The Internal Revenue Service has proposed modifying how a taxpayer’s Social Security Number is displayed on the Form W-2 in an effort to further head off identity theft.

The proposal would allow employers to voluntarily truncate the employee’s SSN on the taxpayer’s copy of the W-2. The shortened SSN would appear in the form of an IRS Truncated Taxpayer Identification Number (TTIN).

If enacted, the change would also amend section 6109 regulations, clarifying the application of truncation rules to Forms W-2.

The 20-page proposal from the Treasury Department includes an example of how the truncation might work. A TTIN replacing an SSN would appear as XXX-XX-1234 or ***-**-1234 on the W-2. Copies of the W-2 going to the IRS would still carry the full SSN.

The remaining language in the new regulations aims to clean up a portion of the tax code a bit by deleting some obsolete tax provisions and updating some cross-references in the remaining regulations.

Comments on the proposed regulations are being taken by the IRS until Dec. 18.