Argon2 Password Hashing

About Argon2

Argon2 is a key derivation function that was selected as the winner of the Password Hashing Competition in July 2015. It was designed by Alex Biryukov, Daniel Dinu, and Dmitry Khovratovich from the University of Luxembourg.

Key Features:

Memory-Hard: Designed to use a large amount of memory, making it resistant to attacks using specialized hardware like GPUs and ASICs
Tunable Parameters: Allows adjusting memory usage, computation time, and parallelism to suit different security requirements
Multiple Variants: Comes in three variants (Argon2d, Argon2i, Argon2id) with different security properties
Modern Design: Incorporates lessons learned from previous password hashing functions
Salt Support: Uses random salts to prevent precomputed table attacks

Advantages:

Stronger security against hardware-based attacks compared to older algorithms
Highly configurable to balance security and performance
Winner of the Password Hashing Competition
Recommended by security experts and organizations like OWASP
Suitable for a wide range of applications from web services to high-security systems

Recommended Parameters:

Use Case	Variant	Memory Cost	Time Cost	Parallelism
Web Applications	Argon2id	32 MB	2	2
High Security	Argon2id	64-128 MB	3-4	4
Resource Constrained	Argon2id	16 MB	1	1

Security Best Practice: Argon2id is currently recommended as the best choice for password hashing. It provides a good balance between resistance to side-channel attacks and GPU/ASIC attacks.

Generate Argon2 Hash

Password:

Argon2 Variant:

Argon2id is the recommended variant for most use cases.

Memory Cost (KiB):

Time Cost (Iterations):

Parallelism:

Verify Password

How Argon2 Works

Argon2 is a memory-hard password hashing function that uses a sophisticated approach to resist various attacks.

Core Operation:

Initialize memory blocks with the password, salt, and other parameters
Perform multiple passes over the memory to create dependencies between blocks
Extract the final hash value from the memory state

Variant Differences:

Argon2d: Data-dependent memory access pattern - faster but vulnerable to side-channel attacks
Argon2i: Data-independent memory access pattern - more resistant to side-channel attacks
Argon2id: Hybrid approach - first half uses Argon2i, second half uses Argon2d

Comparison with Other Password Hashing Functions:

Algorithm	Advantages	Disadvantages
Argon2	Modern design with strong security Memory-hard (resistant to hardware attacks) Highly tunable parameters	Newer, less battle-tested More complex to implement correctly
Bcrypt	Well-established and widely used Simple to use with good library support	Limited memory hardness Fixed memory usage (128 KB)
PBKDF2	Widely supported in many platforms NIST approved	Not memory-hard Vulnerable to GPU/ASIC attacks

Note: This is a simplified explanation. The actual implementation involves complex mathematical operations and careful parameter selection to ensure security.