Arthur Levitt, a former chairman of the Securities and Exchange Commission, has been named an adviser to two bitcoin companies.

Levitt has begun working with BitPay, a bitcoin processor, and Vaurum, a bitcoin exchange, on issues ranging from marketing to business monitoring.

"Bitcoin is a fascinating new product in the rapidly changing world of financial service," Levitt said in a press release Tuesday. "I hope to help BitPay and Vaurum blend their new business models with core monetary methods and transparency practices to ensure their long-term success."

His appointment comes as the industry faces increasing pressure from federal and state regulators, who have criticized the currency for having volatile exchange rates and high transaction fees.

The Consumer Financial Protection Bureau issued a warning on bitcoin in August, saying that it poses dangers to consumers. It has also begun accepting complaints on virtual currencies, often one of the first steps toward future regulations.

"Virtual currencies are not backed by any government or central bank, and at this point consumers are stepping into the Wild West when they engage in the market," CFPB Director Richard Cordray said in an Aug. 11 press release.

Additionally, New York banking regulator Benjamin Lawsky has proposed a regulatory framework that would require bitcoin companies to hold higher capital levels and hire compliance officers.

Levitt, the longest-serving SEC chairman, led the agency during the Clinton administration, from 1993 until 2001.