The Russian IT security firm, ElcomSoft, says it has been able to compromise Nikon's Image Authentication system, which is designed to prove whether an image taken with certain Nikon camera has been altered after capture. 

In a posting on its web site, ElcomSoft says it has discovered a flaw in the way Nikon cameras handle digital encryption keys. By exploiting this flaw, ElcomSoft can extract the key from any Nikon camera and then "produce manipulated images with a fully valid authentication signature," according to the company. 

To illustrate this, ElcomSoft has posted several obviously faked photographs that successfully pass validation with Nikon Image Authentication Software, the company says. 

Last year, ElcomSoft similarly compromised Canon's Original Data Security Kit (OSK-E3), which is designed to prove for Canon cameras whether an image has been altered after capture.