Device control transfer
In one embodiment, a device includes a memory to store a first public key indicating security ownership of the device by a first owner, an interface to receive a signature of an intermediate public key signed by a first owner signing service with a first private key, and processing circuitry to load the intermediate public key in the memory, responsively to authenticating the signature, and remove the first public key from the memory, and wherein the interface is to receive a second public key and a signature of the second public key signed by a second owner signing service with an intermediate private key, the processing circuitry is to load a second public key in the memory indicating ownership has been transferred to the second owner responsively to authenticating the signature of the second public key with the intermediate public key, and remove the intermediate public key from the memory.
1 . A system comprising a device including:
a memory to store a first public key indicating security ownership of the device by a first owner;
an interface to receive a signature of an intermediate public key signed by a first owner signing service with a first private key, which forms a first key pair with the first public key; and
processing circuitry to:
load the intermediate public key in the memory in preparation for transferring ownership of the device from the first owner, responsively to authenticating the signature of the intermediate public key with the first public key; and
remove the first public key from the memory;
and wherein:
the interface is to receive a second public key and a signature of the second public key signed by a second owner signing service with an intermediate private key, which forms an intermediate key pair with the intermediate public key, the second public key and a second private key forming a second key pair;
the processing circuitry is to load the second public key in the memory indicating ownership of the device has been transferred to the second owner responsively to authenticating the signature of the second public key with the intermediate public key; and
the processing circuitry is to remove the intermediate public key from the memory.
2 . The system according to claim 1 , wherein the processing circuitry is to overwrite the first public key in the memory with the intermediate public key while loading the intermediate public key in the memory.
3 . The system according to claim 1 , wherein the processing circuitry is to prevent loading of any public key unauthenticated by a given loaded public key; and allows loading of a public key signed by a given private key paired with the given loaded public key.
4 . The system according to claim 1 , wherein the processing circuitry is to purge firmware and certificates signed by the first private key from the memory.
5 . The system according to claim 1 , further comprising the first owner signing service to sign the intermediate public key with the first private key.
6 . The system according to claim 1 , further comprising the second owner signing service to:
generate the second key pair;
sign the second public key with the intermediate private key; and
provide the second public key and the signature of the second public key to the device.
7 . The system according to claim 1 , wherein the processing circuitry is to overwrite the intermediate public key in the memory with the second public key while loading the second public key in the memory.
8 . The system according to claim 1 , wherein:
the interface is to receive a certificate container signed with the second private key; and
the processing circuitry is to load a certificate associated with the signed certificate container in the memory.
9 . The system according to claim 1 , wherein:
the interface is to receive a signature of the firmware; and
the processing circuitry is to store the firmware in the memory or execute the firmware, responsively to authenticating the signature of firmware with a public key of a leaf certificate in a certificate chain with a root certificate of the second owner.
10 . The system according to claim 1 , further comprising a measuring device to:
perform measurements on the device after transferring the ownership of the device; and
compare the measurements performed after transferring ownership of the device to measurements performed before transferring ownership of the device to confirm that the device has not been tampered with.
11 . The system according to claim 1 , wherein the processing circuitry is to:
perform first measurements of the device before transferring the ownership of the device;
sign the first measurements;
provide a first report of the signed first measurements to the second owner signing service;
perform second measurements of the device after transferring the ownership of the device;
sign the second measurements; and
provide a second report of the signed second measurements to the second owner signing service.
12 . The system according to claim 11 , wherein the second owner signing service is to compare the first report to the second report to confirm that the device has not been tampered with.
13 . The system according to claim 1 , wherein:
the interface is to receive the signature of the intermediate public key and a device list signed by the first owner signing service with the first private key, the device list including a device identification of the device; and
the processing circuitry is to load the intermediate public key in the memory in preparation for transferring ownership of the device from the first owner, responsively to authenticating the signature of the intermediate public key and the device list with the first public key.
14 . The system according to claim 13 , wherein the device list includes device identifications of multiple devices.
15 . A control transfer method, comprising:
storing a first public key indicating security ownership of a device by a first owner;
receiving a signature of an intermediate public key signed by a first owner signing service with a first private key, which forms a first key pair with the first public key;
loading the intermediate public key in a memory of the device in preparation for transferring ownership of the device from the first owner, responsively to authenticating the signature of the intermediate public key with the first public key;
removing the first public key from the memory;
receiving a second public key and a signature of the second public key signed by a second owner signing service with an intermediate private key, which forms an intermediate key pair with the intermediate public key, the second public key and a second private key forming a second key pair;
loading the second public key in the memory indicating ownership of the device has been transferred to the second owner responsively to authenticating the signature of the second public key with the intermediate public key; and
removing the intermediate public key from the memory.
16 . The method according to claim 15 , further comprising preventing loading of any public key unauthenticated by a given loaded public key; and allows loading of a public key signed by a given private key paired with the given loaded public key.
17 . The method according to claim 15 , further comprising purging firmware and certificates signed by the first private key from the memory.
18 . The method according to claim 15 , further comprising:
receiving a certificate container signed with the second private key; and
loading a certificate associated with the signed certificate container in the memory.
19 . The method according to claim 15 , further comprising:
receiving a signature of the firmware; and
storing the firmware in the memory or executing the firmware, responsively to authenticating the signature of firmware with a public key of a leaf certificate in a certificate chain with a root certificate of the second owner.
20 . The method according to claim 15 , further comprising:
performing measurements on the device after transferring the ownership of the device; and
comparing the measurements performed after transferring ownership of the device to measurements performed before transferring ownership of the device to confirm that the device has not been tampered with.
21 . The method according to claim 15 , further comprising:
performing first measurements of the device before transferring the ownership of the device;
signing the first measurements;
providing a first report of the signed first measurements to the second owner signing service;
performing second measurements of the device after transferring the ownership of the device;
signing the second measurements; and
providing a second report of the signed second measurements to the second owner signing service.
22 . The method according to claim 21 , further comprising comparing the first report to the second report to confirm that the device has not been tampered with.
23 . The method according to claim 15 , further comprising:
receiving the signature of the intermediate public key and a device list signed by the first owner signing service with the first private key, the device list including a device identification of the device; and
loading the intermediate public key in the memory in preparation for transferring ownership of the device from the first owner, responsively to authenticating the signature of the intermediate public key and the device list with the first public key.
24 . The method according to claim 23 , wherein the device list includes device identifications of multiple devices.