Generating digital signature shares
AssigneenChain Licensing AG
InventorMichaella PETTIT
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Abstract
A computer-implemented method of generating a respective signature share of a digital signature for signing a message, wherein the method is performed by a first participant of the group and comprises: obtaining at least the threshold number of respective participant indexes, wherein the obtained respective participant indexes comprises a first participant index associated with the first participant; generating a private key index, wherein the private key index is generated based on a hash of a combination of the obtained respective participant indexes; generating a second common private key of the first hierarchical key structure; and generating a first signature share of the digital signature.
Claims12
A computer-implemented method of generating a digital signature for signing a message, wherein each participant of a group of participants has i) a respective private key share of a shared private key, wherein the shared private key can only be generated with at least a threshold number of respective private key shares, ii) a respective ephemeral private key share of a shared ephemeral private key, iii) a first co-ordinate of an ephemeral public key corresponding to the shared ephemeral private key, and iv) a first common private key of a first hierarchical key structure, wherein each participant is associated with a respective participant index, and wherein the method is performed by a coordinating party and comprises:
- obtaining, from respective participants, at least the threshold number of respective signature shares of the digital signature, each respective signature share associated with a respective participant and derived based on a respective ephemeral key share of the shared ephemeral private key, the message, a second common private key of the first hierarchical key structure, the first co-ordinate of the ephemeral public key, and a respective private key share of the shared private key, the second common private key based on the first common private key and a first hash value based on a hash of at least a) the first common private key or a corresponding public key, and b) a private key index derived based on a hash of a combination of at least the threshold number of respective participant indexes;
- generating the digital signature based on at least the obtained threshold number of respective signature shares.
Computer equipment comprising:
- memory comprising one or more memory units;
- and
- processing apparatus comprising one or more processing units, wherein the memory stores code arranged to run on the processing apparatus, the code being configured so as when run on the processing apparatus the processing apparatus is configured to perform a method of generating a digital signature for signing a message, wherein each participant of a group of participants has i) a respective private key share of a shared private key, wherein the shared private key can only be generated with at least a threshold number of respective private key shares, ii) a respective ephemeral private key share of a shared ephemeral private key, iii) a first co-ordinate of an ephemeral public key corresponding to the shared ephemeral private key, and iv) a first common private key of a first hierarchical key structure, wherein each participant is associated with a respective participant index, and wherein the method is performed by a coordinating party and comprises:
- obtaining, from respective participants, at least the threshold number of respective signature shares of the digital signature, each respective signature share associated with a respective participant and derived based on a respective ephemeral key share of the shared ephemeral private key, the message, a second common private key of the first hierarchical key structure, the first co-ordinate of the ephemeral public key, and a respective private key share of the shared private key, the second common private key based on the first common private key and a first hash value based on at least a) the first common private key or a corresponding public key, and b) a private key index derived based on a hash of a combination of at least the threshold number of respective participant indexes;
- generating the digital signature based on at least the obtained threshold number of respective signature shares.
A computer program embodied on non-transitory computer-readable storage media and configured so as, when run on one or more processors, to perform a method of generating a digital signature for signing a message, wherein each participant of a group of participants has i) a respective private key share of a shared private key, wherein the shared private key can only be generated with at least a threshold number of respective private key shares, ii) a respective ephemeral private key share of a shared ephemeral private key, iii) a first co-ordinate of an ephemeral public key corresponding to the shared ephemeral private key, and iv) a first common private key of a first hierarchical key structure, wherein each participant is associated with a respective participant index, and wherein the method is performed by a coordinating party and comprises:
- obtaining, from respective participants, at least the threshold number of respective signature shares of the digital signature, each respective signature share associated with a respective participant and derived based on a respective ephemeral key share of the shared ephemeral private key, the message, a second common private key of the first hierarchical key structure, the first co-ordinate of the ephemeral public key, and a respective private key share of the shared private key, the second common private key based on the first common private key and a first hash value based on at least a) the first common private key or a corresponding public key, and b) a private key index derived based on a hash of a combination of at least the threshold number of respective participant indexes;
- generating the digital signature based on at least the obtained threshold number of respective signature shares.
Dependencies are inferred from the claim text.