\section{Motivation}\label{motivation}
To be able to donate to a charity and deduct that donation from taxes, it is
often required to provide evidence. The donor would have to present said
evidence in form of a donation receipt which would include information about
both the donor and the charity. The donor may want to keep this information
private and only provide a receipt that proves that a certain amount was indeed
donated to a recognized charity.

%privacy
There are many reasons why such information can be sensitive and should be
hidden from third parties. Both personally and politically this information
could be harmful to individuals if not handled responsibly. To remain
anonymous donors would have to keep their donation receipts, which would not
allow them to deduct the donation from taxes. It is best to reduce and
anonymize this information as much as possible, while still having all the
necessary information to verify donations and prevent illegal practices.

%simplicity
Tax authorities may have to verify donations manually which can be time
consuming and involves a disproportionate amount of effort for the tax
authority. The donor on the other hand has to keep track of the donation
receipts. It is not unheard of, that these receipts get lost or forgotten by
the time the tax declaration is submitted.

%standardisation
For every donation the donor wants the donation to be tax deductible, the
addressed charity has to be recognized by the local tax authority. However, it
can happen that donations to unrecognized charities are mistakenly deducted or
that donations to recognized charities abroad are not deducted. This misconduct
has found attention by Michiel Leenaars from the NLnet Foundation\footnote{see
\url{https://nlnet.nl/}}. He has noticed that donations to their organization
from other countries are sometimes not deducted from the taxes of their donors,
although this should be the case in the European Union according to the article
63 of \cite{eulaw}.

