Wireless security protocol
This disclosure relates to a data storage device. A data port transmits data between a host computer system and the data storage device over a data channel. The device repeatedly broadcasts advertising packets over a wireless communication channel different from the data channel. Each advertising packet comprises a random value and a message authentication code calculated based on the random value and an identity key. The identity key is readable by a device to be connected and in proximity of the data storage device out of band of the data channel and the communication channel. The identity key enables the device to be connected to verify the message authentication code based on the random value and the identity key to thereby authenticate the data storage device.
1. A data storage device comprising:
a data path comprising:
a data port configured to transmit data between a host computer system and the data storage device over a data channel;
a non-volatile storage medium configured to store encrypted user content data; and
a cryptography engine connected between the data port and the storage medium, wherein the cryptography engine is configured to use a cryptographic key to decrypt the encrypted user content data stored on the non-volatile storage medium in response to a request from the host computer system;
a data store configured to store an identity key; and
an access controller configured to:
repeatedly broadcast advertising packets over a wireless communication channel different from the data channel, wherein:
each advertising packet comprises a random value and a message authentication code calculated based on the random value and the identity key;
the identity key is readable by a device to be connected and in proximity of the data storage device out of band of the data channel and the communication channel; and
the identity key is configured to enable the device to be connected to verify the message authentication code based on the random value and the identity key to authenticate the data storage device;
receive, from the device to be connected, a response based on the identity key and the message authentication code;
establish, based on the response, a secure wireless communication channel with the device to be connected as a manager device; and
generate, responsive to the manager device taking ownership of the data storage device, the cryptographic key.
2. The data storage device of claim 1 , wherein:
the data store is further configured to store a data storage device certificate that is configured to be cryptographically linked to a root certificate that is accessible by the device to be connected; and
the access controller is further configured to:
calculate a signature verified by the data storage device certificate; and
send the data storage device certificate and the signature to the device to be connected to enable the device to be connected to authenticate the data storage device.
3. The data storage device of claim 2 , wherein the data storage device certificate comprises a hash value of the identity key to bind the data storage device certificate to the data storage device from which the identity key is readable out of band.
4. The data storage device of claim 2 , wherein:
the root certificate is accessible by the device to be connected through an application installed on the device to be connected from an authenticated provider cryptographically associated with the root certificate.
5. The data storage device of claim 1 , wherein an advertising address of the broadcast advertising packets is selected uniformly at random.
6. The data storage device of claim 1 , wherein:
each advertising packet further comprises a service identifier of the data storage device; and
the message authentication code is calculated based on the random value, the identity key and the service identifier.
7. The data storage device of claim 1 , wherein the access controller is further configured to:
receive, in the response from the device to be connected, a first nonce value;
generate a second nonce value;
broadcast through the wireless communication channel, the second nonce value;
derive a derived cryptographic key from the identity key, the first nonce value and the second nonce value using a key-derivation function; and
secure the wireless communication channel with the device to be connected using the derived cryptographic key.
8. The data storage device of claim 1 , wherein the communication channel uses a low energy wireless communication protocol.
9. The data storage device of claim 1 , wherein the identity key is readable by the device to be connected by means of a quick response (QR) code affixed to the data storage device or by means of a near field communication (NFC) tag integrated in the data storage device.
10. A client device comprising:
a processor; and
a memory, the memory comprising instructions executable by the processor to:
receive an identity key from a data storage device out of band of a wireless communication channel with the data storage device, wherein the data storage device comprises a data path comprising:
a data port configured to transmit data between a host computer system and the data storage device over a data channel;
a non-volatile storage medium configured to store encrypted user content data; and
a cryptography engine connected between the data port and the storage medium, wherein the cryptography engine is configured to use a user content cryptographic key to decrypt the encrypted user content data stored on the non-volatile storage medium in response to a request from the host computer system;
receive an advertisement packet broadcast by the data storage device over the wireless communication channel, wherein the advertisement packet comprises a random value and a message authentication code calculated by the data storage device based on the random value and the identity key;
verify the message authentication code based on the random value and the identity key to authenticate the data storage device;
upon authentication of the data storage device, generate a derived cryptographic key based on the identity key to secure the wireless communication channel with the data storage device; and
take, responsive to establishing the secure wireless communication channel, ownership of the data storage device as a manager device, wherein the data storage device is configured to generate, responsive to the manager device taking ownership of the data storage device, the user content cryptographic key.
