What is a Hashing Function

Hashing functions are mathematical algorithms that take inputs and generate unique outputs.

What is a Good Hashing Function

“The essential characteristics of good hashing algorithms are determinism, noninvertibility and collision resistance.” A good cryptographic hash function is non-invertible, meaning it cannot be reverse engineered.

What is  SHA256 Hash Generator

what is an Immutable transaction

Immutability is used to denote something which can never be modified or deleted. In a blockchain, it refers to the logs of transactions, which is created by consensus among the chain’s participants. The basic notion is this: once a blockchain transaction has received a sufficient level of validation it can never be replaced or reversed or edited.

Now let us see how blockchain attains immutability.

If a miner tries to change a transaction from history, he will have to re-mine all the blocks from that block till the current block and this will have to be reflected in every copy of the ledger in the network. Miners will have to rebuild the merkle tree of the block in which the transaction is present and redo all the proof of work for that block.

Now, since the next block stores the hash of this block, the next block will also have to be re-mined. This is because the next block will have to be edited with the new “previous block hash”. This change will result in a different block hash. The new block hash might result in a hash that does not match the set difficulty level. Thus, this block will also have to be re-mined.

What about the new blocks being added every 10 minutes?

The computing power required to achieve this is enormous and probably only theoretical.

what is a trapdoor function

What is  a Merkle Tree

In very simple terms, a Merkle Tree is a way of structuring data that allows a large body of information to be verified for accuracy both extremely efficiently and quickly. They have become a crucial component of blockchain technology and cryptocurrency,

The Merkle Tree has been around since 1979, when a man named Ralph Merkle was at Stanford University. Merkle wrote a paper titled “A Certified Digital Signature” during his time at Stanford, and unknowingly created a major component of blockchain. In his paper, Merkle described a brand new method of creating proofs. Essentially, Merkle designed a process for verifying data that would allow computers to work much faster than before

A Merkle Tree Example

Let’s imagine that there were four transactions performed on one block: A, B, C, and D. Each transaction is then hashed, leaving us with:

The hashes are paired together resulting in:

These two hashes are hashed together to give us our Merkle Root: Hash ABCD. In reality, a Merkle Tree is far more complicated than this (especially when you consider that each transaction ID is 64 characters long) but this should give you an idea as to how the algorithms work and why it is so effective. 

The implementation of Merkle trees in blockchains has multiple effects. It allows them to scale while also providing the hash-based architecture for them to maintain data integrity and a trivial way to verify the integrity of data.