Los Angeles - Researchers on Tuesday stood by claims they hacked into copyright protection technology developed by a music industry forum calling the technology inherently flawed.A spokeswoman for the Secure Digital Music Initiative (SDMI) which had offered a $10000 award to hackers who could break into its software by Oct. 7 said the group was still reviewing whether anyone had succeeded.Researchers from Princeton and Rice Universities and the Xerox Palo Alto Research Centers said they hacked into the SDMI's digital watermarking technology which tries to guard against hacking using hidden signals in the files.The researchers questioned whether the digital watermark approach was a feasible way to create an industry-wide standard for secure distribution of music online.Right now we don't think it's feasible that watermarking technology is mature enough to be used in the kind of application the Secure Digital Music Initiative (SDMI) had in mind said Edward Felten a faculty member of Princeton University one of the researchers claiming to have defeated the proposed technology.During the challenge period our team of researchers... successfully defeated all four of the watermarking challenges by rendering the watermarks undetectable without significantly degrading the audio quality of the samples the group said on its Web site (http:/www.cs.princeton.edu/sip/sdmi).Our success on these challenges was confirmed by SDMI's email server the group said.If the hacking claims prove true it would be another embarrassing setback for the SDMI which has been criticized for delays and setbacks. The group launched its $10000 contest in September challenging anybody to hack into its software.Several hacker groups called for a boycott of the contest saying record labels were trying to limit consumers' fair use rights to make copies of music they purchase for their own personal use in a car stereo or lap-top computer.Rumors had circulated for two weeks that several hacks had breached the technology. Last week the SDMI denied claims -- first reported by online magazine Salon.com -- that its technology had been defeated during the contest which ended Oct. 7.The group said 447 submissions were received during the contest and the submitted attacks were still under review.An SDMI spokeswoman said the group was still testing the results and it's too early to say if anyone successfully hacked the technology. She added there would be no public report on the contest before the SDMI holds its next meeting Nov. 8-10.David Leibowitz chairman of San Diego-based Verance Corp. said on Tuesday his company had received official word from the SDMI that its watermarking technology had not been successfully hacked in the public challenge. Verance is one of four companies which proposed watermarks to the SDMI.The big five major record labels including Seagram Co. Ltd.'s Universal Music Bertelsmann AG's BMG Sony Corp.'s Sony Music Time Warner Inc.'s Warner Music Group and EMI Group Plc (news - web sites)'s EMI Music are all founding members of SDMI.These labels have launched a crusade against digital piracy and are involved in a high-profile lawsuit against the widely popular song-swap service Napster (news - web sites) Inc. -- By Sue Zeidler - Reuters