# Cross-Domain Discovery of Communication Peers. Identity Mapping and Discovery Services (IMaDS)

## TL;DR

IMaDS is a scalable, service-independent discovery system enabling web-based peer-to-peer communication by mapping user identities across domains, providing reachability, presence, and privacy options.

## Contribution

It introduces a novel global discovery service that supports cross-domain identity mapping, dynamic context-aware searches, and privacy-preserving user discovery for WebRTC applications.

## Key findings

- Supports multiple identifier formats and privacy options
- Uses DHT-based directory for scalable identity resolution
- Enables dynamic cross-domain user discovery

## Abstract

The upcoming WebRTC-based browser-to-browser communication services present new challenges for user discovery in peer-to-peer mode. Even more so, if we wish to enable different web communication services to interact. This paper presents Identity Mapping and Discovery Service (IMaDS), a global, scalable, service independent discovery service that enables users of web-based peer-to-peer applications to discover other users whom to communicate with. It also provides reachability and presence information. For that, user identities need to be mapped to any compatible service identity as well as to a globally unique, service-independent identity. This mapping and discovery process is suitable for multiple identifier formats and personal identifying properties, but it supports user-determined privacy options. IMaDS operates across different service domains dynamically, using context information. Users and devices have profiles containing context and other specific information that can be discovered by a search engine. The search results reveal the user's allocated globally unique identifier (GUID), which is then resolved to a list of the user's service domains identities, using a DHT-based directory service. Service-specific directories allow tracking of active endpoints, where users are currently logged on and can be contacted.