Understanding Hashing.
Next huge topic I went through was Hashing. In this blog I’ll cover the hashing in detail.
Hashing is a fundamental concept in computer science and data management that we often encounter in various applications, from password storage to data retrieval. Let’s explore what hashing is, how it works, its types, and its applications. Let's dive in together!
What is Hashing?
At its core, hashing is the process of transforming any given input (like a string of characters) into a fixed-length output. This output, known as a hash value or hash code, serves as a unique identifier for the input data. The beauty of hashing lies in its ability to condense data into a manageable size while ensuring that even the slightest change in the input results in a significantly different hash value. This property is crucial for maintaining data integrity and security.
How Does Hashing Work?
The hashing process typically involves three main steps:
Input Data: We begin with an input of any length and format, which can be anything from a simple string to complex files.
Hash Function: A hash function applies a series of mathematical operations to the input data. This function must be deterministic, meaning it will always produce the same hash value for the same input.
Hash Output: The output is a fixed-length string that represents the original input. Importantly, it is computationally infeasible to reverse-engineer the original input from the hash output.
For example, if we take the string "hello" and apply a hash function like SHA-256, we get a unique hash value that looks something like this: 2cf24dba5fb0a30e26e83b2ac5b0b6c7d1c0f0e3a4c8e6c3d9c4f1a2f4f4d5a3.
Types of Hash Functions
There are several types of hash functions used in different contexts:
Cryptographic Hash Functions: These are designed for security purposes. They ensure that even small changes in input yield drastically different outputs, making them suitable for password storage and digital signatures.
Non-Cryptographic Hash Functions: Often used in data structures like hash tables, these functions prioritize speed and efficiency over security.
Checksums: Simple hash functions used primarily for error-checking in data transmission.
Applications of Hashing
Hashing has numerous applications across various fields:
Data Retrieval: Hash tables use hashing to store key-value pairs efficiently, allowing for quick access and retrieval.
Password Storage: By hashing passwords before storing them in databases, we enhance security. Even if an attacker gains access to the database, they cannot easily retrieve the original passwords.
Data Integrity Checks: Hashing helps verify that data has not been altered during transmission or storage by comparing hash values before and after the process.
Digital Signatures: In cryptography, hashing is used to create unique signatures for documents and transactions.
Adding Salt to Hashing
To further enhance security, especially when dealing with passwords, we can add a technique known as salting. Salting involves appending a unique random string (the salt) to each password before hashing it. This ensures that even if two users have the same password, their hashed values will be different due to the unique salts added.
For instance:
User: Bob
Password:
farm1990M0OSalt:
f1nd1ngd0rySalted Input:
farm1990M0Of1nd1ngd0ryHash (SHA-256):
11c150eb6c1b776f390be60a0a5933a2a2f8c0a0ce766ed92fea5bfd9313c8f6
This approach not only makes it more challenging for attackers but also enhances overall security by requiring them to compute hashes individually for each user.