Abstract: Recursive endorsements in a decentralized database minimize validation effort for a smart contract because there are fewer signatures to verify. Collected endorsements required by an endorsement policy are verified and signed by a set of trusted peers representing different organizations, the set of trusted peers being fewer than the number of endorsing peers. Prior to validation, the target transaction is submitted with all required endorsements and the signatures of the set of trusted peers. Validation is performed by verifying only the signatures of the set of trusted peers.

Abstract: An example operation includes one or more of generating, by a channel peer, a random value to be associated with a channel name, mapping, by the channel peer, the random value to a block range, receiving, by the channel peer, a channel-MAC from a second peer, and validating the channel-MAC based on the channel name and the random value.

Abstract: An example operation includes one or more of receiving view change messages which request a view change from a previous primary peer of a blockchain to the primary peer, identifying that a change to a state of the blockchain is in process with the previous primary peer based on metadata of the received view change messages, verifying that the change to the state of the blockchain corresponds to a latest change to the blockchain based on a received view data message, and transmitting a new view message to following peers which includes the in-process change to the state of the blockchain.

Abstract: An example operation includes one or more of receiving view change messages which request a view change from a previous primary peer of a blockchain to the primary peer, identifying that a change to a state of the blockchain is in process with the previous primary peer based on metadata of the received view change messages, verifying that the change to the state of the blockchain corresponds to a latest change to the blockchain based on a received view data message, and transmitting a new view message to following peers which includes the in-process change to the state of the blockchain.

Abstract: A computer-implemented system and method process a private transaction for dividing a blockchain transaction into a plurality of requests. Each of the requests have transaction data and a same transaction identifier. Each request is sent to a respective participating shard of a set of participating shards in the blockchain transaction of the blockchain. A response to the request is received from each participating shard, and each of the responses is sent to at least the participating shards except the shard the response was received from. In an atomic commit operation, a prepare transaction is created comprising information from the responses and the transaction identifier. The prepare transaction is submitted to the blockchain, and validity answers are received from the shards.

Abstract: A method for providing privacy-preserving asset transfers between networks, by connecting to a first blockchain network, receiving login data from a user, receiving an asset pledge transaction for an asset, confirming that the user is an owner of the asset based on a previous asset transfer transaction associated with the user, verifying an availability of the asset based on first blockchain network records, determining that a recipient is a registered user of a second blockchain network, assigning the asset to a first unique identifier, receiving at least one of a pledge proof request, from the recipient prior to expiration of the deadline, and an asset reclaim transaction, from the user after expiration of the deadline, the pledge proof request and reclaim transaction each comprising the first unique identifier and responding to the at least one of the pledge proof request and the asset reclaim request according to the deadline.

Abstract: A method for documenting asset exchanges between users by connecting to a first blockchain network configured to store user assets, receiving login data from a first user, receiving an asset lock transaction for an asset from the first user, confirming that the first user is an owner of the asset based on a previous asset transfer transaction associated with the user, verifying availability of the asset based on blockchain network records, determining that the second user is a registered user of the blockchain network, assigning the asset to a unique identifier of the asset lock transaction, receiving at least one of a claim request from the second user, prior to expiration of the deadline, and a reclaim transaction from the user following expiration of the deadline, and responding to the at least one of the claim request and the reclaim request according to the deadline.

Abstract: An example operation may include one or more of storing blockchain blocks committed to a blockchain based on a protocol executed by a current consensus committee of a blockchain network, receiving random values from the blockchain blocks which are created by nodes of the current consensus committee, randomly determining nodes of a next consensus committee of the blockchain network with respect to the current consensus committee based on the random values created by the nodes of the current consensus committee, and storing a new block to the blockchain based on a protocol based executed by the nodes of the next consensus committee.

Abstract: An example operation may include one or more of retrieving a block hash of a data block stored on a blockchain, randomly determining a subset of peer organizations from a blockchain network of the blockchain to be endorsers based on a value of the block hash, transmitting a blockchain storage request from a client to the randomly determined subset of endorser peer organizations, and collecting simulated responses from the randomly determined subset of endorser peer organizations into a storage request proposal.

