Question

1. What is Blockcahin?

2. What is Peer-to-Peer network?

3. What are the properties of a hash?

4. How the public and private keys work in Public-key Encryption (PKE)?

Answer 1

1. In the simplest of terms, a blockchain is a time-stamped series of immutable data recording that is managed by a cluster of computers not owned by any single entity. Each of these data blocks (i.e. blocks) is secured using cryptographic principles (i.e. chain) and linked to each other. There's no central authority in the blockchain network it's the very essence of a democratic system. Because it's a public and permanent ledger, it's available to anyone and everyone to see the details. Therefore, by its very nature, everything that is built on the blockchain is transparent and all involved are responsible for their actions.

2. Stands for "peer to peer." The "peers" are computer systems in a P2P network that are connected via the Internet to each other. Without the need for a central server, files can be exchanged directly between network systems. In other words, on a P2P network, that computer becomes both a file server and a client.

An Internet connection and P2P software are the only requirements for a computer to join a peer-to-peer network. Kazaa, Limewire, BearShare, Morpheus, and Acquisition are popular P2P software programs. Such applications link to a P2P network, such as "Gnutella," which makes it possible for the machine to reach thousands of other network systems.

3. A good hash function has four main characteristics: 1) The hash value is fully determined by the hashed data. 2) All the input data is used by the hash function. 3) The "uniform" hash function distributes the data throughout the entire set of possible hash values. 4) For identical strings, the hash function produces very different hash values.

4. There are two different linked cryptographic keys (basically long random numbers) in the Public and Private key pair. Below is a Public Key example: what its name suggests is the Public Key-Public Key. It is made available to everyone through a server or directory that is open to the public. The Private Key, on the other hand, must remain confidential to its holders. Since the key pair is mathematically related, anything that is encrypted with a Public Key can only be decrypted by its Private Key and vice versa.