You are looking at documentation for an older release. Not what you want? See the current release documentation.
This section is about configuring the 2-legged OAuth scenario in OpenSocial. (Reference: OpenSocial.org)
For more information, visit 2-legged OAuth for the OpenSocial REST API.
$ openssl req -newkey rsa:1024 -days 365 -nodes -x509 -keyout testkey.pem \
     -out testkey.pem -subj '/CN=mytestkey'
$ openssl pkcs8 -in testkey.pem -out oauthkey.pem -topk8 -nocrypt -outform PEM
Edit
    container.js
    and change the following parameter to point to your private key and key name.
  
"gadgets.signingKeyFile" : "oauth.pem", "gadgets.signingKeyName" : "oauthKey",