Function read_implicit 

pub fn read_implicit<'a>(
    parent: &Reader<'a>,
    element: &Element<'a>,
    number: u32,
    field: &'static str,
) -> Result<AlgorithmIdentifier<'a>>

Reads an original [number] IMPLICIT AlgorithmIdentifier without retagging.

The caller supplies the tag number selected by its trusted schema. For example, CMSAlgorithmProtection uses [1] for a signature and [2] for a MAC (RFC6211 §2); that cardinality/choice rule belongs to the CMS schema. The same inner algorithm/parameter core as read preserves original bytes, encoding, inherited depth and current producing execution ceilings. https://www.rfc-editor.org/rfc/rfc6211#section-2