Hashing: In Technical Terms

Hashing is a process of converting data (usually of arbitrary size) into a fixed-size string of characters or bytes using a mathematical algorithm called a hash function. The output of a hash function is commonly referred to as a hash value or hash code.

So, why do we use hashing, let's check out some key points about hashing as below

• Deterministic
  Hashing is a deterministic process, meaning that for a given input, the hash function will always produce the same output.
  
  
• Fixed Size Output
  Regardless of the size of the input data, the output of a hash function has a fixed size. For example, the SHA-256 hash function produces a 256-bit (32-byte) hash value.
  
  
• One-Way Function
  Hash functions are designed to be one-way functions, meaning that it should be computationally infeasible to reverse the process and determine the original input from the hash value.
  
  
• Collision Resistance
  A good hash function minimizes the likelihood of producing the same hash value for different inputs. This property is known as collision resistance.
  
  
• Used for Data Integrity and Security
  Hashing is commonly used for data integrity verification, password storage, digital signatures, and various cryptographic applications. By comparing hash values, you can quickly determine if data has been altered or tampered with.
  
  
• Common Hash Functions
  Commonly used hash functions include MD5 (Message Digest Algorithm 5), SHA-1 (Secure Hash Algorithm 1), SHA-256, SHA-512, and more. Newer hash functions like SHA-3 offer enhanced security features.

Here's a simplified example of how hashing works,

Input data (e.g., a file, a password) is passed through a hash function. The hash function processes the input data and produces a fixed-size hash value. The hash value can be stored, transmitted, or used for verification purposes. Even a small change in the input data should result in a significantly different hash value (avalanche effect).

Now, if you feel that Hashing and Encryption are doing same kind of work for you, check out How is hashing different from Encryption below !!

Hashing and encryption are two important concepts in data security that serve different purposes. Hashing is a one-way process of generating a unique digital fingerprint for data to ensure its integrity, whereas encryption is the process of converting plain text into ciphertext to protect confidentiality.

Some of the main differences between hashing and encryption are:

• Hashing is irreversible, meaning that the original data cannot be recovered from the hash value. Encryption is reversible, meaning that the original data can be decrypted with the correct key or password.
• Hashing produces a fixed-length output, regardless of the size of the input. Encryption produces an output that is the same size or larger than the input.
• Hashing does not require a secret key or algorithm to produce a hash value. Encryption requires a secret key or algorithm to encrypt and decrypt data.
• Hashing is used to verify the authenticity and integrity of data, such as passwords, digital signatures, or checksums. Encryption is used to protect the privacy and confidentiality of data, such as messages, files, or emails.
  
  

In summary, hashing is a fundamental concept in computer science and cryptography, providing a mechanism for data integrity verification, security, and various other applications.