events. A hard fork can create a new, incompatible chain that disregards previous blocks, or a 51% attack can allow an attacker to reorganize the blockchain's history, making certain blocks appear to be removed from the longest chain. However, this doesn't erase the data, but rather changes the network's agreed-upon history.
What are the common types of records that can be kept on the Blockchains?
Answer: All of these
Blockchains are highly versatile distributed ledgers capable of securely and transparently storing a wide array of record types. This includes financial transactions, medical records for enhanced privacy and data sharing, and identity management systems for verifying credentials. Their immutable and decentralized nature makes them suitable for any data requiring high integrity, transparency, and trust across various industries.
_______ is a data structure that is used for verifying a block. It is in the form of a binary tree containing cryptographic hashes of each block
Answer: Merkel Tree
A Merkle Tree, also known as a hash tree, is a fundamental data structure used in blockchain to efficiently verify the integrity of large datasets, such as all transactions within a block. It organizes cryptographic hashes in a hierarchical, binary tree structure. This allows for quick and secure verification of any specific transaction's inclusion in a block without needing to download and process the entire block's data.
In this stage and individual evaluates all requirements and decides a suitable blockchain platform to be implemented.
Answer: Planning stage
The planning stage is the initial phase of a blockchain project where all requirements are evaluated, and a suitable blockchain platform is chosen. This critical step involves defining the project's scope, objectives, and technical specifications to ensure the selected technology aligns with the business needs. Proper planning is essential for the successful development and implementation of any blockchain solution.
What are the parts of EVM memory
Answer: Storage, Memory and Stack
The Ethereum Virtual Machine (EVM) manages data during smart contract execution using three primary memory areas. 'Storage' is persistent and stores the contract's state on the blockchain. 'Memory' is volatile and used for temporary data during function calls, clearing after execution. The 'Stack' is also volatile and used for executing operations and holding small, temporary values.
Name some leading open source platforms for developing Blockchain applications.
Answer: All of the above
Ethereum, Eris (now part of Monax), and Hyperledger are all prominent open-source platforms widely utilized for developing blockchain applications. Ethereum is renowned for its smart contract capabilities and public network, while Hyperledger offers enterprise-grade frameworks for permissioned and consortium blockchains. Eris/Monax provides tools for building private blockchain applications, making all three leading choices in the field.
The ________ is a random value which is used to vary the value of the hash in order to generate hash value less than the target
Answer: Nonce
In Proof-of-Work (PoW) blockchains, a 'nonce' (number only used once) is a variable that miners repeatedly adjust and combine with block data. The goal is to find a nonce that, when hashed with the block's content, produces a resulting hash value that meets a specific difficulty target. This process is central to solving the cryptographic puzzle and validating a new block.
The _______ is the first block in the Blockchain which is also known as block 0
Answer: Genesis block
The Genesis block is the very first block ever created in a blockchain, often designated as block 0. It serves as the foundational block upon which all subsequent blocks are cryptographically linked and built. This initial block contains the fundamental parameters and initial state that define the entire blockchain's existence.