Configuration Systems and Methods for Secure Operation of Networked Transducers

A method for a device to securely receive, from a mobile handset, configuration data over a direct wireless link between the device and the mobile handset, the method performed by the device, the method comprising:

• a) storing, in a nonvolatile memory, (i) a first device private key for a digital signature algorithm, (ii) an authentication token for an initial random number, and (iii) a first set of cryptographic parameters;
• b) receiving from the mobile handset via the direct wireless link (i) a first server public key, (ii) a second set of cryptographic parameters, and (iii) a second random number;
• c) verifying a first signature received from the mobile handset using at least the authentication token;
• d) generating a device signature using at least the second random number and the first device private key;
• e) deriving a first symmetric ciphering key using at least (i) a second device private key and the first server public key, (ii) an Elliptic Curve Diffie Hellman (ECDH) key exchange algorithm, and (iii) the first set of cryptographic parameters;
• f) deriving a third device private key and a third device public key for the second set of cryptographic parameters;
• g) generating a device digital signature over at least the third device public key using the second device private key;
• h) encrypting, with the derived first symmetric ciphering key, at least the derived third device public key and a list of root certificates for the device into a first ciphertext;
• i) sending, via the direct wireless link and to the mobile handset, the first ciphertext and the device digital signature;
• and
• j) receiving, via the direct wireless link and from the mobile handset, a second ciphertext comprising (i) a device certificate for the derived third device public key and
• (ii) a new root certificate for the device, wherein the device decrypts the second ciphertext using at least the first symmetric ciphering key.