Hash is a mathematical algorithm that functions to convert input values ??of various sizes into outputs (hashes) with a fixed size. In most cases, the output consists of hexadecimal numbers. This means the hash is often denoted as a combination of numbers (0 to 9) and letters (a to f).
A hash function is a mathematical function that converts a numeric input value into a compressed numeric value. The purpose is to compress the input numeric value. The hash function input has various lengths, but the hash value output will always have a fixed length. The value returned by the hash function is called the message digest or simply the hash value.
In cryptography, the word hash refers to the output produced by a hash function after a piece of data has been sent (mapped) through it. In addition to the hash, the output produced by a hash function can also be referred to as a hash value, hash code, or digest.
To better understand what a hash is, it’s worth discussing what a hash function is and how it works.
For example, if we use the word “Binance” as the input value, and map it via the SHA-256 hash function, the output (or hash) value returned is:
Note that no matter how many times we perform this action, the output will always be the same (as long as the input doesn’t change).
On the other hand, any small change to the input will cause the hash function to return a completely different hash as output. For example, if we sent the word “binance” instead of “Binance”, we would have the following hash as a result:
Hashes are useful for verifying the validity of certain information, without revealing what information it is. In practice, hash functions can be applied to a variety of scenarios. Some of the use cases include database search, large file analysis, and data management.
When combined with cryptographic techniques, we have what is called a cryptographic hash function. It is widely used in information security and is an important part of most blockchain networks.
For example, the Bitcoin blockchain has many operations that involve hashing, and this is very important in the mining process.