Heartbleed bug: Public urged to reset all passwords
9 April 2014 Last updated at 22:32 BST
Several technology firms are urging people to change all their passwords after the discovery of a major security flaw.
The bug, nicknamed Heartbleed, could be used to access data thought to be protected by OpenSSL - encryption software commonly used by internet services.
Professor David Stupples of City University advised people to change passwords on services like email accounts and banking.