An attacker examines a target application's code or configuration files to find credential or key material that has been embedded within the application or its files. Many services require authentication with their users for the various purposes including billing, access control or attribution. Some client applications store the user's authentication credentials or keys to accelerate the login process. Some clients may have built-in keys or credentials (in which case the server is authenticating with the client, rather than the user). If the attacker is able to locate where this information is stored, they may be able to retrieve these credentials. The attacker could then use these stolen credentials to impersonate the user or client, respectively, in interactions with the service or use stolen keys to eavesdrop on nominally secure communications between the client and server.