The development of digital technology has given rise to innovations such as
cryptocurrency, with Bitcoin being one of the most prominent. Its growing use as
an investment instrument has led to new legal questions, particularly concerning
its potential use as an object of property security in Indonesia. This study aims to
analyze the legal relationship between Bitcoin buyers and sellers and to examine
whether Bitcoin can be used as collateral under Indonesian law. This research
employs a normative legal method with statutory and conceptual approaches. The
results show that the legal relationship between Bitcoin buyers and sellers
constitutes a civil relationship arising from a sale and purchase agreement as
regulated in the Indonesian Civil Code (KUHPerdata). Furthermore, Bitcoin can
be legally categorized as an intangible movable asset that has economic value and
can be transferred, thus fulfilling the requirements to serve as an object of property security through fiduciary guarantees under Law No. 42 of 1999 concerning Fiduciary Security. However, the high volatility of Bitcoin’s value and the absence of specific regulations governing digital asset guarantees have led to legal uncertainty in practice. Therefore, clearer and more comprehensive regulations are necessary to ensure legal certainty and protection for parties involved in digital asset–based security transactions.