Module metadata 

Plaintext layout of the encrypted metadata envelope. Plaintext layout of the encrypted metadata envelope.

The envelope is serialized, then AEAD-encrypted under the metadata domain and stored in the header. Layout (little endian):

field	size	present
flags	1 byte	always
filename_len	2 bytes	always
filename	variable	always (UTF-8)
mtime_secs	8 bytes	flags bit 0 (signed)
mtime_nanos	4 bytes	flags bit 0
mode	4 bytes	flags bit 1

Flags bit 2 marks the content as a crate::archive stream (a directory tree) instead of a single file’s bytes; filename is then the directory name.

Trailing unknown bytes are rejected: this layout is fixed for the v3 format, and any extension is a new format version.

Functions

parse

Parses a decrypted metadata envelope. Any structural mismatch (bad lengths, unknown flags, trailing bytes, invalid UTF-8 filename) is FileError::InvalidMetadata.

serialize

Serializes a metadata envelope. Fails with HeaderError::MetadataTooLong when the filename pushes the envelope past what the header can hold.