Kevin Mitnick can certainly empathize with Kim DotCom.

Mitnick, one of the best-known computer hackers of all time, knows what it is to be hunted by the American government and to face jail time as a result. That may be why Mitnick cheered DotCom on via Twitter.

James Martin/CNET

DotCom, the founder of cloud-storage service MegaUpload is trying to fend off attempts by U.S. officials to extradite him from New Zealand and try him on various charges, including criminal copyright violations and wire fraud.

"I hope you win," Mitnick wrote to DotCom last night. "I saw this on YouTube and thought of you."

Embedded in Mitnick's Twitter post was a link to a YouTube music video from singer Tom Petty. The song was "I Won't Back Down." Critics would caution DotCom to think twice before taking advice from Mitnick.

Mitnick spent over four years in jail for computer fraud and other related charges. He hacked Motorola, NEC, Nokia and other systems. Some of his prison time was served in solitary confinement because authorities were under the impression that Mitnick could start a nuclear war simply by whistling into a payphone.

DotCom, who received support yesterday from Apple co-founder Steve Wozniak, appeared grateful for the shout out from Mitnick, who is now a security consultant and public speaker.

"Hi Kevin," DotCom wrote. "Nice to get a tweet from the legend."