Systems and methods for securing the manufacturing supply chain
Securing the manufacturing supply chain with digital certificates. A token is coupled to a manufacturing station and enabled via a personal identification number. The token includes a counter limiting the maximum number of certificates to be signed, and compares a serial number of a digital certificate to a tracked serial number. In some embodiments, the token is linked to a particular manufacturing station once the token is enabled.
1. A method for signing digital certificates, the method comprising:
cryptographically coupling a token to a manufacturing station, wherein the token includes a counter representing a number of signed digital certificates and a maximum value for the counter;
enabling the token based on a personal identification number received by the manufacturing station;
determining that a value stored in the counter is less than the maximum value;
in response to determining that the value stored in the counter is less than the maximum value;
obtaining a public key from an electronic device,
binding the public key to a digital certificate that is currently unsigned,
determining that a serial number associated with the digital certificate matches a serial number associated with a serial number tracker in the token, and
in response to determining that the serial number associated with the digital certificate matches the serial number associated with the serial number tracker in the token,
signing the digital certificate with the public key;
modifying the serial number in the serial number tracker to the next serial number expected;
incrementing the counter following the signing of the digital certificate; and
returning the signed digital certificate to the electronic device.
2. The method of claim 1 , wherein enabling the token includes verifying that the personal identification number received by the manufacturing station matches a personal identification number stored in the token.
3. The method of claim 1 , further comprising linking the token to the manufacturing station.
4. The method of claim 3 , further comprising verifying that the token is cryptographically coupled to the manufacturing station to which the token is linked.
5. The method of claim 4 , further comprising disabling the token when the token is coupled to a manufacturing station that is different than the manufacturing station to which the token is linked.
6. The method of claim 1 , further comprising disabling the token when a trusted platform module of the manufacturing station is not valid.
7. The method of claim 1 , further comprising providing to an external device a listing of the digital certificates previously signed.
8. The method of claim 7 , further comprising signing the serial number in the serial number tracker when the digital certificate is signed.
9. The method of claim 8 , further comprising:
comparing the listing to a previous listing to determine if unauthorized manufacturing occurred; and
flagging the certificates of electronic devices manufactured without authorization.
10. The method of claim 1 , further comprising determining that the token was issued to the manufacturing station.