Anyone who offers goods and services for sale in the market is qualified to issue currency. THE END OF MONEY AND THE FUTURE OF CIVILIZATION, by Thomas H. Greco, Jr., 2009
Most of the ethereum ERC20: Token standard tokens rely only on promises just stated at a website.
A Ricardian contract is a document which is legible to both a court of law and to a software application. Its purpose is to provide digital trading systems of various kinds the solidity of legally binding claims on property, so that you and your partners can concentrate on the business opportunity. The Ricardian Contracthttp://iang.org/ricardian/
Swarm protocol allows to bind any ethereum ERC20: Token to a human readable and legal valid document through it swarm hash. Semantics, Blockchains and Ricardian Contracts https://www.slideshare.net/christopherbrewster/semantics-blockchains-and-ricardian-contracts