The term hash in cryptography refers to the output of a hash function after a piece of data is submitted (mapped) through it. In addition to the hash, the output of hash functions can be referred to as hash value, hash code, or digest.
Scroll down to get a full detailed explanation of what a hash is and how it works if you don’t understand what it is.
What Is Hash?
A hash, also known as a hash function, is a mechanism for converting arbitrary data of any length into a fixed-length counterpart. When an algorithm generates results that are represented as hash values, hash codes, hash sums, checksums, or hashes, it is referred to as a hash function.
There has been recent development of payment networks that use the internet, such as Bitcoin, which uses a hash function known as ‘hashing’ and has given new meaning to the phrase ‘hashing.’
Because hash functions can handle variable-length inputs, they can also return fixed-length outputs. A cryptographic hash function combines several hash features, such as message transmission, with added security.
How Hash Function Works
Typical hash functions accept variable-length inputs and return fixed-length outputs. The message-passing capabilities of hash functions are combined with security properties in a cryptographic hash function.
Hash functions are commonly used data structures in computing systems for tasks like message integrity checking and information authentication. They are not easily decipherable, despite being considered cryptographically “weak” because they can be solved in polynomial time.
Cryptographic hash functions augment traditional hash functions with security features, making it more difficult to decipher the contents of a message or information about recipients and senders.
Features of Hash Functions
Among the main characteristics of the hash functions, the following can be mentioned:
- They are easy to calculate. Hashing algorithms are very efficient and do not require large computing power to run.
- It is compressible. This means that regardless of the size of the data input, the result will always be a fixed-length string. In the case of SHA-256, the string will be 64 characters long.
- Avalanche-type operation. Any slight change in data entry results in a different hash than the original data entry.
- Weak and strong resistance to collisions. It refers to the fact that it is impossible to calculate a hash, which allows finding another equal hash. Better known as pre-image y second preimage is the basic concept of hash security.
- They are irreversible. Taking a hash and obtaining the data that gave rise to it, in practice may not be possible. This is one of the principles that make hashes safe.
History of Hash functions
The first hash function was introduced in the year 1961. Wesley Peterson invented the Cyclic Redundancy Check function back then. It was designed to verify the accuracy of data transmitted over networks (such as the Internet) and on digital storage systems.
It quickly gained acceptance and is now an industry standard due to its ease of implementation and speed. These systems became increasingly specialized as computing and computers evolved.
This allowed the creation of new and better hash functions, among which we can highlight:
- MD2: It is one of the first cryptographic hash functions. Created by Ronald rivest, in the year 1989. With a high level of efficiency and security for the moment, it was essential in Internet security.
Its consequent evolution led to the creation of the hash function MD5. Which is still used in environments where safety is not a high priority.
- RIPEMD: is a cryptographic hash function created by the European project RIPE In the year of 1992. Its main function was to replace the current standard, the hash function MD4. Currently, it is still considered very safe, especially in its versions. RIPE MD-160, RIPE MD-256 y RIPEMD-320.
- SHA: the current standard for cryptographic hashes. Created by the NSA en 1993, as part of its internal project to authenticate electronic documents. SHA and its derivatives are considered the most secure hash functions so far. It is of special interest, SHA-256 for being fundamental in the technology that made Bitcoin possible.
What Is a Hash Function?
Hash functions are mathematical functions that transform or “map” a given set of data into a bit string of fixed size, also known as the “hash value.”
How Is a Hash Value Calculated?
A hash function utilizes complex mathematical algorithms that convert data of arbitrary length to data of fixed length (for instance, 256 characters). If you change one bit anywhere in the original data, the entire hash value changes, making it useful for verifying the fidelity of digital files and other data.
Hashes can be used to validate the validity of information without revealing what the information is. In practice, hash functions can be used in a variety of scenarios. Database lookups, large file analysis, and data management are a few examples of use cases.