Citigroup Inc.'s Global Transaction Services unit said it has successfully completed cross-certification of an identity authorization process for outside entities working with the federal government.

Citi worked with CertiPath LLC, a company that certifies identity authorization procedures for the government, specifically for contractors and subcontractors, primarily the Department of Defense.

"Digital identity over time will be a convergence of payment and digital identity cards," said Gary Schneider, managing director of public-sector product management with Global Transaction Services.

Citi currently enables identity authorization for its large pharmaceutical clients, whose scientists are required by the Food and Drug Administration to validate who they are for drug trials. It does not use a Personal Identity Verification authorization standard, or PIV-I, in such cases.

Citi will now use PIV-I to authenticate federal guest workers and first responders to national disasters, such as fire department and other emergency workers, using CertiPath's identity bridge. There are more than 25 million first responders who might require identification, the New York banking company said in a press release Monday.

Schneider said that Citi could also add a payroll capability to the cards that identify guest workers.

CertiPath, of Herndon, Va., said it foresaw three areas in which Citi could use the cards: identification authorization online, access to physical locations and, ultimately, authentication of people involved in money movement.

"This is step one to seeing a harmonization between identity and EMV chip," a chip commonly used in payment cards in other countries, Steve Howard, vice president of credentials for CertiPath, said in an interview.

The goal is to make the authorization interoperable, experts said, so that ultimately identification can work in many different environments, both inside and outside government, as well as across industries.

"Generally speaking, banks have always supported [public key infrastructure] for authorization and encryption," said Avivah Litan, vice president and distinguished analyst at Gartner Inc. "This will be interesting when it is federated" and banks can share identity cards.