Methods and Systems for securely distributing 
software in a subscription-based environment are provided. In an example embodiment, a Game Security Facility (“GSF”) associated with a 
game server is used to manage secure communications with game clients. The GSF typically manages 
secure communication of the accounting and billing information and 
secure communication of game session data. In typical operation, the 
game client generates a pass-
phrase that transparently includes a 
unique identifier of the 
machine upon which the subscription 
software will reside. RSA-type key pairs that are then generated using this pass-
phrase will be associated uniquely with both the 
game player and with the 
machine upon which the 
software resides, thus preventing unauthorized 
copying to another 
machine or unauthorized use by a 
third party. A public key generated using this pass-
phrase is forwarded to the GSF, which uses it to generate a unique one-time random 
session key (for use as a symmetric key) for each session with the 
game client. The 
session key is then encrypted for the 
game client using the public key of the 
client. Session data, including the original game files downloaded upon successfully subscribing, are then transmitted between the 
game server and the game 
client using encrypted versions of the 
session key. In one embodiment, the game 
client can 
upgrade the machine upon which the subscription data resides, cause the session keys to be reissued using a new public key, and retain access to previously downloaded data.