Blockchain transaction privacy enhancement through broadcast encryption

A computing system comprising:

• a storage configured to store a broadcast encryption tree comprising a set of cryptographic keys arranged in a hierarchical tree structure;
• a network interface configured to distribute a different partially overlapping set of cryptographic keys from the broadcast encryption tree to each respective peer from among a group of peers included in a blockchain network, and to receive, from a user device, an identification of at least two peers included in the group of peers authorized to process a blockchain transaction;
• and
• a processing device configured to select a cryptographic key in the broadcast encryption tree which is shared between different partially overlapping sets of cryptographic keys of the at least two peers and which is not known to remaining peers included in the group of peers;
• wherein the network interface is further configured to transmit information about the selected cryptographic key to the user device to perform broadcast encryption.

A non-transitory computer readable medium having stored therein program instructions that when executed cause a computer to perform a method comprising:

• storing a broadcast encryption tree comprising a set of cryptographic keys arranged in a hierarchical tree structure;
• distributing a different partially overlapping set of cryptographic keys from the broadcast encryption tree to each respective peer among a group of peers included in a blockchain network;
• receiving, from a user device, an identification of at least two peers included in the group of peers authorized for processing a blockchain transaction;
• selecting a cryptographic key in the broadcast encryption tree which is shared between different partially overlapping sets of cryptographic keys of the at least two peers and which is not known to remaining peers included in the group of peers;
• and
• transmitting information about the selected cryptographic key to the user device for performing broadcast encryption.