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We propose a privacy conserving protocol to share location information with groups of trusted agents (e.g. friends) using a mobile device. All information published by the user is cryptographically secured and authenticated. Furthermore, we employ methods to make it hard for third parties to derive a user's relationships from communication patterns. Users can create multicast groups spontaneously and maintain these efficiently. In contrast to previous solutions, our approach does not rely on any dedicated or trusted network infrastructure for coordination or communication. For our prototype implementation messages are pushed to the listening group members with low overhead, by using existing publicly available and accessible communication infrastructure (IRC). Finally, we present a cost and privacy analysis of the proposed protocol.