Fundamentally, hashing is the process of taking the input string of arbitrary length and turning it into a cryptographic fixed-length output. It’s to be noted that “hashing” isn’t an “encryption” and that we cant retrieve the first data by decrypting the hash, it’s a “one-way cryptographic function”.
Example of Blockchain
And if we take the instance of blockchain utilized in cryptocurrencies, transactions of varying lengths are run through a given hashing algorithm, and everybody is given an output that’s of a group length. This output string is independent of the length of the pc file which we fetch into it. The output is what we call a hash.
Secure Hashing Algorithm 256
A good example of this is Bitcoin’s Secure Hashing Algorithm 256 (also called the SHA-256 algorithm). Hashing done using SHA-256 always gives an output result of a fixed length, which has a 256-bits length (and generally the output size is 32 bytes). This is the case where the transaction is just a single word or a complex transaction with a huge amount of data. And always remember the size of the hash will depend on the hash function utilized.
But the output of the hash using a particular hashing algorithm will be of a specific size. That means the hash value of “QueckoInc” and “Blockchain” would be of equal length, no matter how much is the size of the input data. And as we discussed earlier, the process of using a given hash function to process is called hashing and cryptography plays a major role at the heart of it.
Characteristics of Cryptographic Hash Function
Some of the characteristics of those cryptographic hash functions include the following:
- Deterministic: It will always provide you with a hard and fast value output.
- Quick Computation: it’s going to be difficult to seek out the computer file for a hash, but computing or calculating the hash is ideally in no time.
- Pre-image resistance: Given a hash of a specific transaction, it should be virtually impossible or practically infeasible to work out the first computer file using this output. And this property of hashing is some things that lend an honest level of security to the blockchain.
- Randomized: The hash function produces different outputs for each input, whether or not the computer file differs by only a digit or letter. As an example, the hash of the word “Apple” should be completely different from the hash of the word “Apple1”.
- Collision Resistance: If a hash function gives the identical value for two or more unique inputs, it’s called a collision, and Cryptographic hash functions are supposed to have collision-resistant properties, that is, they must never have an identical output for 2 or more unique inputs.
Now, as we’ve understood the basics of hashing, let’s take a deep dive into how hashing in blockchain works.
Hashing in Blockchain
As we all know that the blockchain may be a sequence of blocks… each block in it contains data and contains a hash pointer that points to its previous block, hence making the blockchain. This hash pointer contains the hash of all the info inside the previous block, and this small feature is what makes blockchains so popular and revolutionary.
And here, if a hacker attacks block 3 and tries to vary the data… because of the properties of hash functions even a small change in data changes the hash drastically, this suggests that any change made in block 3 will change the hash stored in block 2… this, in turn, will change the information and therefore the hash of block 2, which ends in a change in block 1…And so on….This contributes to what exactly we call immutability within the blockchain. Any tiny changes within the data are immediately noticed and nullified by each preceding block and this can be how essentially, the concept of blockchain hashing plays a task in blockchain technology.
Lastly, as a conclusion, I’d say that the cryptographic hash function is an integral part of blockchain innovation and it’s essentially a feature that offers security and capabilities to the processed transactions, making them immutable.