Under current law, investigators can examine the files on a computer seized during a legal search, but they do not have the authority to crack passwords or open encrypted documents.

The draft legislation would allow law enforcement authorities armed with sealed search warrants to secretly gain access to suspects' homes and computers to gain keys and passwords to unlock encrypted files, to implant "recovery devices", or to disable encryption and security software.

However, investigators would still have to gain additional court authorisation to extract information from the computer.

Privacy rights

The proposed law would open the way to more secret searches

Both the government and civil liberties advocates agree that encryption and improved computer security are essential to the continued growth of the Internet and electronic commerce.

But the two sides sharply disagree on how to strike a balance between the privacy rights of law-abiding citizens and the need for law enforcement authorities to monitor criminal activity.

In a draft letter asking Congress to consider the Cyberspace Electronic Security Act (CESA), Acting Assistant Attorney General Jon Jennings writes, "the same encryption products that help facilitate confidential communications between law-abiding citizens also pose a significant and undeniable public safety risk when used to facilitate and mask illegal and criminal activity."

Authorities fear that encryption is increasingly used "to promote criminal activity, such as drug trafficking, terrorism, white collar crime, and the distribution of child pornography."

Invasion of privacy

Justice Department officials say the proposed legislation is consistent with the constitution, but civil libertarians say the government is using the threat of technology as an excuse to trample people's rights.

"They are using the cyberspace issue of encryption and its impact on law enforcement for justification to invade the home," says James Dempsey with the Centre for Democracy and Technology.

Mr Dempsey adds that the proposed bill goes far beyond giving investigators access to encrypted files by allowing them to examine a computer for the user's passwords.

And he is not satisfied with the requirement that the government would have to obtain a court order to perform such searches.

"Judges rarely deny search warrant requests and wiretap requests, but no matter how high the standard, nothing justifies government secretly opening our homes," he says.