Table of Contents
Key Takeaways:
- Hashing takes any data of any size and transforms it into a fixed-length code, called a hash. This code is nearly impossible to reverse back to the original data, but any changes to the data will result in a completely different hash.
- The three key components of hashing are the key (a unique data identifier), the hash function (transforms the key into an index), and the hash table (stores data as key-value pairs for efficient retrieval).
- In blockchain, hashing secures transactional information, ensuring data integrity and maintaining the immutability of the chain.
Hashing is a fundamental technique in cybersecurity. When sending information through an open network, there’s always a risk of bad actors altering the message’s content before it reaches its intended 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.
But how can one create a unique signature suitable for datasets of varying types and sizes? The answer lies in hash values, which are generated through the hashing process, offering a robust solution to this challenge.
What Is Hashing?
Hashing is a process that transforms data of any size (often called a “message”) into a fixed-length string of characters, known as a hash code or hash value. This transformation is achieved using a mathematical algorithm called a “hash function.”
The key benefit of hashing lies in its ability to create unique identifiers for data. This means the resulting hash value acts like a digital fingerprint for the original data. Any change to the data, however minor, will result in a completely different hash value. This makes hashing a valuable tool for ensuring data integrity and security.
Top 3 Components of Hashing
Understanding the fundamental components of hashing is essential for anyone looking to grasp the intricacies of data structures and algorithms. The three primary components of hashing include the: key, hash function, and hash table.
- Key: The key is the foundational element in hashing, representing the original data intended for storage or retrieval. Within structures like hash tables, the key uniquely identifies and determines the index for storing the corresponding data value, ensuring each data piece receives a unique position within the hash table.
- Hash Function: This is a mathematical algorithm that takes a key as its input and outputs an index for storing or locating the associated value in the hash table. Its main role is to distribute keys uniformly across the hash table, thereby reducing collisions (scenarios where multiple keys yield the same index). An effective hash function is crucial for the swift retrieval of data, as it consistently assigns unique indexes to different keys.
- Hash Table: Also known as a hash map, the hash table is an advanced data structure that employs an associative array for storing and retrieving data via key-value pairs. The hash function processes the key to produce an index within the hash table. The system then stores the value associated with that key at that index. With proper design and management, hash tables can achieve constant-time average complexity for search operations, making them highly efficient for data storage and retrieve.
How Does Hashing Help Secure Blockchain Technology?
Hashing secures blockchain technology by providing a way to encrypt data and maintain the blockchain’s integrity and security. Every block in a blockchain contains a unique hash of its own data, as well as the hash of the previous block. This linkage creates a secure chain of blocks, making it nearly impossible to alter any single block without altering every subsequent block, which would require an impractical amount of computational power. Hashing ensures that each block is permanently recorded and tamper-evident, protecting the blockchain from fraudulent activities and unauthorized modifications. This cryptographic chain of hashes acts as the backbone of blockchain security, safeguarding the data’s authenticity and the entire system’s trustworthiness.
SHA 256: The 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 function (CHF) generates a cryptographic hash. This specialized function has several properties that make it a secure hash function for cryptography. To consider a cryptographic hash function secure, it must have the following characteristics:
- 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. Notably, the output’s length shouldn’t correlate with the input’s size.
- Deterministic Nature: 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.
- Collision Resistance: It should be difficult or nearly impossible to find two different input data sets that produce the same hash value.
- 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.
- One-Way Functionality (Non-reversibility): The process cannot be reversed to obtain the original input data from the hash value. Old hash functions such as MD5 and SHA1 have become reversible due to increased computing power. However, advanced cryptographic hash functions like SHA256 and SHA512 remain non-reversible.
- Non-predictable: Neither the input data nor the original message should predict the generated hash value.
- 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.
Exploring Hashing with MD5 and SHA-256 Calculators
MD5 Hash Calculator
The MD5 Hash Calculator serves as an excellent tool to understand hashing. It demonstrates how different inputs are transformed into distinct hash values:
| Input | MD5 Hash Output |
| Yes | 93cba07454f06a4a960172bbd6e2a435 |
| You’re Welcome | 9f7f6591bb6d38fbe837a3d9cbccbdef |
| What is Hashing (hash) in Blockchain? | 02231844640a61b9f5710793d228a5a1 |
These examples highlight hashing’s unique capability: generating fixed-length, unique hash outputs from various inputs. This feature is crucial for maintaining data integrity and security in digital environments.
SHA-256: Enhancing Security in Blockchain
SHA-256, a robust cryptographic hash function, is essential in blockchain technologies like Bitcoin. It excels in processing large data volumes, converting extensive inputs into manageable, fixed-size hashes. This efficiency is crucial in handling complex transactions within the blockchain.
The strength of SHA-256 lies in its sensitivity to input changes. Even a minor alteration, such as a change in letter case, results in a completely different hash value. Observe these examples using the SHA-256 hash calculator:
| Input | Hash Output |
| Good | c939327ca16dcf97ca32521d8b834bf1de16573d21deda3bb2a337cf403787a6 |
| good | 770e607624d689265ca6c44884d0807d9b054d23c473c106c72be9de08b7376c |
The sensitivity of the hashing process is evident in the fact that a single character change in the input results in a completely different hash value. This consistency ensures that the hash value remains the same regardless of the number of times the input is entered. This unwavering nature is a cornerstone of blockchain technology, enabling effortless verification of data integrity and authenticity.
Blockchain technology makes data on the blockchain immutable, causing any unauthorized modifications readily detectable. This feature is essential for safeguarding the integrity and security of blockchain-based transactions.
What Are Hashed Identifiers?
Hashed identifiers are fundamental in systems designed with a privacy-first approach. These identifiers result from applying a hashing process to sensitive information, such as usernames or email addresses, converting them into distinct, unrecognizable formats. This method is crucial for protecting the original data’s confidentiality. Consequently, even if a data breach occurs, the original information remains secure, conceiled by its hashed version.
The utility of hashed identifiers is demonstrated during the process of user account creation. Instead of directly storing a user’s email address, the system generates a hashed value by running the email address through a hash function. During login, the system re-applies the hash function to the input email address and compares it against the pre-stored hash value. Access is granted if there’s a match between the two hash values. This mechanism ensures that, in the event of unauthorized database access, intruders encounter only the hashed representations, rather than the actual email addresses.
Ultimately, hashed identifiers act as a safeguard, preventing sensitive information from being compromised. Their application extends across various fields, including user authentication, secure data storage, and in ensuring the confidentiality of communications.
Conclusion
Cryptographic hash functions can further protect data integrity. If you question the authenticity or receive a different variant of data, you can process all received data through the cryptographic hash function. Then, compare the resulting hash value with the published one.
For example, when Microsoft releases free software available for download from multiple websites, Microsoft isn’t the sole custodian of this software installer. Other developers might modify it. To avoid malware or compromised software installers, a user should generate a hash value for each copy of the software downloaded. They can then compare it with the hash value provided on Microsoft’s official website.
Blocks in a blockchain apply a similar procedure. Each new block stores the hash value of the previous block to maintain the chain and safeguard the integrity of all preceding blocks. If someone alters a block, its hash value changes. This discrepancy means the next block won’t match the altered block because their hash values don’t align. To achieve alignment, one must also modify the subsequent block. However, changing that block also changes its hash value, necessitating changes to the next block, and so on. 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.
At their core, hash values might appear straightforward. However, they serve as the backbone of the blockchain system, crucially ensuring data remains intact and resistant to 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.