City employees from two San Francisco museums held protests this week over plans to introduce a thumbprint-based biometric attendance system.Workers from the de Young and Legion of Honor museums have complained that handing their thumbprints given to a third-party contractor could make their private information more vulnerable to cyber hacking.In a letter to San Francisco Mayor Ed Lee and the Board of Supervisors, union members and staff explained that, “a biometric clock is a violation of employees' rights to personal security and serves to foster a surveillance culture.”The letter claims that the Fine Arts Museums has violated the San Francisco Administration Code, which states that the city cannot disclose employee's private information unless specifically authorised to do so.Raina Johnson, a San Francisco resident and security guard who works the night shift at the museums, told The San Franscico Appeal that “it seems unwise” to hand over irreplaceable personal information at a time when Sony Pictures Entertainment, retail company Target and even the U.S. State Department, have recently been hacked.