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Cyber extortionists pose growing threat to tech firms

1 August 2014 Last updated at 23:04 BST

For people making a living online, someone killing their internet connection could put their entire business in jeopardy.

This is the threat a new wave of cyber extortionists are holding over tech companies.

The weapon the extortionists use is a distributed denial of service (DDoS) attack to block access to their websites, accompanied by demands for money to stop the attack.

BBC Newsnight's David Grossman reports.