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One of the greatest innovations of the last roughly fifteen years has been the blockchain. This is the digital equivalent of a social contract, of sorts, and is a highly successful example of a decentralized collaboration. Decentralized collaborations haven't worked too well offline, so what is the secret?

The answer is security, more precisely digital security, in the form of hash functions and protocols that make the blockchain a one-of-a-kind platform for secure transactions. One of the ways this is achieved is through consensus protocol; the other is with a hash function. In the article, we will find out if these hash functions can be reversed.

What is hashing?

In essence, hashing means using a hashing algorithm to calculate a large number of bits and outputs, consisting of a fixed number of bits. Hashing algorithms can be used for security purposes such as secure transactions. The original data used is called the input data, and the output is called the hash.

To understand hashing, it's necessary to understand the structure of data. In the blockchain, data is structured in two ways; pointers and linked lists. Pointers refer to variables that point the way to other variables; these are indicators pointing the way to correct locations. Linked lists, however, are a sequence of nodes that link up on the blockchain.

It is the process of hashing that gives the blockchain its security. Once data is hashed, a fixed identifier is assigned to the block that is irreversible. This makes the blockchain an extremely secure and unparalleled form of digital transaction.

Solving a hash

These hash functions form the backbone of the security for a blockchain; without them, the network would be susceptible to corruption and malpractice. Therefore, the hashed data is vital to the quality of data on the blockchain and whether or not it is tamper-proof. You might want to solve a hash if you are adding blocks to the chain.

Solving a hash starts with a complex mathematical equation that deals with data in the block header. Before you begin to solve the hash, however, the miner must decide on a suitable nonce. This is done through a trial and error process. The reward for solving a hash is a new block to add to the blockchain. The miner will receive this if they can solve the hash and meet the requirements of the target hash data.

Hash and its protocol

Depending on the blockchain network, there will be a protocol, an algorithm that determines the function and validation of active data. The hash function is closely related to this protocol to ensure security and decentralized authority.

The standard of decentralization on the blockchain is vulnerable, particularly when users want to download a copy of the blockchain. In this case, it's hard for other users to know whether computers on the network have conspired with a new user to present newly forged data.

But that's where the protocol algorithms come in, in collaboration with the hash function. In the past, it was not possible to create a decentralized network without a central authority, but the hash function makes this possible. In essence, it creates a digital fingerprint for data.

Is hashing reversible?

In short, hashing is the process of using an algorithm to transform large quantities of data into a fixed value. This can be achieved with any volume of data, and the output data size can be any length. This is called a hash value – the hash value is fixed and non-reversible.

Encryption is different, and it has a two-way function. You can encrypt data on one end and reverse the encryption on the other. It is technically possible to reverse a hash, too; however, it would require a massive amount of computational power that is unlikely to make it feasible. Hashing is, therefore, a one-way process.

There is a further difference between hashing and encryption. Encryption is designed to safeguard data in transit, but hashing is used to secure data. This is why hashing is so useful for the blockchain; it is a reliable and unalterable way to protect the integrity of the network.

Why deceiving the network doesn't work

Some users and data miners might think it's possible to deceive the network by reversing a hash – it may, technically, be possible, but it's extremely unlikely. Deceiving the network in this way is also unprofitable to miners, and here's why.

When miners create a new block for the chain, they must also provide two hash functions. One is for all transactions in the block; the other serves to provide information on the energy expended creating the block. The compensation in respect of this data is minimal for miners, making the process of hashing less profitable.

The computational power needed to find a valid hash is enormous and would require very expensive equipment. There is also no guarantee that the hash they do find would work; the chances are it will identify a line of invalid blocks. Then, if an invalid block is confirmed in the chain, the other computers on the network will reject it.


The blockchain is an advanced collaboration between users of a network. It created transactions without a centralized authority that are tracked carefully within the structure of the blocks. One of the ways this system is upheld is with hashing.

Hashing refers to the process of calculating a vast quantity of data and paring it down into fixed outcomes that can't be reversed. For this reason, the process is ideal for the security and integrity of the blockchain. Hashing is a one-way process.

There may be some people wondering if a hash can be uncovered or the process of hashing reversed. The answer is that while technically possible, it's highly unlikely. Reverse hashing requires enormous amounts of computational power with uncertain results.


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