Struct StretchedMaster 

pub struct StretchedMaster { /* private fields */ }

A high-entropy 32-byte master for ALL of a user’s key derivations — the per-audience AEAD keys AND the X25519/Ed25519 identities derive from THIS (via HKDF), never from a raw passphrase. The type is the gate: an identity or audience key cannot be derived from an unstretched password, because those functions take &StretchedMaster, and the only ways to build one are the two constructors below.

Implementations

impl StretchedMaster

pub fn from_passphrase(passphrase: &[u8], user_id: &str) -> Self

Argon2id-stretch a (password-equivalent) passphrase into the master, deterministically per user (see [argon2_salt]).

SECURITY — mitigation, NOT closure: this raises the per-guess cost of a weak passphrase but cannot mint entropy it never had. The user’s identity PUBLIC key is published (the platform maps account_id → pubkey), which is an OFFLINE verification oracle — an attacker guesses a passphrase, stretches, derives, and compares to the published key with NO network. Argon2id’s per-guess cost is then the entire wall; a short password still falls. A PAKE removes the oracle and is the strictly stronger path. Passphrase policy, param benchmarking, and the PAKE alternative still require a cryptographer before production.

pub fn from_issued_high_entropy(secret: &[u8], user_id: &str) -> Self

From a Parslee-issued high-entropy secret (the caller CERTIFIES it is ≥256-bit). Skips Argon2id — stretching a strong key is pointless cost — and HKDF-binds it to user_id for per-user domain separation.

pub fn profile(&self) -> KdfProfile

The profile that minted this master (for the rotation/migration machinery).

Trait Implementations

impl Debug for StretchedMaster

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.