Struct ring::hmac::Key

pub struct Key { /* private fields */ }

A key to use for HMAC signing.

Implementations

impl Key

pub fn generate( algorithm: Algorithm, rng: &dyn SecureRandom ) -> Result<Self, Unspecified>

Generate an HMAC signing key using the given digest algorithm with a random value generated from rng.

The key will be digest_alg.output_len bytes long, based on the recommendation in RFC 2104 Section 3.

pub fn new(algorithm: Algorithm, key_value: &[u8]) -> Self

Construct an HMAC signing key using the given digest algorithm and key value.

key_value should be a value generated using a secure random number generator (e.g. the key_value output by SealingKey::generate_serializable()) or derived from a random key by a key derivation function (e.g. ring::hkdf). In particular, key_value shouldn’t be a password.

As specified in RFC 2104, if key_value is shorter than the digest algorithm’s block length (as returned by digest::Algorithm::block_len(), not the digest length returned by digest::Algorithm::output_len()) then it will be padded with zeros. Similarly, if it is longer than the block length then it will be compressed using the digest algorithm.

You should not use keys larger than the digest_alg.block_len because the truncation described above reduces their strength to only digest_alg.output_len * 8 bits. Support for such keys is likely to be removed in a future version of ring.

pub fn algorithm(&self) -> Algorithm

The digest algorithm for the key.

Trait Implementations

impl Clone for Key

fn clone(&self) -> Key

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for Key

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

Formats the value using the given formatter.

impl From<Okm<'_, Algorithm>> for Key

fn from(okm: Okm<'_, Algorithm>) -> Self

Converts to this type from the input type.