The Internal Revenue Service has restored its “Get an IP PIN” tool to the IRS.gov website, after concerns about security forced its removal.

The Identity Protection Personal Identification Number (IP PIN) is issued to taxpayers who are confirmed to be victims of identity theft and certain taxpayers who opt into the program. The six-digit IP PIN attempts to add an additional protection for the taxpayer’s Social Security Number.

This new version of the tool uses a multi-factor authentication process, aimed at preventing automated attacks.

The new Secure Access process requires taxpayers to have immediate access to an email address, account information from a credit card or some other type of loan, and a text-enabled cell phone. The new security measures apply for new and returning users of the IP PIN tool.

Use of the IP PIN tool is limited to pre-selected taxpayers. Some 2.7 million IP PIN holders will receive their number through the mail late in the calendar year in advance of the 2017 filing season. Taxpayers who lose their IP PIN may use the tool to retrieve their number. Taxpayers who may be victims of non-tax-related identity theft and who submitted an affidavit to the IRS may also opt into the program and obtain an IP PIN through the tool. Taxpayers from Florida, Georgia and the District of Columbia can also get an IP PIN through the tool as part of a pilot project.

The new version of the online IP PIN tool uses the same Secure Access process that debuted with the revamped Get Transcript Online tool. The transcript tool was shut down after hackers used stolen personal information to get around existing security measures. The new process is designed to make that kind of attack much more difficult. Get Transcript Online has also been returned to service.

The IRS says it is continuing to review its other online application to determine which ones would best be served with the new verification process.