11. The client device of claim 10 , wherein the memory further comprises instructions executable by the processor to access a root certificate cryptographically linked to a certificate of the data storage device.
12. A method comprising:
generating, by a data storage device, a random value, wherein the data storage device comprises a data path comprising:
a data port configured to transmit data between a host computer system and the data storage device over a data channel;
a non-volatile storage medium configured to store encrypted user content data; and
a cryptography engine connected between the data port and the storage medium, wherein the cryptography engine is configured to use a user content cryptographic key to decrypt the encrypted user content data stored on the non-volatile storage medium in response to a request from the host computer system;
calculating, by the data storage device and based on the random value and an identity key a message authentication code, wherein:
the identity key is readable by a device to be connected in proximity of the data storage device out of band of a wireless communication channel between the device to be connected and the data storage device; and
the identity key enables the device to be connected to verify the message authentication code based on the random value and the identity key to authenticate the data storage device;
broadcasting, by the data storage device, an advertising packet over the wireless communication channel, wherein the advertising packet comprises the random value and the message authentication code calculated based on the random value and the identity key;
receiving, by the data storage device and from the device to be connected, a response based on the identity key and the message authentication code;
establishing, by the data storage device and based on the response, a secure wireless communication channel with the device to be connected as a manager device; and
generating, by the data storage device and responsive to the manager device taking ownership of the data storage device, the user content cryptographic key.
13. The method of claim 12 , further comprising in response to receiving a connection request from the device to be connected, sending a data storage device certificate issued by the data storage device to the device to be connected, the data storage device certificate comprising a hash value of the identity key to bind the data storage device certificate to the data storage device from which the identity key is readable out of band.
14. The method of claim 13 , wherein the data storage device certificate is cryptographically linked to a root certificate that is accessible by the device to be connected.
15. The method of claim 13 , further comprising:
calculating, by the data storage device, a hash of:
the identity keys;
a nonce received from the device to be connected; and
the random value; and
calculating, by the data storage device, a signature for the hash based on the identity key and verified by the data storage device certificate.
16. The method of claim 13 , further comprising:
calculating, by the data storage device, a signature of the data storage device certificate; and
in response to receiving the connection request from the device to be connected, sending, by the data storage device, the signature to the device to be connected.
17. The method of claim 16 , wherein the signature is verified by the data storage device certificate by using a private key to calculate the signature, wherein the private key is verified by the data storage device certificate.
18. The method of claim 17 , wherein the data storage device certificate comprises a public key, corresponding to the private key, for verifying the signature.
19. The method of claim 12 , further comprising:
receiving, by the device to be connected and from the data storage device:
a data storage device certificate issued by the data storage device; and
a signature calculated by the data storage device based on the identity key and verified by the data storage device certificate;
verifying, by the device to be connected, the data storage device certificate against a root certificate;
verifying, by the device to be connected, the signature against the data storage device certificate; and
upon verification of the signature, securing, by the device to be connected, the wireless communication channel with the data storage device.
20. A data storage device comprising:
a processor;
a memory;
a data path comprising:
a data port configured to transmit data between a host computer system and the data storage device over a data channel;
a non-volatile storage medium configured to store encrypted user content data; and
a cryptography engine connected between the data port and the storage medium, wherein the cryptography engine is configured to use a user content cryptographic key to decrypt the encrypted user content data stored on the non-volatile storage medium in response to a request from the host computer system;
means for generating a random value;
means for calculating, based on the random value and an identity key a message authentication code, wherein:
the identity key is readable by a device to be connected and in proximity of the data storage device out of band of a wireless communication channel between the device to be connected and the data storage device; and
the identity key enables the device to be connected to verify the message authentication code based on the random value and the identity key to authenticate the data storage device;
means for broadcasting an advertising packet over the wireless communication channel, wherein the advertising packet comprises the random value and the message authentication code calculated based on the random value and the identity key;
means for receiving, from the device to be connected, a response based on the identity key and the message authentication code;
means for establishing, based on the response, a secure wireless communication channel with the device to be connected as a manager device; and
means for generating, responsive to the manager device taking ownership of the data storage device, the user content cryptographic key.