Struct Mac 

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

A computed file MAC: 128 uppercase hex characters.

The inner string is private and PartialEq routes through subtle::ConstantTimeEq, so there is no non-constant-time way to compare two of these. Upstream uses Go’s !=; the verdict is identical and the timing channel is gone — a strict improvement that costs nothing at the wire.

Implementations

impl Mac

pub fn as_hex(&self) -> &str

The uppercase-hex rendering, for writing into the file.

A MAC is not a secret — it ships in the file, encrypted only to bind it to the data key — so exposing the string is fine. Comparing it as a plain string is what is prevented, and that is done by making PartialEq the only comparison available.

pub fn from_file(hex: impl Into<String>) -> Self

Adopt a MAC recovered from a file’s decrypted mac field.

pub fn is_absent(&self) -> bool

Whether this MAC is the empty string, which upstream reports as “no MAC” rather than as a mismatch against nothing.

Trait Implementations

impl Clone for Mac

fn clone(&self) -> Mac

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Mac

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

Elided in the middle. A MAC is not secret, but a full 128-char digest in a log line is noise, and printing both ends is what makes a mismatch eyeball-comparable.

impl Eq for Mac

impl PartialEq for Mac

fn eq(&self, other: &Self) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.