Module crypto 

Low-level cryptography primitives for tsafe.

Key derivation: Argon2id with tunable cost parameters. Encryption: XChaCha20-Poly1305 by default, with optional AES-256-GCM support behind the fips feature flag. All secret material is handled via Zeroizing wrappers so keys are wiped from heap memory on drop.

Structs

VaultKey

A 256-bit key that is zeroed from memory on drop.

Enums

CipherKind

Cipher selection for vault/team ciphertext on disk.

KeyPurpose

Purpose labels for HKDF expansion. Adding new purposes must use a distinct label so old ciphertext domains remain isolated.

KeySchedule

The on-disk vault format historically used the root key directly. Newer vaults keep the same file format but scope encryption through HKDF-derived purpose keys so challenge/data material do not share a key.

Constants

KEY_LEN

NONCE_LEN

SALT_LEN

VAULT_KDF_M_COST

VAULT_KDF_P_COST

VAULT_KDF_T_COST

XCHACHA20POLY1305_NONCE_LEN

Functions

decode_b64

decrypt

Decrypt with XChaCha20-Poly1305. Authentication failure returns DecryptionFailed.

decrypt_for_cipher

decrypt_with_key_schedule

default_vault_cipher

derive_key

Derive a 256-bit key from a password + salt using Argon2id.

derive_labeled_subkey

Derive a 256-bit subkey from a root key using an explicit HKDF label.

derive_subkey

Derive a purpose-scoped 256-bit subkey from a root key using HKDF-SHA256.

detect_key_schedule

Detect which key schedule was used for a known-plaintext record.

encode_b64

encrypt

Encrypt plaintext with XChaCha20-Poly1305. Returns (nonce, ciphertext).

encrypt_for_cipher

encrypt_with_key_schedule

parse_cipher_kind

random_nonce

random_salt

snap_decrypt

Decrypt a snap blob received from the snap server.

snap_encrypt

Encrypt a plaintext string for one-time snap sharing.