Secure remote authentication of local machine services using secret sharing

1. A method for authentication of a computing device having a copy of its operating system stored in a protected location over a network on which an authentication server is listening, comprising the steps of:

dividing a secret, at the computing device, into a first share and a second share;

destroying the secret after the dividing step;

transmitting the second share not using the network, together with a unique identifier, to a pre-designated location;

erasing, after the transmitting, the second share from the computing device;

storing the first share at the computing device;

broadcasting the unique identifier over the network;

receiving the second share over the network from the authentication server; and

reconstructing the secret using the received second share and the stored first share;

accessing, using the reconstructed secret, the protected location and obtaining the copy of the operating system; and

booting the computing device with the obtained copy of the operating system.

2. The method of claim 1 , further comprising the unique identifier selected from the group of unique data consisting of a serial number, machine fingerprint data, a network authorization code, a public key, and a session nonce.

3. The method of claim 2 , further comprising hashing part or all of the unique data to construct the unique identifier.

4. The method of claim 1 , further comprising shrouding of the first and second shares.

5. The method of claim 1 , where the protected location is a trusted computing base.

6. The method of claim 1 , where the protected location is external to the computing device.

7. A method for authentication of a computing device having a copy of its operating system stored in a protected location over a network on which one or more authentication servers are listening, comprising the steps of:

dividing, at the computing device, a secret into N shares such that a threshold number of shares represented by a number K, being less than N, will be required to reconstruct the secret;

destroying the secret after the dividing step;

transmitting X of the N shares not using the network, X being less than K, together with a unique identifier, to one or more pre-designated locations;

erasing, after the transmitting step, the X transmitted shares from the computing device until Y shares remain, such that X+Y equals K;

storing the Y remaining shares at the computing device;

broadcasting the unique identifier over the network;

receiving the X transmitted shares over the network from one or more of the authentication servers;

reconstructing the secret using the received X transmitted shares and the stored Y remaining shares;

accessing, using the reconstructed secret, the protected location and obtaining the copy of the operating system; and

booting the computing device with the obtained copy of the operating system.

8. The method of claim 7 , further comprising, prior to the transmitting, hashing part or all of the unique identifier.

9. The method of claim 7 , further comprising, prior to the transmitting, shrouding one or more of the X transmitted shares.

10. The method of claim 7 , where the protected location is a trusted computing base.

11. The method of claim 7 , where the protected location is external to the computing device.