Struct Context

pub struct Context { /* private fields */ }

A context for multi-step (Init-Update-Finish) CMAC signing.

Use sign for single-step CMAC signing.

Implementations

impl Context

pub fn with_key(key: &Key) -> Self

Constructs a new CMAC signing context using the given key.

pub fn update(&mut self, data: &[u8]) -> Result<(), Unspecified>

Updates the CMAC with all the data in data. update may be called zero or more times until sign is called.

Errors

error::Unspecified if the CMAC cannot be updated.

pub fn sign(self) -> Result<Tag, Unspecified>

Finalizes the CMAC calculation and returns the CMAC value. sign consumes the context so it cannot be (mis-)used after sign has been called.

It is generally not safe to implement CMAC verification by comparing the return value of sign to a tag. Use verify for verification instead.

Errors

error::Unspecified if the CMAC calculation cannot be finalized.

Panics

Panics if the CMAC tag length exceeds the maximum allowed length, indicating memory corruption.

pub fn verify(self, tag: &[u8]) -> Result<(), Unspecified>

Finalizes the CMAC calculation and verifies whether the resulting value equals the provided tag.

verify consumes the context so it cannot be (mis-)used after verify has been called.

The verification is done in constant time to prevent timing attacks.

Errors

error::Unspecified if the tag does not match or if CMAC calculation fails.

Trait Implementations

impl Clone for Context

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 Context

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

Formats the value using the given formatter.

impl Send for Context