International Business Machines Corporation

Yacov Manevich

Artem Barger

Hagar Meir

Nitin Gaur

Petr Novotny

Elli Androulaki

Angelo De Caro

Alessandro Sorniotti

Yoav Tock

Dulce Beatriz Ponceleon

Marko Vukolić

Jason Karl Yellick

Sarbajit Kumar Rakshit

Kaoutar El Khiyaoui

Marcus Brandenburger

Corville O Allen

Yada Zhu

Jonathan Bnayahu

Guy Laden

Senthilnathan Natarajan

Alexander Kofman

Nir Rozenbaum

Pratul Gupta

A processor may store a write set of a transaction in a cache. The cache may include state information, and the cache may be uncommitted to a blockchain. The processor may identify a subsequent transaction. The subsequent transaction may read from the cache when a requested key is present in the cache. The processor may order the transaction and the subsequent transaction based on what is read from the cache. Ordering the transaction and the subsequent transaction may avoid an abort of the subsequent transaction.

Reducing transaction aborts in execute-order-validate blockchain models

An example operation may include one or more of receiving a blockchain transaction that includes a proposed transfer of a token from a sender to a recipient, verifying that the transfer of the token is certified by a blockchain network based on a zero-knowledge proof (ZKP) included in the blockchain transaction and a signed token commitment stored on a blockchain ledger of the blockchain network, and committing the blockchain transaction to a block on the blockchain ledger of the blockchain network in response to verification of the transfer of the token.

Non-interactive token certification and verification

An example operation may include one or more of transmitting a user identifier to a plurality of blockchain peers of a blockchain network, receiving a plurality of public keys from the plurality of blockchain peers, receiving a plurality of ciphertexts from the plurality of blockchain peers generated based on the user identifier and a corresponding plurality of private keys, generating a combined ciphertext that includes the plurality of ciphertexts and generating a temporary blockchain address of the blockchain network based on the plurality of public keys, and storing the combined ciphertext and a transfer of an asset via the temporary blockchain address of the blockchain network.

Future asset reclamation via blockchain

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.

Privacy preserving asset token exchange

An example operation may include one or more of encrypting a private key with an encryption key, generating a plurality of keys based on the encryption key and converting the plurality of keys into a plurality of key shares based on a secret input value, storing the encrypted private key on a blockchain, and distributing the plurality of key shares to a plurality of blockchain peers of the blockchain, where the distributing comprises transmitting a different key share from among the plurality of key shares to each blockchain peer among the plurality of blockchain peers.

Key reclamation in blockchain network via OPRF

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.

Transaction reordering in blockchain

An operator for a global total order broadcast domain may send an operation out of band to nodes of participating parties, receive a certificate and a signature on an operation identifier for each participating node, generate a randomness vectors for each party participating in the operation, generate a random symmetric encryption key, encrypt the certificates, the signatures, and the randomness vector for each participating party with the symmetric encryption key, encrypt the symmetric encryption key under each public key for each participating party, and hash the symmetric encryption key, and recording, by the operator, the hashed symmetric encryption key on the global total order broadcast domain.

Anonymous private shared partitions in a global total order broadcast domain networks using random symmetric encryption keys

An example operation may include one or more of receiving, via a custodial service, a request to transact with a digital asset owned by a user and temporarily in custody of the custodial service, generating a blockchain transaction comprising an identifier of the digital asset on a blockchain ledger, an identifier of the custodial service, and an identifier of a recipient of the digital asset, signing the blockchain transaction with a key from a trifocal key which proves that the custodial service is authorized to transact with the digital asset on behalf of the user, and storing the signed blockchain transaction on a blockchain ledger.

Trifocal key for controlling custodians of digital assets

A node in a blockchain network may receive an event initiation for a first digital corollary of a first physical asset, receive conditional data related to the first digital corollary, detecting, by the node, a link to a second digital corollary, prompt a simulation of the second digital corollary, receive an outcome of the simulation, and determine an executable action for the second digital corollary.

Glue-contracts for digital corollaries in blockchain networks

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.

Redactable blockchain

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.

Blockchain with random committee selection

An example operation may include one or more of a computer generating an output of a variable random function applied to a public key of a user of a blockchain and a hash of the blockchain block, the computer determining a function f that gives a number x in [0,1] to each of a plurality of transactions on the block based on the output, and the computer ordering the transactions, using the function f, within the block.

Fair transaction ordering in blockchains

A node in a blockchain network may generate a key for a first ring, wherein the key unlocks a first collection of data, defining a second ring including a second node of a second organization, derive a second key for a second collection of data, wherein the first key and the second key access the second collection of data, and distributing the second key to the second node.

Blockchain data segregation

A processor may segment a media key block into two or more subsets. Each of the two or more subsets may be respectively associated with a particular group of receivers, and each receiver of the particular group of receivers may be in a blockchain network. The processor may receive, from a first receiver, a request for permission to process the media key block. The processor may identify which of the two or more subsets that the first receiver is associated. The processor may provide a media key block value to the first receiver.

Decentralized, dynamic media key block for broadcast encryption

An operator for a global total order broadcast domain executing a method to send an operation out of band to nodes of participating parties in a partition, receive a certificate and a signature on the operation for each of the participating parties, generate a single party packet based on the received signatures, generate a random symmetric encryption key, send the random symmetric encryption key to the participating parties, encrypt the single party packet with the random symmetric encryption key, generate a pseudo random string for the partition, and record an operation identifier, the encrypted party packet, and the pseudo random string on the global total order broadcast domain.

Growing community of inventors

Haifa, Israel

Yacov Manevich