Struct FileHeader 

pub struct FileHeader {
    salt: [u8; 16],
    kdf_params: KeyDerivationParams,
    nonce_prefix: [u8; 16],
    chunk_size: u32,
    metadata_nonce: [u8; 24],
    metadata_ciphertext: Vec<u8>,
}

Complete v3 file header.

Differences from v2: the content is encrypted as a sequence of AEAD chunks (see crate::v3::stream) using a 16-byte nonce prefix stored here, and the bare filename ciphertext is replaced by an encrypted metadata envelope carrying the filename plus optional mtime and Unix mode. All fixed fields are authenticated as associated data via HeaderBinding, with distinct domains for metadata and content.

The struct holds only the header’s actual information content; the layout artifacts of the serialized form (magic, version byte, length fields) are computed during (de)serialization and never stored.

Serialized layout:

field	size
magic (“SHADOW”)	6 bytes
version (3)	1 byte
header_length	4 bytes
salt	16 bytes
kdf_memory	4 bytes
kdf_iterations	4 bytes
kdf_parallelism	4 bytes
kdf_key_length	1 byte
nonce_prefix	16 bytes
chunk_size	4 bytes
metadata_nonce	24 bytes
metadata_ciphertext_length	2 bytes
metadata_ciphertext	variable

Fields

salt: [u8; 16]

kdf_params: KeyDerivationParams

nonce_prefix: [u8; 16]

chunk_size: u32

metadata_nonce: [u8; 24]

metadata_ciphertext: Vec<u8>

Implementations

impl FileHeader

pub fn new( salt: [u8; 16], kdf_params: KeyDerivationParams, nonce_prefix: [u8; 16], chunk_size: u32, metadata_nonce: [u8; 24], metadata_ciphertext: Vec<u8>, ) -> Result<FileHeader, HeaderError>

Builds a v3 header. Fails with HeaderError::MetadataTooLong if the metadata ciphertext does not fit the u16 length field, and with HeaderError::InvalidData for a chunk size outside 1..=MAX_ACCEPTED_CHUNK_SIZE.

pub fn header_length(&self) -> usize

Total length of this header’s serialized form.

pub fn serialize(&self) -> Vec<u8>

pub fn try_deserialize(bytes: &[u8]) -> Result<FileHeader, HeaderError>

pub fn salt(&self) -> &[u8; 16]

pub fn kdf_params(&self) -> &KeyDerivationParams

The key derivation parameters recorded in this header.

pub fn nonce_prefix(&self) -> &[u8; 16]

pub fn chunk_size(&self) -> u32

pub fn metadata_nonce(&self) -> &[u8; 24]

pub fn metadata_ciphertext(&self) -> &[u8]

pub fn decrypt_metadata( &self, key: &SecureKey, ) -> Result<FileMetadata, FileError>

Decrypts and parses the metadata envelope stored in this header, verifying the header binding under the metadata domain.

pub fn binding(&self) -> HeaderBinding<'_>

The header binding used as associated data for this header’s AEAD operations.

Trait Implementations

impl Clone for FileHeader

fn clone(&self) -> FileHeader

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for FileHeader

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

Formats the value using the given formatter.