Module mimc 

MiMC-Feistel sponge hash function.

MiMC (Minimal Multiplicative Complexity) is a hash function designed for efficient evaluation inside arithmetic circuits, particularly in ZK-SNARKs.

Algorithm

This implementation uses the MiMC-Feistel-Sponge construction with:

• Feistel network structure for the permutation
• Sponge construction for variable-length input
• Exponent of 5 (x^5) for the round function

Constants

The round constants are derived deterministically. The default configuration uses constants compatible with circomlib/Tornado Cash implementations.

References

• MiMC Paper
• circomlib implementation

Example

use stealth_lib::hash::MimcHasher;

let hasher = MimcHasher::default();
let hash = hasher.hash(123, 456);
println!("MiMC hash: {}", hash);

Security Note

This implementation is designed for use in ZK circuits. It is:

• NOT constant-time (do not use where timing attacks are a concern)
• NOT suitable for password hashing (use argon2, bcrypt, or scrypt instead)

Structs

HasherDeprecated

Legacy Hasher struct for backwards compatibility.

MimcHasher

MiMC-Feistel sponge hasher.