Struct Policy 

pub struct Policy<'a> {
    pub identifier: Oid<'a>,
    pub algorithm: AlgorithmIdentifier<'a>,
    pub hash: Octets<'a>,
    pub hash_unknown: bool,
}

Original signature-policy identifier and declared document digest. The signature-policy document’s technical specification determines the hashing input; an all-zero digest means UNKNOWN, never the empty document’s digest.

Fields

identifier: Oid<'a>

Original signature policy OID.

algorithm: AlgorithmIdentifier<'a>

Original written digest mechanism and parameter provenance.

hash: Octets<'a>

Original declared digest, including constructed BER fragments.

hash_unknown: bool

Normative zero-hash marker, independent of output width (§5.2.9.1).