The security and privacy levels of some of these wearable devices are being considered by some users as they have the ability to hold and distribute sensitive health information.[27] One study analysed the security and privacy levels of wearable devices.[28] The study found that there were specific aspects where users of wearable devices may be vulnerable to privacy breaches; this includes the storage and transmission of unencrypted data, a lack of physical security controls and a lack of authentication and authorisation by the user. There is a need to develop strong authentication mechanisms in wearable technologies so prevent losses of security and confidentiality in users.[28]