US 11,727,391 B2
Computer-implemented methods and systems for validating tokens for blockchain-based cryptocurrencies
Craig Steven Wright, London (GB); and Stephane Savanah, London (GB)
Assigned to nChain Licensing AG, Zug (CH)
Appl. No. 16/92,744
Filed by nChain Licensing AG, Zug (CH)
PCT Filed Apr. 10, 2017, PCT No. PCT/IB2017/052061
§ 371(c)(1), (2) Date Oct. 10, 2018,
PCT Pub. No. WO2017/178955, PCT Pub. Date Oct. 19, 2017.
Claims priority of application No. 1606065 (GB), filed on Apr. 11, 2016.
Prior Publication US 2019/0130391 A1, May 2, 2019
Int. Cl. G06Q 20/36 (2012.01); G06F 21/30 (2013.01); G06Q 20/06 (2012.01); G06F 21/64 (2013.01); G06Q 40/00 (2023.01); G06Q 20/38 (2012.01)
CPC G06Q 20/3672 (2013.01) [G06F 21/30 (2013.01); G06F 21/645 (2013.01); G06Q 20/065 (2013.01); G06Q 20/0658 (2013.01); G06Q 20/3678 (2013.01); G06Q 20/389 (2013.01); G06Q 20/3829 (2013.01); G06Q 40/00 (2013.01); G06Q 2220/00 (2013.01)] 16 Claims
OG exemplary drawing
 
1. A computer-implemented method of determining validity of a token transfer in a first transaction over a communications network,
wherein the first transaction comprises:
a first redeem script comprising a metadata field including information about a token to be transferred;
a quantity of cryptocurrency associated with the token; and
an indication of the token transfer from a first user device to a second user device, and
wherein the computer-implemented method comprises:
determining, by a processor of the second user device, that the token in an input to the first transaction has not been authorised;
querying, by the processor, in response to the determining that the token has not been authorised, a peer-to-peer distributed ledger to identify an authenticated transaction associated with the token, wherein querying the peer-to-peer distributed ledger comprises:
a) determining a first previous transaction ID indicated in the first transaction;
b) identifying a prior transaction recorded in the peer-to-peer distributed ledger, wherein a transaction ID of the prior transaction corresponds with the first determined previous transaction ID;
c) determining whether a redeem script of the prior transaction has been signed by an authorised signatory;
d) responsive to determining that the redeem script of the prior transaction has been signed by the authorised signatory, identifying the prior transaction as the authorised transaction;
e) responsive to determining that the redeem script of the prior transaction has not been signed by the authorised signatory;
determining a second previous transaction ID indicated in the prior transaction as the determined previous transaction ID; and
identifying a further prior transaction recorded in the peer-to-peer distributed ledger as the prior transaction, wherein a third previous transaction ID of the further prior transaction corresponds with the second previous transaction ID; and
f) iteratively performing steps c) to e) until no further prior transactions are identified;
determining, by the processor, responsive to identifying the authenticated transaction associated with the token, that the token is valid; and
recording, by the processor, responsive to determining that the token transfer is valid, the token transfer.