New returns digest authentication strategy.

SetHash set the hashing algorithm to hash the user password.

SetOpaque set digest opaque.

SetRealm set digest authentication realm.

ErrInavlidHeader is returned by Header parse when authz header is not digest.

ErrInvalidResponse is returned by Strategy when client authz response does not match server hash.

Digest authentication strategy.

FetchUser a callback function to return the user password and user info.

Header represents The Authorization Header Field, and WWW-Authenticate Response Header Field as described in RFC 7616.