International Business Machines Corporation

Andres Garagiola

Jeronimo Irazabal

Dulce Beatriz Ponceleon

Diego A Masini

Guillermo R Lopez

Raul Laprida

John B Geagan, Iii

Luis Angel D Bathen

Pawan Raghunath Chowdhary

David W Kravitz

Darryl Maurice Adderly

Shun Jiang

Kevin Lavern Schultz

Chung-hao Tan

Guangjie Ren

Rosanna Mannan

Guillermo Romero Lopez

An example operation may include one or more of executing, by an endorser node, a smart contract to generate a blockchain transaction data, generating, by the endorser node, metadata specific to the endorser node, concatenating, by the endorser node, the metadata with the blockchain transaction data, signing, by the endorser node, a concatenation result data with a key of the endorser node, and providing, by the endorser node, the signed concatenation result data to a committer node for verification.

Metadata-based endorsement

An example operation may include one or more of storing chaincode that comprises a plurality of statements to be executed, receiving a message to endorse a blockchain storage request, delaying execution of one or more statements within the chaincode based on content included within the chaincode, endorsing the blockchain storage request via execution of remaining statements included in the chaincode which are not delayed to generate an endorsement result, and transmitting the endorsement result to a node.

Optimization of chaincode statements

An example operation may include one or more of storing a data block that is included within a sequential chain of data blocks and which comprises a probabilistic data structure stored therein, receiving a request to verify another data block, determining whether a probabilistic hash of the other data block is included within the probabilistic data structure of the stored data block, and in response to a determination that the hash of the other data block is included within the probabilistic data structure, storing an indicator that the other data block is included within the sequential chain of data blocks.

Probabilistic verification of linked data

An example operation may include one or more of storing a broadcast encryption tree comprising a set of cryptographic keys disposed in a hierarchical tree format, distributing a partial set of keys from the broadcast encryption tree to each respective peer from among a group of peers included in a blockchain network, receiving, from a user device, an identification of at least one peer included in the group of peers for processing a blockchain transaction, selecting a subset of keys from among the set of cryptographic keys in the broadcast encryption tree which enables at least one peer to decrypt transactions and doesn't enable the remaining peers included in the group of peers to decrypt transactions, and transmitting broadcast encryption information about the selected subset of keys to the user device for performing encryption of the transactions.

Blockchain transaction privacy enhancement through broadcast encryption

An example operation may include one or more of sending a transmission process from a client with an application, the application coupled to the client, receiving the transmission process from the client via a multistate peer network, the multistate peer network includes a ledger, an endorsement policy, and a smart contract, generating, from the transmission process, a multistate endorsement based ledger process, establishing a threshold state logic and a final state logic via the smart contract, the threshold state logic is set by the minimum number of endorsements required to commit to the ledger set by the endorsement policy, a commitment to the ledger triggers the final state logic, and executing post-settlement processes via the final state logic.

Post-settlement processes

An example operation may include one or more of identifying a new member (M) to a permissioned database, creating a new group including the new member and one or more previously identified members (MP), modifying a world state of the permissioned database to identify a set of members in the new group with access to the permissioned database, and responsive to the new member (M) being identified, creating a new entry (TX) to the permissioned database using an encryption key (K) associated with the new member (M).

Membership access management of a database

An example operation may include one or more of identifying a blockchain transaction, storing the blockchain transaction in a blockchain, assigning the blockchain transaction a transaction number and a block number, hashing a portion of blockchain transaction data associated with the blockchain transaction, and updating a blockchain index based on the hashed portion of the blockchain transaction.

Optimizing queries and other retrieve operations in a blockchain

An example operation may include one or more of a method for providing a one-step transaction submission in a blockchain network, comprising sending a transaction proposal, by a client node, to one or more peers of a plurality of peers, simulating a transaction associated with the transaction proposal, by at least one peer of the plurality of peers, evaluating, by an endorser peer, whether an endorsement policy has been fulfilled, and when the endorsement policy has been fulfilled, sending the transaction to at least one orderer node to be committed to a ledger, by the endorser peer.

Autocommit transaction management in a blockchain network

An example operation may include one or more of obtaining a machine-readable code from a first document among a set of documents, extracting a probabilistic data structure from the machine-readable code which includes probabilistic hashes accumulated from the set of documents, determining whether a document hash of a second document is included within the probabilistic data structure, and in response to a determination that the document hash is included within the probabilistic data structure, outputting a notification indicating the second document is included in the set of documents.

Offline verification with document filter

An example operation may include one or more of receiving, by a committer node or peer of a blockchain network, a block comprising a lock request that locks a partial state of a smart contract, the lock request comprising a submitter identifier and a lock delay, the committer node or peer configured to process blocks of transactions, the method further comprising, validating the lock request, committing transactions comprising the submitter identifier with no delay, and committing transactions not comprising the submitter identifier after the lock delay.

Database transaction guaranteed commitment

An example operation may include one or more of connecting, by a recipient node, to a blockchain network configured to store links to digital assets of an owner, selecting, by the recipient node, an asset from a ledger of the owner, executing, by the recipient node, a smart contract to determine a time frame of the asset use, executing, by the recipient node, a smart contract to download the asset to the recipient node, checking, by the recipient node, if the asset is downloaded successfully, and in response to the successful download of the asset, executing, by the recipient node, a smart contract to log an asset transfer transaction onto the blockchain.

Management of digital assets

An example operation may include one or more of receiving, by a broadcast server node, data from a plurality of data provider nodes; and executing, by the broadcast server node, a smart contract to: encrypt the data with encryption keys; generate a broadcast queue based on the encrypted data; and assign a subset of consumer nodes authorized to receive the encrypted data of the broadcast queue.

Immutable broadcasting queues

An example operation may include one or more of identifying a first conferred asset exchange request from a first user account and a second conferred asset exchange request from a second user account which are capable of being used to settle each other, requesting an intermediary blockchain to perform a conferred asset settlement transaction for the first and second conferred asset exchange requests, determining that first conferred assets of the first user account and second conferred assets of the second user account have been transferred to temporary intermediary trading addresses, respectively, and releasing the first conferred assets to the second user account and the second loyalty assets to the first user account, in response to the determining.

Intermediate blockchain system for managing transactions

An example operation may include one or more of connecting, by a clock node, to a blockchain network comprised of a plurality of nodes, retrieving, by the clock node, a timestamp (Ts) of the clock node, acquiring, by the clock node, a time window (Tw) based on the Ts, reading, by the clock node, a current window (Cw) from a world state, determining, by the clock node, a gap as a difference between the Tw and the Cw, calculating, by the clock node, a clock fix value based on the gap, and adjusting a clock by a subtraction of the clock fix value from the Ts.

Distributed clock

An example operation may include one or more of receiving a request for performing a post-commit validation of a chain of blocks on a distributed ledger, the chain of blocks being encrypted using an encryption key, requesting cooperation from one or more auditor nodes associated with the distributed ledger, each auditor node comprising a partial secret of a decryption key corresponding to the encryption key, and, in response to receiving partial secrets from a minimum threshold of auditor nodes, recovering the decryption key based on the received partial secrets, decrypting the chain of blocks based on the recovered decryption key, and validating content included within the chain of blocks.

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Buenos Aires, Argentina

Andres Garagiola