	US 11,989,725 B2
	Blockchain-implemented systems and methods for secure access control
Silvia Bartolucci, London (GB); Pauline Bernat, London (GB); and Daniel Joseph, London (GB)
Assigned to nChain Licensing AG, Zug (CH)
Appl. No. 16/968,538
Filed by nChain Licensing AG, Zug (CH)
PCT Filed Feb. 1, 2019, PCT No. PCT/IB2019/050815 § 371(c)(1), (2) Date Aug. 7, 2020, PCT Pub. No. WO2019/155333, PCT Pub. Date Aug. 15, 2019.
Claims priority of application No. 1802148 (GB), filed on Feb. 9, 2018.
Prior Publication US 2021/0042745 A1, Feb. 11, 2021
Int. Cl. G06Q 20/38 (2012.01); G06Q 20/06 (2012.01); G06Q 20/40 (2012.01); H04L 9/32 (2006.01); H04L 9/00 (2022.01)

CPC G06Q 20/3825 (2013.01) [G06Q 20/065 (2013.01); G06Q 20/401 (2013.01); H04L 9/3247 (2013.01); G06Q 2220/00 (2013.01); H04L 9/50 (2022.05)]

13 Claims

1. A computer-implemented method for controlling access to a resource performed by a first party (A) computer system having a first memory and processor, said access being conditional upon a task being performed by a second party (B) computer system having a second memory and processor, wherein the task includes broadcasting a transaction (Tx^A) on a blockchain, the method including:

collaborating, by the first party (A) computer system, with the second party (B) computer system to create a first multi-signature address (α_B) and second multi-signature address (β_A);

broadcasting, by the first party (A) computer system, a deposit mechanism (D_x) that allocates a resource (x) to the first multi-signature address (α_B);

building, by the first party (A) computer system, a task, said task including the broadcast of a transaction (T_x^A), and sending said task to the second party (B) computer system for broadcast on the blockchain, said transaction having a locking-output (d) allocated to the second multi-signature address (β_A);

creating and sending, by the first party (A) computer system, a locking mechanism (R_x^B) to the second party (B) computer system, or receiving a locking mechanism (R_x^B) from the second party (B) computer system, wherein an input to said locking mechanism is the resource (x) and the locking-output (d), which are locked by their respective multi-signatures, and an output (d+x) is the resource and the locking-output;

signing, by the first party (A) computer system, the first multi-signature address (α_B) and second multi-signature address (β_A), enabling the second party (B) computer system to sign the first multi-signature address (α_B) and second multi-signature address (β_A), thus unlocking the input to the locking mechanism (R_x^B) enabling the output (d+x) to be allocated to an address (γ_B) accessible by the second party (B) computer system, wherein said output is conditional upon both the resource and the locking-output being allocated to their multi-signature addresses on the blockchain;

confirming, by the first party (A) computer system, the broadcast of the transaction (T_x^A); and

in response to confirming the broadcast of the transaction (T_x^A), broadcasting, by the first party (A) computer system, the locking mechanism (R_x^B) on the blockchain causing allocation of the locking-output (d) to the second multi-signature address (β_A) and enabling the second party (B) computer system to access the resource and the locking-output (d+x).