WeWork is the latest in a string of popular companies to announce plans to incorporate cryptocurrencies in their businesses.
Visa Inc said last month it would allow payment settlements using cryptocurrency while PayPal Holdings Inc launched a crypto checkout service on March 30.
The decision could stall Turkey's crypto market, which has gained momentum in recent months as investors joined the global rally in bitcoin, seeking to hedge against lira depreciation and inflation that topped 16% last month.
In a statement, the central bank said crypto assets were "neither subject to any regulation and supervision mechanisms nor a central regulatory authority", among other security risks.
If necessary, the central bank will launch a pilot programme that involves payment service providers and end users, BOJ Executive Director Shinichi Uchida said last month.
BNY Mellon's investment was part of a $133 million funding round that also saw participation from hedge fund Coatue Management, investment firm Ribbit Capital, growth equity firm Stripes and SVB Capital.
Fireblocks has a presence in Europe, Asia and North America, with customers including banks, neobanks, exchanges, hedge funds and market makers.
The Securities and Exchange Commission (SEC) has meanwhile sought to regulate cryptocurrency investments on the grounds that they qualify as securities transactions.
The central bank has argued that cryptocurrencies, which are unregulated and not legal tender, are risky for the user.
Central banks from the Group of Seven nations set out in October how a digital currency could function, though progress has been slow.
Access to central bank money beyond physical cash has so far been restricted to financial institutions. Extending it to the broader public would have major economic and financial repercussions.
The North is also blamed for a huge, $81 million cyber-heist from the Bangladesh Central Bank, as well as the theft of $60 million from Taiwan's Far Eastern International Bank.
The law will "create a facilitative framework for creation of the official digital currency to be issued by the Reserve Bank of India (RBI)."
The RBI had in April 2018 ordered financial institutions to break off all ties with individuals or businesses dealing in virtual currency such as bitcoin within three months.
He added that the bulk of investors are not day-to-day traders, but people making a long-term punt -- and he estimates that the spectacular price boom of recent weeks has involved only around five millions units.
Lagarde did not provide specific examples of money laundering cases but said she understood there had been criminal investigations into illegal activity. She did not elaborate.
Bitcoin fell as far as $33,447, its lowest since Jan. 6. Ethereum which often moves in tandem with bitcoin, fell as much as 20% to a one-week low of $1,007.51.
"Respectively, these same funds will no longer be available for lending, which will eventually lead to a liquidity deficit and as a consequence, rising rates," he said.