User authentication in a mobile environment

A data channel transmission can be used to authenticate a voice channel transmission. An authentication server can authenticate the identity of one or more parties to a call where at least one of the parties to the call is using a mobile device. A PKI authentication methodology or other symmetric or asymmetric encryption/decryption methodology can be used in a mobile network environment to identify and authenticate a first user to a second user. The authentication request sent to the third party trusted server can be encrypted, signed and transmitted over a data channel (such as an internet connection or SMS or MMS connection), concurrent with the voice channel transmission. In response to validation by the third party trusted server, the third party trusted server can send an authentication indication to the second user's device, which can display identification information and other (optional) data associated with the first user.