In an effort to snip the budding fake identification industry, the state Registry of Motor Vehicles plans to add extra safeguards designed to prevent those under 21 years old from using altered licenses to buy liquor.

State officials said they will move the birthdate to the middle of every license, making it more difficult to tamper with it. In addition they plan to print "Under 21" in bold red type on minors' licenses.

"This is so a young person can't tamper with it and buy liquor," said Vincent Coporchio of the registry.

But Registry officials said that no license is tamper-proof. "As soon as you make a tamper-proof license someone figures out how to tamper with it," Kathi Connelly, a spokesman, said.

Cambridge liquor store owners welcomed the change. "It's going to be easier to identify fakes right away," said Gary Locke, the manager of the Harvard Provision Company. Locke said his store "is very tough" on fake identification cards and can recognize most fakes.

"I don't know that it is a particular problem in Cambridge," said Sgt. Richard Bongiorno, of the Cambridge police. He added that there are no special enforcement operations taken by the police to catch tamperers. "But if people are caught with a tampered license it's a felony."

Registry officials said they had to take the new measures for the licenses in order to maintain the credibility of motor vehicle operators licenses, which, they say, have become the common form of identification.

Police recently arrested a 21-year-old Boston man for making counterfeit licenses and selling them for up to $60 apiece. He pleaded no contest in Brookline District Court.

Last year a 20-year-old student at Westfield State College was arrested for altering licenses for friends for up to $10. An undercover Registry police officer allegedly visited the student for the purpose of buying a license. The student had to pay $525 in fines and court penalties and his license was revoked.

Individuals face fines and up to five years in jail for faking licenses, Bongiorno said.

But many fake i.d.'s are confiscated by bar and liquor store owners. Employees receive a $100 bounty for each fake license they bring to police, Locke said.