Argon2i is the data-independent variant of Argon2 where memory access patterns are predetermined, providing resistance to side-channel attacks at the cost of some GPU resistance, making it suitable for password hashing in shared environments.
Specifications
Output SizeVariable
StandardRFC 9106
Standard Year2021
Origin Password Hashing Competition (PHC Winner)
Origin Year 2015
Use Cases
—Password hashing in shared environments
—Side-channel attack resistance required
—Cloud password storage
—Virtualized environments
—Where timing attack resistance is critical
Security Notice
Argon2i has lower GPU resistance than Argon2d. Argon2id provides the best balance for most password hashing scenarios.
Frequently Asked Questions
Argon2i uses data-independent memory access, making it resistant to side-channel attacks. Use it in shared/cloud environments where timing attacks are a concern. However, Argon2id is generally preferred as it provides similar side-channel resistance with better GPU resistance.
Yes. Argon2i's data-independent memory access makes it somewhat easier for GPUs to compute in parallel compared to Argon2id. The difference isn't huge, but Argon2id is generally preferred for providing the best balance of protections.
Yes, Argon2i is suitable for cloud environments where side-channel attacks from co-tenants are a concern. However, Argon2id provides similar side-channel protection with better overall security and is the recommended default for most password hashing scenarios.