The Patriot Act has been cited as a reason for caution when considering cloud computing using providers in the United States. Some fear that this law, passed in the wake of the September 11 2001 terrorist attacks, could permit US government agencies to access their private data if it is stored at a datacentre in the US.

Lawyer Jeff Bullwinkel -- associate general counsel and director of legal and corporate affairs at Microsoft Australia and New Zealand -- in , says there is no reason to fear the Patriot Act specifically. However, his comments are scarcely a reassurance. The US government can access your data with or without the Patriot Act, he says.

The Act merely gathers in one place a series of amendments to other legislation, Bulwinkel writes: "Therefore, to the extent the US government can access data, it is generally not through the Patriot Act, but it may be through existing laws amended by the Patriot Act, as well as decades-old judicial decisions in the US providing for extraterritorial subpoena power in limited circumstances.

"In fact," he adds, "US courts have long held that a company with a presence in the US is obligated to respond to a valid demand by the US government for information -- regardless of the physical location of the information -- so long as the company retains custody or control over the data."

A key court decision in this area was taken as long ago as 1984 in the case of the United States v. Bank of Nova Scotia. The court required the US branch of a Canadian bank to produce documents held in the Cayman Islands, for use in US criminal proceedings." Some will argue that this decision went too far, Bulwinkel acknowledges; "But what many overlook is that the legal principle on extraterritorial jurisdiction -- requiring companies with contacts or presence within a territory to comply with lawful requests for information by the government in that territory -- has long been followed in many other countries."