Encryption vs. Hashing: Definitions and Differences

Privacy concerns are rising, and so is the need for robust digital security measures to protect sensitive data. This is where cryptography plays a vital role, particularly through its two key processes: encryption and hashing.

While both are fundamental in keeping digital information secure during data breaches and cyber threats, their processes, use cases, and algorithms differ.

In this guide, we'll review the two methods, including what they are, how they work, and their distinct roles in cybersecurity and data management. We’ll also explore how keys work in encryption and what a hash function is in hashing.

What is encryption?

By definition, encryption is a sophisticated cryptographic technique employed to secure data by converting it from a readable format (aka plaintext) into an encoded version (aka ciphertext). This transformation uses algorithms and encryption keys, which intricately scramble the data, rendering it unintelligible to anyone who doesn’t possess the appropriate decryption key.

Sophisticated encryption algorithms are mathematical instructions that dictate how plaintext is transformed into ciphertext. Their strength is a critical factor in determining the encrypted data’s security.

Encryption keys are secret codes needed to encrypt and decrypt the data. The management and protection of these keys are as important as the strength of the encryption algorithm itself. The two main types of encryption keys used in practice are symmetric and asymmetric.

Symmetric: This uses the same key for encryption and decryption, necessitating a secure method to share the key between parties.
Asymmetric: This is a pair of keys––one public key for encryption and one private key for decryption. This setup enhances security by ensuring that the private key used for decryption is only accessible to the intended recipient.

How does encryption work?

Encryption uses complex algorithms and encryption keys to transform plaintext into ciphertext and securely encode the data. Here's a breakdown of how the process works:

Algorithm selection: The process starts with choosing an encryption algorithm.
Key generation: Next, an encryption key is generated. The nature of the key (its complexity and length) plays a crucial role in determining the encryption’s strength.
Encoding process: The plaintext is processed through the encryption algorithm with the key. The algorithm applies a series of mathematical operations that use the key to change the original data into ciphertext. The resulting ciphertext appears as a random alphanumeric string with no discernible relation to the plaintext.
Transmission: The encrypted data (ciphertext) is safely transmitted or stored. Without the appropriate key, the ciphertext is indecipherable, ensuring the data remains confidential.
Decryption: The same algorithm is used with a corresponding decryption key to convert the ciphertext back to plaintext.

Applications of encryption

Encryption permeates various facets of online interactions and data protection. Here are its few notable use cases:

Secure communications: Encryption helps protect the privacy of digital communications, including emails, messages, and voice calls.
Data security: Encryption ensures data, whether on personal devices or in cloud storage, remains confidential and protected from potential breaches.
Online transactions: In e-commerce and online banking, encryption secures financial transactions, protecting details like credit card numbers and bank account information during transmission over the internet.

Common encryption algorithms

Encryption algorithms are diverse, each designed with specific features to address various security needs and operational environments. From safeguarding personal data to securing state secrets, they form the basis of modern cryptographic security.

Here are a few examples:

Advanced encryption standard (AES)

AES is a symmetric encryption algorithm known for its robustness and speed. It's the gold standard in encryption, used globally for securing sensitive information in government and private sectors. AES operates at different key lengths, typically 128, 192, or 256 bits, with AES-256 being the most secure.

Rivest-Shamir-Adleman (RSA)

Named after its creators Rivest, Shamir, and Adleman, RSA is one of the most widely used asymmetric encryption algorithms. It's fundamental for digital signatures, secure web browsing, and encrypting sensitive data. RSA's security is based on the computational difficulty of factoring large numbers.

Diffie-Hellman Key Exchange

This algorithm enables two parties to securely share a secret key over an insecure medium without any prior knowledge of each other. It's fundamental in establishing secure communications channels.

Triple Data Encryption Standard (3DES)

3DES is an evolution of the original Data Encryption Standard (DES). It applies the DES cipher algorithm three times to each data block, making it more secure than its predecessor. While not as strong as AES, 3DES is still used in security-sensitive applications.

