Fixed client identification system for positive identification of client to server
A tamperproof ClientID system to uniquely identify a client machine is invoked upon connection of a client application to a backend. Upon initial connection, the backend issues a unique ClientID containing a checksum. The client-application prepares at least two different scrambled versions of the ClientID and stores them in respective predetermined locations on the client machine. Upon subsequent connection to the backend, the client application retrieves and unscrambles the values at the two locations, verifies the checksums and compares the values. If the checksums are both correct and the values match, the ClientID value is sent to the backend, otherwise the client application sends an error code.
1. A method for storing data to positively identify a client machine running a client application to a backend, comprising:
executing a ClientID storage process, including
upon connection by the client application to the backend, generating a unique ClientID containing a checksum at the backend for the client machine,
sending the ClientID to the client application,
reversibly scrambling the ClientID with the client application at the client machine and storing a first scrambled version of the ClientID at a first predetermined location on the client machine, and
reversibly scrambling the ClientID with the client application at the client machine and storing a second scrambled version different from the first version of the ClientID at a second predetermined location on the client machine; and
executing a ClientID retrieval process with the client application when the client application subsequently attempts to connect to the backend, including
retrieving the first and second scrambled versions of the ClientID stored in the first and second locations and unscrambling the first and second scrambled versions of the ClientID using first and second keys to obtain first and second unscrambled values,
running a checksum operation on each of the first and second unscrambled values to verify that each has the correct checksum, and
comparing the first and second unscrambled values to determine an occurrence of a match between the first and second unscrambled values.
2. The method of claim 1 , wherein the retrieval process further comprises:
if the first and second unscrambled values retrieved from the first and second locations have the correct checksum and match each other, reporting the retrieved ClientID to the backend.
3. The method of claim 2 , wherein the retrieval process further comprises:
if the first and second unscrambled values retrieved from the first and second locations lack the correct checksum and match each other, reporting an error to the backend.
4. The method of claim 1 , wherein the storage process further comprises encrypting a value of the generated ClientID at the backend and storing the encrypted value of the ClientID on the backend in a ClientID record.
5. The method of claim 1 , wherein the first and second keys are different.
6. The method of claim 1 , wherein one of the first and second locations is a registry.
7. The method of claim 1 , wherein one of the first and second locations is a system configuration file.
8. The method of claim 1 , wherein the first and second locations are a registry and a system configuration file.
9. A system comprising:
a client machine connected to a backend, wherein
upon connection by a client application to the backend, the backend is configured to generate a unique ClientID containing a checksum for the client machine and send the ClientID to the client machine;
the client machine is configured to reversibly scramble the ClientID with the client application and store a first scrambled version of the ClientID at a first predetermined location on the client machine, the client machine is further configured to reversibly scramble the ClientID with the client application and store a second scrambled version different from the first scrambled version of the ClientID at a second predetermined location on the client machine and
a ClientID retrieval process executed by the client application as the client application subsequently attempts to connect to the backend, the ClientID retrieval process is configured to retrieve the first and second scrambled versions of the ClientID stored in the first and second locations and unscramble the first and second scrambled versions of the ClientID using first and second keys to obtain first and second unscrambled values, the ClientID retrieval process is further configured to execute a checksum operation on each of the first and second unscrambled values to verify that each has the correct checksum, and compare the first and second unscrambled values to determine a state of matching between the first and second unscrambled values.
10. The system of claim 9 , wherein the retrieval process is further configured to report the retrieved ClientID to the backend if the first and second unscrambled values have the correct checksum and match each other.