ASN.1 type DigestAlgorithmIdentifier is defined as follows:

    DigestAlgorithmIdentifier ::= SEQUENCE {
       algorithm   ALGORITHM.&id({DigestAlgorithms}),
       parameters  ALGORITHM.&Type({DigestAlgorithms}{@algorithm})  OPTIONAL
    }

    DigestAlgorithms ALGORITHM ::= {

       ... -- Expect additional digest algorithm objects  --
    }
    
    ALGORITHM ::= CLASS {
       &id    OBJECT IDENTIFIER  UNIQUE,
       &Type  OPTIONAL
    }
      WITH SYNTAX { OID &id [ PARMS &Type ] }