Gehasis

Gehasis refers to a group of cryptographic techniques designed to securely store and retrieve data using a password or passphrase. The term is often associated with password-based key derivation functions (PBKDFs) and other methods that enhance the security of stored credentials or encryption keys. These techniques are widely used in computer security to protect sensitive information, such as passwords, encryption keys, and other confidential data, against unauthorized access.

The primary purpose of gehasis is to slow down brute-force attacks by requiring significant computational effort to derive the correct key from a password. This is achieved through iterative hashing, salting, and other cryptographic enhancements. Salting involves adding a random value to the password before hashing, ensuring that even identical passwords produce different hash outputs, which prevents attacks that rely on precomputed hash tables (rainbow tables).

Common gehasis methods include:

- **PBKDF2 (Password-Based Key Derivation Function 2)**, which applies a pseudorandom function (such as HMAC) to the input password iteratively.

- **bcrypt**, a function designed to be slow by default, making it resistant to brute-force attacks.

- **Argon2**, a modern key derivation function selected as the winner of the Password Hashing Competition (PHC) in 2015, known for its memory-hard properties.

- **scrypt**, another memory-hard function that combines computational and memory-intensive operations.

Gehasis is widely implemented in systems requiring secure password storage, such as authentication databases, encrypted filesystems, and secure communication protocols. By combining strong hashing algorithms with proper salting and key stretching, gehasis significantly improves security against common attack vectors while maintaining usability for legitimate users.