In today’s world, hashing plays a fundamental role in securing our digital interactions. From protecting passwords to verifying data integrity, hashing is at the core of modern encrypted communications. In this article series, we’ll dive into the essentials of hashing, explore its types, and look at its many real-world applications.
What is Hashing?¶
Hashing is a process that transforms input data (often called plaintext) of any length into a fixed-length string of characters. This transformation produces a “hash,” a unique fingerprint of the original data, typically represented by a string of letters and numbers.
The distinct feature of hashing is its irreversibility. Once data is hashed, you cannot easily revert it to its original form. This is because hashing is a one-way function. Although it’s technically possible to guess the input by brute force or through algorithmic flaws (in weaker hashing algorithms), good hashing algorithms are designed to make such efforts practically infeasible.
In hashing:
- For a given input, hashing will always produce the same output (deterministic).
- The hashing process is designed to be computationally efficient, producing results quickly even with large inputs.
Hashing is therefore ideal for many security applications, particularly because of this unique combination of irreversibility, speed, and determinism.
For example, to hash a password like imaginary-password with the SHA-256 hashing algorithm, you can use the following command in Unix-based systems:
echo -n "imaginary-password" | shasum -a 256
This command produces a 256-bit (32-byte) hash value, which is the “fingerprint” of your input text.