A voice call system and a method and apparatus for identifying a voice caller are disclosed. The system includes a call originator apparatus 10 and a called party apparatus 20. At least one trusted user identity is formed at the call originator apparatus 10, ideally in a trusted platform module 12 configured according to a Trusted Computing Platform Alliance (TCPA) specification. The called party apparatus 20 checks the trusted user identity when establishing a new voice call. Advantageously, an identity of the voice caller using the call originator apparatus is confirmed in a reliable and trustworthy manner, even when the voice call is transported over an inherently insecure medium, e.g. an open computing system like the internet 30. Preferred embodiments of the invention use IP telephony, such as SIP (session initiation protocol) or H.323 standard voice telephony.