Cryptocurrency is bumping up against centuries-old legal doctrines on abandoned property, presenting new concerns about who actually holds these digital assets and how states are able to claim them.

States are seeking to apply escheatment laws — which date back to feudal England — to present-day cryptocurrencies such as bitcoin, ethereum, bitFlyer and zcash. That’s even as the technological issues remain unresolved.

While all 50 states have escheatment laws on the books, few have explicitly amended their unclaimed-property statutes to cover cryptocurrencies. That, however, could soon be changing as states seek to tap a potentially lucrative source of revenue.

New York is among the latest to consider legislation calling for unclaimed cryptocurrency to be transferred to the state after the digital assets have been abandoned. A bill pending in the state Assembly would liquidate such assets and turn them over to a state office.

A handful of other states, including Illinois, Colorado, Tennessee and Utah, have already adopted a definition of virtual currency as property, International law firm Greenberg Traurig LLP reported in a recent legal analysis.