# The security of Hidden Field Equations - sentence

I am reading this paper "The security of Hidden Field Equations (HFE)"
and at the end of the page 3 the author wrote:

The random oracle paradigm would be to ignore that the function formulae exist.

I know what is the random oracle paradigm but sincerily I do not understand why the
"The random oracle paradigm would be to ignore that the function formulae exist."
Could you explain me please what that sentence means?

In the paragraphs before the sentence you highlighted, they propose to measure the "complexity" of an equation / function by the degree of its multivariate polynomial representation over $GF(2)$.