Method of using a blockchain

1 . A computer-implemented method of processing a higher-level contributor transaction evidencing a higher-level contribution of a higher-level contributor, wherein contributors having respective levels in a defined hierarchy contribute to a work, wherein one or more lower-level contributors provide, to the higher-level contributor, one or more lower-level contributions respectively, and the higher-level contributor provides a higher-level contribution responsive to one or more lower-level contributions, wherein the higher-level contributor transaction comprises:

one or more inputs comprising:

one or more pointers to one or more spendable outputs of one or more lower-level contributor transactions, the one or more lower-level contributor transactions containing one or more lower-level contribution commitments evidencing the one or more lower-level contributions respectively; and

one or more transaction signatures of the higher-level contributor satisfying one or more signature challenges of the one or more spendable outputs;

wherein the higher-level contributor transaction contains a higher-level contribution commitment computed from the higher-level contribution, wherein the one or more pointers and the contribution commitments represent a relationship between the higher-level contributor and the one or more lower-level contributors within the defined hierarchy, and the one or more transaction signatures prove that relationship; and

wherein the method comprises:

receiving the higher-level contributor transaction; and

determining that the one or more transaction signatures satisfy the one or more signature challenges of the one or more spendable outputs.

2 . The method of claim 1 , wherein the one or more lower-level contributors comprise first and second lower-level contributors, the one or more lower-level contributions comprising first and second lower-level contributions of the first and second lower-level contributors respectively, the one or more lower-level contribution commitments comprising first and second lower-level contribution commitments evidencing the first and second lower-level contributions respectively.

3 . The method of claim 2 , wherein the higher-level contributor transaction contains one or more proofs of receipt of the one or more lower-level contributions, wherein the one or more proofs of receipt comprise:

a first proof of receipt of the first lower-level contribution, and

a second proof of receipt of the second lower-level contribution.

4 . The method of claim 1 , wherein the higher-level contributor transaction contains one or more proofs of receipt of the one or more lower-level contributions.

5 . The method of claim 4 , wherein the one or more proofs of receipt are contained in the one or more inputs and satisfy, respectively, one or more proof-of-receipt challenges of the one or more spendable outputs of the one or more lower-level contributor transactions.

6 . The method of claim 5 , wherein the method further comprises determining that the one or more proofs of receipt satisfy, respectively, the one or more proof-of-receipt challenges.

7 . The method of claim 1 , wherein the higher-level contributor transaction contains a proof-of-receipt challenge for the higher-level contribution.

8 . The method of claim 7 , wherein the proof-of-receipt challenge, the transaction signature challenge for a receiving entity and/or a discretionary signature are contained in one or more outputs of the higher-level contributor transaction.

9 . The method of claim 1 , wherein the higher-level contributor transaction contains a transaction signature challenge for a receiving entity.

10 . The method of claim 1 , wherein the higher-level contributor transaction contains a discretionary signature generated by applying a signature function to a private key of the higher-level contributor and a proof of the higher-level contribution, the proof of the higher-level contribution being the higher level contribution or a hash or other function thereof, wherein the proof of the higher-level contribution is not contained in the higher-level contributor transaction.

11 . The method of claim 1 , wherein the contribution commitments are contribution hashes.

12 . The method of claim 1 , wherein the one or more outputs comprise:

a summary hash computed by hashing a concatenated string comprising a single or multi-hash of the first lower-level contribution and a single or multi-hash of the second lower-level contribution, the spendable output being spendable independently of the summary hash.

