Struct CacheKey 

pub struct CacheKey(/* private fields */);

Secret key signing every cache entry with HMAC-SHA256, so an entry written without the key (a committed or planted file) is never trusted.

Implementations

impl CacheKey

pub fn from_bytes(bytes: [u8; 32]) -> Self

Wrap raw key bytes.

pub fn load_or_create(dir: &Path) -> Result<Self, CacheError>

Load the key stored in <dir>/cache.key, creating it (random bytes, mode 0600 on unix) when missing. A key file of the wrong length is replaced, which invalidates every entry signed with the old one.

Errors

Returns CacheError::InvalidKey when the key path is not a regular file (a symlink is never followed), and CacheError::Io when the key cannot be read, generated or written.

pub fn load_or_create_default() -> Result<Self, CacheError>

CacheKey::load_or_create in user_cache_dir.

Errors

Same as CacheKey::load_or_create.

pub fn seal(&self, name: &str, payload: &[u8]) -> Result<Vec<u8>, CacheError>

Sign payload for the entry called name: the 32-byte HMAC-SHA256 tag followed by the payload. Binding the name stops a validly signed entry from being moved onto another key.

Errors

Returns CacheError::Io if the HMAC cannot be initialized.

pub fn open<'a>(&self, name: &str, data: &'a [u8]) -> Option<&'a [u8]>

Verify data produced by CacheKey::seal for the entry called name and return its payload. A missing, truncated or invalid tag (compared in constant time) yields None, so the caller recomputes the entry.

Trait Implementations

impl Clone for CacheKey

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for CacheKey

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

Formats the value using the given formatter.