The Justice Department wants to make it easier for law enforcement authorities to obtain search warrants to secretly enter suspects' homes or offices and disable security on personal computers as a prelude to a wiretap or further search, according to documents and interviews with Clinton administration officials.

In a request set to go to Capitol Hill, Justice officials will ask lawmakers to authorize covert action in response to the growing use of software programs that encrypt, or scramble, computer files, making them inaccessible to anyone who does not have a special code or "key," according to an Aug. 4 memo by the department that describes the plan.

Justice officials worry that such software "is increasingly used as a means to facilitate criminal activity, such as drug trafficking, terrorism, white-collar crime, and the distribution of child pornography," according to the memo, which has been reviewed by the Office of Management and Budget and other agencies.

Legislation drafted by the department, called the Cyberspace Electronic Security Act, would enable investigators to get a sealed warrant signed by a judge permitting them to enter private property, search through computers for passwords and install devices that override encryption programs, the Justice memo shows.

The law would expand existing search warrant powers to allow agents to penetrate personal computers for the purpose of disabling encryption. To extract information from the computer, agents would still be required to get additional authorization from a court.

The proposal is the latest twist in an intense, years-long debate between the government and computer users who want to protect their privacy by encrypting documents.

Although Justice officials say their proposal is "consistent with constitutional principles," the idea has alarmed civil libertarians and members of Congress.

"They have taken the cyberspace issue and are using it as justification for invading the home," said James Dempsey, senior staff counsel at the Center for Democracy and Technology, an advocacy group in the District that tracks privacy issues.

Police rarely use covert entry to pave the way for electronic surveillance. For example, federal law enforcement agencies obtained court approval just 34 times last year under eavesdropping statutes to install microphones, according to the 1998 wiretap report issued by the Administrative Office of the Unites States Courts.

David L. Sobel, general counsel at the Electronic Privacy Information Center, predicted the number of secret break-ins by police would soar if the proposal is adopted because personal computers offer such a tantalizing source of evidence for investigators -- including memos, diaries, e-mail, bank records and a wealth of other data.

"Traditionally, the concept of `black bag' jobs, or surreptitious entries, have been reserved for foreign intelligence," Sobel said. "Do we really want to alter the standard for physical entry?"

The proposal follows unsuccessful efforts by FBI Director Louis J. Freeh and other Justice officials to secure laws requiring computers or software to include "back doors" that would enable investigators to sidestep encryption.

Those proposals, most notably one called Clipper Chip, have been criticized by civil libertarians and have received little support in Congress.

In a snub of the administration, more than 250 members of Congress have co-sponsored legislation that would prohibit the government from mandating "back doors" into computer systems.

"We want to help law enforcement deal with the new technologies. But we want to do it in ways that protect the privacy rights of law-abiding citizens," said Rep. Robert W. Goodlatte (R-Va.), who originally sponsored the legislation, known as the Security and Freedom Through Encryption Act. Goodlatte said the Justice Department's proposal might upset the "very finely tuned balance" between law enforcement power and civil liberties.

But Justice Department officials say there is an increasingly urgent need for FBI agents and other federal investigators to get around encryption and other security programs.

"We've already begun to encounter [encryption's] harmful effects," said Justice spokeswoman Gretchen Michael. "What we've seen to date is just the tip of the iceberg."

The proposed law also would clarify how state and federal authorities can seek court orders to obtain software encryption "keys" that suspects might give to others for safekeeping. Although few people share such keys now, officials anticipate that they will do so more often in the future.

Administration officials played down the potential impact on civil liberties. In interviews, two officials said the law would actually bolster privacy protections by spelling out the requirements for court oversight of cyber-surveillance and the limits on how information obtained in a search could be used.

"The administration is supportive of encryption. Encryption is a way to provide privacy, but it has to be implemented in a way that's consistent with other values, such as law enforcement," said Peter P. Swire, the chief White House counselor for privacy. "In this whole debate, we have to strike the right balance."

Computer specialists predict that people under investigation will take countermeasures.

"It's `Spy vs. Spy,' " said Lance Hoffman, director of the Cyberspace Policy Institute at George Washington University, who praised the administration for raising the issue but expressed skepticism about the proposal as it was described to him.

"I'd be leery if I were the government. . . . They have to be real careful," he said.