13 . A computer-implemented method of processing a blockchain transaction, wherein one or more blockchain transactions are used for recording contributions to a work by contributors having respective levels in a defined hierarchy, in which first and second lower-level contributors provide, to an intermediate-level contributor, first and second lower-level contributions respectively, and the intermediate-level contributor provides, to a higher-level contributor, an intermediate-level contribution responsive to the first and second lower-level contributions, wherein the blockchain transaction comprises:

one or more inputs comprising:

a first proof of receipt of the first lower-level contribution,

a second proof of receipt of the second lower-level contribution, and

a transaction signature of the intermediate-level contributor;

one or more outputs comprising:

a proof-of-receipt challenge for the intermediate-level contribution,

a transaction signature challenge for the higher-level contributor, and

a discretionary signature;

wherein the discretionary signature is generated by applying a signature function to a private key of the intermediate-level contributor and the intermediate-level contribution or a hash thereof; and

wherein at least the proof-of-receipt challenge and the transaction signature challenge are comprised in an output of the one or more outputs, which is spendable independently of the discretionary signature;

wherein the method comprises:

receiving the blockchain transaction; and

verifying the transaction signature of the intermediate-level contributor.

14 . The method of claim 13 , wherein the method further comprises

determining that the first proof of receipt of the first lower-level contribution is valid for a first proof-of-receipt challenge for the first lower-level contribution; and

determining that the second proof of receipt of the second lower-level contribution is valid for a second proof-of-receipt challenge for the second lower-level contribution.

15 . The method of claim 13 , wherein the one or more outputs comprise:

a summary hash computed by hashing a concatenated string comprising a single or multi-hash of the first lower-level contribution and a single or multi-hash of the second lower-level contribution, the spendable output being spendable independently of the summary hash.

16 . The method of claim 15 , wherein the discretionary signature is comprised in the spendable output, the transaction signature challenge being a functional operand of a multi-signature check opcode and the discretionary signature being a dummy operand of the multi-signature check opcode, wherein the summary hash is comprised in the spendable output as a dummy operand of the multi-signature check opcode.

17 . The method of claim 13 , in which a second intermediate-level contributor provides a second intermediate-level contribution to the higher-level contributor;

wherein the one or more inputs of the blockchain transaction further comprise:

a third proof of receipt of a third lower-level contribution,

a transaction signature of the second intermediate-level contributor;

wherein the one or more outputs further comprise:

a proof-of-receipt challenge for the second intermediate-level contribution, and

a second discretionary signature;

wherein at least the challenge for the second intermediate-level contribution is comprised in said spendable output of the one or more outputs or another spendable output of the one or more outputs;

wherein the second discretionary signature is generated by applying a signature function to a single or multi-hash of the second intermediate-level contribution and said private key or another private key of the intermediate-level contributor.

18 . The method of claim 13 , wherein the discretionary signature is comprised in one or more un-spendable outputs of the blockchain transaction.

19 . The method of claim 13 , wherein the discretionary signature is comprised in the spendable output, the transaction signature challenge being a functional operand of a multi-signature check opcode and the discretionary signature being a dummy operand of the multi-signature check opcode.

20 . A non-transitory medium storing instructions, when executed by a processor, that cause the processor to perform a method of recording, in one or more blockchain transactions, contributions to a work by contributors having respective levels in a defined hierarchy, in which one or more lower-level contributors provide, to a higher-level contributor, one or more lower-level contributions respectively, and the higher-level contributor provides a higher-level contribution responsive to one or more lower-level contributions, the method comprising:

at computer equipment of the higher-level contributor, creating or modifying a higher-level contributor transaction to evidence the higher-level contribution, the created or modified higher-level contributor transaction comprising:

one or more inputs comprising:

one or more pointers to one or more spendable outputs of one or more lower-level contributor transactions, the one or more lower-level contributor transactions containing one or more lower-level contribution commitments evidencing the one or more lower-level contributions respectively, and

one or more transaction signatures of the higher-level contributor satisfying one or more signature challenges of the one or more spendable outputs,

wherein the higher-level contributor transaction contains a higher-level contribution commitment computed from the higher-level contribution, wherein the one or more pointers and the contribution commitments represent a relationship between the higher-level contributor and the one or more lower-level contributors within the defined hierarchy, and the one or more transaction signatures prove that relationship.