Abstract: An example operation may include one or more of storing a list of unavailable blockchain peers that cannot be a lead peer of a blockchain consensus protocol, generating a pre-prepare message comprising a new block of a blockchain, appending commit messages received during a commit stage of a previous block to the blockchain, to the pre-prepare message, where the commit messages identify an unavailable blockchain peer from the list that is now available, and broadcasting the pre-prepare message with the new block and the appended commit messages to a plurality of blockchain peers.

Abstract: An example operation includes one or more of receiving view change messages which request a view change from a previous primary peer of a blockchain to the primary peer, identifying that a change to a state of the blockchain is in process with the previous primary peer based on metadata of the received view change messages, verifying that the change to the state of the blockchain corresponds to a latest change to the blockchain based on a received view data message, and transmitting a new view message to following peers which includes the in-process change to the state of the blockchain.

Abstract: A processor may endorse the group of transactions received from one or more clients. The processor may provide a read-set and a write-set for each transaction of the group of transactions. The processor may order the group of transactions at an ordering service. The ordering service may have a group of orderers and may order the group of transactions. The order of the transactions may be based on the read-set and the write-set of each transaction. The processor may commit the group of transactions to the blockchain.

Abstract: In some embodiments, a processor may store a value and a hash of the value in a ledger associated with a blockchain network. The processor may construct a block hash from the hash of the value. The processor may validate a transaction by identifying that the hash of the value matches the hash of the value from a previous transaction. The processor may maintain integrity of the block hash. In some embodiments, a processor may provide a redact transaction for a blockchain network. The processor may initialize the redact transaction. The redact transaction may be associated with a validated transaction. The processor may identify a hash value indicated within the redact transaction and associated with the validated transaction. The processor may redact a value associated with the hash value.

Abstract: An example operation includes one or more of receiving view change messages which request a view change from a previous primary peer of a blockchain to the primary peer, identifying that a change to a state of the blockchain is in process with the previous primary peer based on metadata of the received view change messages, verifying that the change to the state of the blockchain corresponds to a latest change to the blockchain based on a received view data message, and transmitting a new view message to following peers which includes the in-process change to the state of the blockchain.

Abstract: A computer-implemented system and method process a private transaction for dividing a blockchain transaction into a plurality of requests. Each of the requests have transaction data and a same transaction identifier. Each request is sent to a respective participating shard of a set of participating shards in the blockchain transaction of the blockchain. A response to the request is received from each participating shard, and each of the responses is sent to at least the participating shards except the shard the response was received from. In an atomic commit operation, a prepare transaction is created comprising information from the responses and the transaction identifier. The prepare transaction is submitted to the blockchain, and validity answers are received from the shards.

Abstract: An example operation includes one or more of receiving view change messages which request a view change from a previous primary peer of a blockchain to the primary peer, identifying that a change to a state of the blockchain is in process with the previous primary peer based on metadata of the received view change messages, verifying that the change to the state of the blockchain corresponds to a latest change to the blockchain based on a received view data message, and transmitting a new view message to following peers which includes the in-process change to the state of the blockchain.

Abstract: An example operation includes one or more of generating, by a channel peer, a random value to be associated with a channel name, mapping, by the channel peer, the random value to a block range, receiving, by the channel peer, a channel-MAC from a second peer, and validating the channel-MAC based on the channel name and the random value.

Abstract: An example operation may include one or more of retrieving a block hash of a data block stored on a blockchain, randomly determining a subset of peer organizations from a blockchain network of the blockchain to be endorsers based on a value of the block hash, transmitting a blockchain storage request from a client to the randomly determined subset of endorser peer organizations, and collecting simulated responses from the randomly determined subset of endorser peer organizations into a storage request proposal.

Abstract: Methods, systems, and programming for accessing data are described herein. In a non-limiting embodiment, a request associated with a key may be received. A memory chunk in a first memory site associated with the key may be located. An entry in the memory chunk corresponding to the key may be determined. A first pointer to the key corresponding to a first location of the key within a buffer at a second memory site may be obtained from the entry. The key stored at the first location may be retrieved from the buffer at the second memory site.

Abstract: Methods, systems, and programming for accessing data are described herein. In a non-limiting embodiment, a request associated with a key may be received. A memory chunk in a first memory site associated with the key may be located. An entry in the memory chunk corresponding to the key may be determined. A first pointer to the key corresponding to a first location of the key within a buffer at a second memory site may be obtained from the entry. The key stored at the first location may be retrieved from the buffer at the second memory site.