Methods and systems for synchronizing a device with a blockchain

A method performed by a device for maintaining synchronization between the device and a blockchain based on a plurality of RF broadcast signals, the method comprising:

• receiving a first RF broadcast signal, the first RF broadcast signal encoding encrypted information about a first state S1 of the blockchain;
• decrypting the information about a first state S1 of the blockchain using a session key:
• storing the information about the first state S1 of the blockchain in a memory of the device;
• wherein after the device misses at least one transmission of an ith RF broadcast signal in a history Hj at at least one time ti,j, the method further comprises:
• receiving a retransmitted version of the ith RF broadcast signal from a subsequent history Hk at a time ti,k where k>j, the retransmitted version of the ith RF broadcast signal encoding encrypted information about an ith state Si of the blockchain;
• decrypting the information about the ith state Si of the blockchain using the session key;
• and
• storing the information about the ith state Si of the blockchain in the memory of the device;
• and
• wherein after the device has stored information about an ith state Si of the blockchain based on an RF broadcast signal from a subsequent history Hk at a time ti,k, the method further comprises both:
• at times ti,m receiving information about later states of the blockchain from an earlier history Hm where m<k and storing the information to a buffer of the memory;
• and
• receiving information about at least an (i+1)th state Si+1 of the blockchain from the subsequent history Hk at times tn,k where n={i+1, i+2 . . . } and storing the information to the buffer of the memory;
• and
• when all of the information resulting from missed transmissions has been obtained from history Hk, combining the information received from the histories Hk and Hm, thereby restoring synchronization, and continuing to obtain information from RF broadcast signals in history Hm.

An apparatus for allowing a device to maintain synchronization with a blockchain for security purposes, the blockchain being in a series of states Si, the apparatus comprising:

• at least one memory;
• and
• at least one processor coupled to the at least one memory and configured to:
• receive information about a first state S1 of a blockchain;
• encrypt the information about the first state S1 of the blockchain with a session key;
• generate a first RF broadcast signal encoding the encrypted information about the first state S1 of the blockchain;
• cause at least one transmitter to transmit the first RF broadcast signal to the device at a first time t1,0;
• receive information about a second state S2 of the blockchain;
• encrypt the information about the second state S2 of the blockchain with the session key;
• generate a second RF broadcast signal encoding the encrypted information about the second state S2 of the blockchain;
• cause the at least one transmitter to transmit the second RF broadcast signal to the device at a second time t2,0, the second time t2,0 and the first time t1,0 being separated by a first interval;
• cause the at least one transmitter to re-transmit the first RF broadcast signal at a third time t1,1, the third time t1,1 and the first time t1,0 being separated by a second interval;
• cause the at least one transmitter to re-transmit the second RF broadcast signal at a fourth time t2,1, the fourth time t2,1 and the second time t2,0 being separated by the second interval;
• cause the at least one transmitter to re-transmit the first RF broadcast signal at a fifth time t1,2, the fifth time t1,2 and the third time t1,1 being separated by a third interval, the third interval being longer than the second interval;
• and
• cause the at least one transmitter to re-transmit the second RF broadcast signal at a sixth time t2,2, the sixth time t2,2 and the fourth time t2,1 being separated by the third interval, wherein:
• a zeroth history H0 comprises a plurality of transmissions at times ti,0, which are first transmissions of respective RF broadcast signals representing ith states Si of the blockchain;
• a jth history Hj comprises a plurality of transmissions at times ti,j, which are jth retransmissions of respective RF broadcast signals representing ith states Si of the blockchain, and there are N histories in total;
• and
• for all i:
• distributions of time intervals Δti,j=ti,j−ti,(j-1) between transmissions of signals encoding information about the ith states Si is such that the device is able eventually to resynchronize with the zeroth history H0 after a period of loss of connectivity;
• and
• a maximum time interval between an initial transmission of a signal encoding an ith state Si of the blockchain and a final retransmission of the signal encoding an ith state of the blockchain is equal to a maximum tolerable duration of a period of loss of connectivity of the device.