What is hashing?

By definition, hashing is a process used to create a unique, fixed-size string of characters from input data of any size. This process involves a hash function, a mathematical algorithm that takes input data (often called the message) and converts it into a condensed and seemingly random output (aka hash value or hash).

Key characteristics of hashing include:

Deterministic: The same input always produces the same hash value, making it possible to verify data integrity by comparing hash values.
Fixed-size: Regardless of the input data’s size or length, the hash function generates a fixed-length value. This uniformity is crucial for data storage and comparison efficiency.
Fast computation: Hash functions are quick and efficient, enabling rapid processing of large data volumes.
Preimage resistance: It should be computationally infeasible to reverse-engineer or deduce the original input data from its hash value. This one-way nature is a critical security feature.
Small changes lead to big differences: Even a tiny change in the input data (like altering a single character) will result in a significantly different hash value. This property, called the avalanche effect, is essential for detecting any alterations in the data.
Collision resistance: A good hash function minimizes the probability of different inputs producing the same hash value (aka a collision).

How does hashing work?

Hashing transforms input data into a fixed-size string of alphanumeric characters. Here's an overview of how hashing works:

Transforming the data: Hashing starts with any form of data––such as a text file, a digital image, or any other file type––which can vary in size and complexity.
Applying the hash function: The input data is then processed through a hash function.
Generating the hash value: After processing the data through the hash function, the output is a hash value.
Using the hash value: The resulting hash value is used in various applications. For example, in data integrity checks, the hash value serves as a digital data fingerprint. If the data changes, its hash value also changes, indicating potential tampering.

Hashing use cases

Hashing has applications in various aspects of digital security and data management. Here are a few common use cases:

Blockchain and cryptocurrencies: Hash functions are a core component of blockchain technology. They create a unique identifier for each block and proof-of-work (PoW) in cryptocurrency mining processes.
Password storage: Instead of actual passwords, systems store their hash values. When a user logs in, the system hashes the entered password and compares it with the stored hash value, adding a layer of security against password theft.
Data integrity verification: Hashing is used to verify data’s integrity. By comparing the hash value of the received data with the expected hash, one can determine if the data has been altered or corrupted during transmission.

Common hashing algorithms

Over the years, several hashing algorithms have become standards due to their reliability and robustness. Here are a few common ones:

Message-Digest Algorithm 5 (MD5)

MD5 produces a 128-bit hash value. It was designed for fast processing but is now considered vulnerable due to weaknesses that allow for hash collisions (two different inputs producing the same hash).

Secure Hash Algorithm (SHA)

This family of algorithms, developed by the National Security Agency (NSA), includes several versions like SHA-1, SHA-256, and SHA-3. Each version differs in terms of the hash size it produces and its security level.

BLAKE3

BLAKE3 is an evolution of the BLAKE2 hash function known for its exceptional speed and security. It's a cryptographic hash function that’s efficient in software and hardware implementations and offers a high degree of resistance against cryptographic attacks.

How is hashing different from encryption?

Hashing and encryption are both fundamental cryptographic techniques used in securing data, but they serve different purposes and operate in distinct ways:

Purpose

While encryption protects data confidentiality by encoding information so only authorized parties can access the original data, hashing verifies data integrity or is used for indexing.

Process

Encryption transforms data using algorithms and keys. With the correct key, users can decrypt the encrypted data back to its original form. Hashing, however, transforms data into a string of a fixed length, regardless of the input data’s size. The same input always produces the same hash, but users can’t retrieve the original data from the hash.

Output

Encryption’s output (ciphertext) can vary in length, depending on the plaintext and the method used. Hashing’s output, conversely, is always of a fixed length, no matter the input data’s size.

Use cases

Encryption secures sensitive data in transit or at rest, such as in secure communications or storing confidential files. Hashing, however, stores passwords securely, verifies data integrity, and creates a unique digital fingerprint of transactions in blockchain technology.

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