Sending information through an open network can be risky, as bad actors may alter the message’s content before it reaches its destination. However, decentralized networks, such as blockchain, offer a promising solution. A unique signature is necessary to ensure the authenticity and originality of data sent or received. The question remains: how can a unique signature be created for datasets of any type or size? Hash values generated through hashing provide a lasting solution to this question.

How Does Hashing (hash) Work?

Hashing is a process that involves taking an input string of any length and producing an output of a fixed length using a mathematical function called the “Hash Function“. This function generates a fixed value length, also known as an alphanumeric output. The hash value can be used to verify the authenticity of data during transmission, protecting the content of messages during transmission.

In the case of cryptocurrency transactions, hashing is used to generate a fixed-length output when sending cryptocurrency from one user to another. Regardless of the length of the input, the hash algorithm produces an output of the same fixed length.The examples below, as converted through MD5 Hash Calculator, demonstrate that the length of the input doesn’t determine the length of the output (hash value):

Bitcoin, the leading cryptocurrency, uses the Secure Hash Algorithm (SHA) 256 hashing algorithm. Regardless of the length of the input data, the output or hash value remains fixed at 256 bits. This is particularly useful in transactions where large amounts of data need to be handled. Rather than keeping track of the extensive input data, it is easier to keep track of the fixed hash value or output.

One of the most significant benefits of hashing is its ability to detect even the tiniest change in a file. For instance, a simple letter capitalization will result in a different hash value. This makes it an essential tool for ensuring data integrity and authenticity, particularly in secure transactions like those carried out with Bitcoin. Can you spot the difference in the hash value of the examples below using the SHA-256 hash calculator:

The change of just one letter in the input produces an entirely different hash value, demonstrating the sensitivity of the hashing process. Additionally, it remains constant, regardless of how many times a particular input is entered. As long as the information or data remains unchanged, the same hash value will be obtained. You can also input the words above in the SHA-256 hash calculator to obtain the same result.

This level of rigidity and consistency is one of the backbones of blockchain technology, making data protection and authenticity easy to verify. With this technology, data on the blockchain is immutable, and any tampering by a user or node is easily detected. This is a crucial feature for ensuring the integrity and security of transactions carried out using blockchain.

SHA 256 — Secure Hash Algorithm

The Secure Hash Algorithm (SHA 256) is one of the most robust cryptographic hash functions currently available. Cryptographic hashes act as digital signatures for data sets. A cryptographic hash is generated using a cryptographic hash function (CHF), a specialized function with several properties that qualify it as a secure hash function for cryptography. For a cryptographic hash function to be considered secure, it must possess the following properties:

1. Quick Computation and Compression — The hash function should be able to quickly calculate and compress data regardless of the input size and produce a fixed-length hash value. The output length should not be related to the input length.
2. Deterministic —The same input data must always produce the same hash value. If the hash value changes for the same data set, verifying data authenticity will be unreliable. However, consistent hash values make it easier to keep track of input data.
3. Collision Resistance — It should be difficult or nearly impossible to find two different input data sets that produce the same hash value.
4. Pre-Image Resistance — Finding the input data from the output hash value should be computationally hard. This makes it difficult for hackers to reverse the hash value to obtain sensitive information such as passwords or transmitted data.
5. Non-reversibility, or One-Way Function —The process cannot be reversed to obtain the original input data from the hash value. While old hash functions such as MD5 and SHA1 have become reversible due to increased computing power, advanced cryptographic hash functions like SHA256 and SHA512 remain non-reversible.
6. Non-predictable — Neither the input data nor the original message should predict the generated hash value.
7. Diffusion or Avalanche Effect — Minor changes in the input data should lead to significant changes in the hash value. Even capitalization or digit changes should result in more than a 50% change in the output hash value.

Conclusion

Cryptographic hash functions can further protect data integrity. If there are doubts about the authenticity or a different variant of data is received, all received data can be processed through the cryptographic hash function, and the given hash value can be compared with the published hash value.

For instance, Microsoft releases a piece of free software that can be downloaded from multiple websites, meaning that not only Microsoft is the custodian of this software installer, as other developers can modify it. In order to avoid malware or compromised software installers, a user only needs to generate a hash value for each copy of the software downloaded and compare it with the hash value given on Microsoft’s official website.

A similar procedure is applied in blocks that make up a blockchain, as the previous block’s hash value is stored in the new block to keep the chain of blocks going and protect the integrity of all past blocks. As soon as one block is altered, its hash value will change, which means the following block won’t agree with it since the previous block’s hash value didn’t align with the following block’s hash value. This means the following block needs to be altered for there to be an alignment. Altering the following block will also alter its hash value, so the next block must also be modified. The same scenario will play out for the hundreds and thousands of blocks on that blockchain (blockchains like Ethereum have millions of blocks). Repeating this process for all linked blocks is practically impossible. 

Hash values may seem simple, but they are a key component of the blockchain system and play an important role in ensuring data integrity and protecting against tampering.

Identity.com

Blockchain is the future, and it is impressive to see Identity.com contributing to this desired future through the Solana ecosystem and other Web3 projects. Also, as a member of the World Wide Web Consortium (W3C), the standards body for the World Wide Web.

Identity.com, as a future-oriented company, is an open-source ecosystem providing access to on-chain and secure identity verification for businesses,  giving their customers a hassle-free experience. Our solutions improve the user experience and reduce onboarding friction through reusable and interoperable Gateway Passes. Please refer to our docs about how to help you with identity verification and general KYC processes.