"I am deeply troubled by the Department of Justice's hyper-aggressive argument that non-custodial software can constitute a money transmission service," said Senator Cynthia Lummis in a statement.

"This stance contradicts existing Treasury guidance, common sense and violates the rule of law. Arguments against self- custody software threaten the fundamental property rights that are core to being an American."

"I will do everything I can to fight for your rights to hold your own keys and run your own node," she added.