Argon2 is a password-hashing function designed to be secure against various attacks, including side-channel attacks, and to offer resistance to both time-memory tradeoff (TMTO) and GPU-based attacks. Here's detailed information about Argon2:
History and Context
- Argon2 was developed by Alex Biryukov, Daniel Dinu, and Dmitry Khovratovich as a result of the Password Hashing Competition (PHC) in 2015.
- It was designed to succeed the earlier winners of the PHC, bcrypt and scrypt, by addressing their limitations and providing a more robust solution against modern attack vectors.
Key Features
- Memory Hardness: Argon2 requires a significant amount of memory, making it resistant to hardware-based attacks like those using GPUs or ASICs, which typically have less memory available.
- Time-Memory Tradeoff Resistance: It's designed to resist attacks where attackers try to reduce the memory usage by increasing the time taken to compute the hash.
- Multiple Variants:
- Argon2d: Optimized for scenarios where side-channel attacks are a concern due to its data-dependent memory access.
- Argon2i: Provides protection against side-channel attacks through its data-independent memory access.
- Argon2id: A hybrid version that combines the benefits of Argon2i and Argon2d, offering a balance between security against side-channel attacks and resistance to TMTO attacks.
- Adjustable Parameters: Users can tune parameters like memory size, parallelism, and the number of iterations to balance security and performance needs.
Usage
- Argon2 is used in various applications for securely hashing passwords, key derivation, and in systems where security against modern computational attacks is paramount.
- It has been adopted by several standards bodies and is recommended for use in cryptographic protocols.
Security Considerations
- While Argon2 is considered one of the most secure password hashing functions available, its implementation must be done correctly to avoid vulnerabilities. Misuse of parameters or incorrect implementation can reduce its effectiveness.
- The function's security depends on the correct choice of parameters, which should be adjusted based on the hardware capabilities and the desired security level.
References
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