7. Is there a ban on anonymous donations to political parties?

Art 124.5 '5. The donations of natural or legal persons, including the contributions of the candidates, are documented in writing signed by the donor and the electoral administrator. In the case of gifts in kind, the supporting document must discriminate completely their number or quantity, their object and the value attributed to it, which can not be lower than its market value.' (Source Codigo Eleitoral 2010) 

Not directly a ban but implied