ElcomSoft Co. Ltd. researched Nikon's Image Authentication System, a secure suite validating if an image has been altered since capture, and discovered a major flaw. The flaw allows anyone producing forged pictures that will successfully pass validation with Nikon's Image Authentication Software. The weakness lies in the manner the secure image signing key is being handled in Nikon digital cameras.
Press release: ElcomSoft Discovers Vulnerability in Nikon's Image Authentication System http://www.elcomsoft.com/PR/nikon_110428_en.pdf
A set of forged images that are successfully passing validation http://www.elcomsoft.com/nikon.html
ElcomSoft Corporate Blog: Some Technical Details; World's Famous Hoax Photos http://blog.crackpassword.com/2011/04/nikon-image-authentication-system-compromised/