International Business Machines Corporation

Angelo De Caro

Elli Androulaki

Alessandro Sorniotti

Yacov Manevich

Kaoutar El Khiyaoui

Artem Barger

Venkatraman Ramakrishna

Marko Vukolić

Jan Leonard Camenisch

Emanuele Ragnoli

Thorsten Kramp

Senthilnathan Natarajan

Jason Karl Yellick

Yu Chin Fabian Lim

Shengjiao Cao

Fabian Portmann

Kaoutar Elkhiyaoui

Jens Jelitto

Tamas Visegrady

David W Kravitz

Krishnasuri Narayanam

Gregory Neven

Vinayaka D Pandit

Yuan Yuan

Ermyas Abebe

Yohei Ueda

Maria Dubovitskaya

Hagar Meir

Dhinakaran Vinayagamurthy

Yanyan Hu

Matthias Neugschwandtner

Chun Hui Suen

Esha Ghosh

Ilie Circiumaru

Christian Gorenflo

Yining Hu

A system and method for a multi-party computation (MPC) is provided. In implementations, a method includes identifying a blockchain network and a computing device to perform an MPC based on an index; generating an MPC request including a function to be performed by the blockchain network and the computing device, data required for the function, and a verification policy defining a verification protocol to be performed by the blockchain network and the computing device; sending the MPC request to the blockchain network and the computing device; and receiving responses from a representative computing node of the blockchain network and the computing device, wherein each of the responses includes: an output of an MPC protocol performed by the blockchain network and the computing device to jointly compute the function while keeping the inputs private from one another and private from the computing system; and a proof based on the verification policy.

Collaborative computation across blockchain networks

A user of a blockchain network may obtain credentials for the user from an issuer, the credentials based on one or more attributes of the user, wherein the issuer is selected from one or more authorized issuers, and wherein the credentials include a signature on the one or more attributes and a secret key; generate an operation composed of a payload and a second signature; compute a commitment to a public key of the issuer; prove, using a one-out-of-many proof, that the commitment is a valid commitment to a public key of one of the authorized issuers; prove, using a zero-knowledge proof, proof of knowledge of the signature and the credentials under the public key of the issuer; and prove, using a proof of knowledge, of values of the signed secret key and attributes.

Multi-issuer anonymous credentials for permissioned blockchains

The present disclosure relates to storing a set of n data entries. The method includes creating a tree of ary l such that n leaf nodes of the tree comprise a set of hash values of the set of data entries respectively. For each parent node of the tree, a bilinear accumulator of hash values of l children of the parent node may be computed. A hash value of the bilinear accumulator may be computed. The root node of the tree may be stored as a representation of the content of the set of data entries.

Storing data in a tree using bilinear accumulation

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 includes one or more of receiving event data from an entity, determining the event data satisfies an endorsement policy, setting an identifier that corresponds to a context of the event data, generating an event which includes the event data and the identifier, and submitting the event for recording in a decentralized database, wherein the identifier is used to validate that a state corresponding to the context in the event data is correct.

Pre-validated event processing in a decentralized database

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 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.

Private ledger partitions in blockchain networks

An example operation may include one or more of receiving, by each of one or more peripheral peers of a blockchain network, a new block from an orderer peer, calculating a hash of the new block, determining the calculated hash is different than hashes from a majority of peripheral peers, determining that one or more blocks that correspond to the different hashes from the majority of peripheral peers are different from the new block, and in response ceasing committing blocks to the blockchain network.

Malicious peer identification

An example operation may include one or more of receiving, by each of one or more peripheral peers of a blockchain network, a sequence of new blocks from an orderer peer, calculating hashes for the sequence of new blocks, adding the hashes to a merkle tree, determining the merkle tree is different than merkle trees from a majority of peripheral peers, determining that one or more blocks that correspond to the different merkle trees from the majority of peripheral peers are different from the sequence of new blocks, and in response ceasing committing blocks to the blockchain network.

Malicious peer identification for database block sequence

In some embodiments, a processor may generate a request associated with a transaction, collect an anchor associated with the request, and transition the transaction into a collection of two or more hashes; the processor may submit the transaction to an ordering service. In some embodiments, a processor may receive a request associated with a transaction, identify that a first preimage associated with a first hash is known to a first shard, and generate a first identification tag associated with the transaction. In some embodiments, a processor may receive a request associated with a transaction, assign a first shard a first task, and identify that a first preimage associated with a first hash is known to the first shard; the processor may perform the task.

Privacy preserving architecture for permissioned blockchains

An example operation may include one or more of receiving an event from a node, extracting an identifier from the event, determining whether the event is authorized, and generating a notification of the event when the identifier is authorized, wherein the identifier includes a hashed value of an event counter and wherein the identifier is authorized when the hashed value matches a hashed value of the event counter stored in a storage area of or coupled to the client.

Information management in a database

An example operation may include one or more of identifying a new entry, receiving one or more new entry signatures to approve the new entry to, such that the one or more new entry signatures each include a signature of the new entry and hashes of previously signed entries for a common block, verifying the one or more new entry signatures for commit by performing a signature verification of the new entry, determining the common block has more than one entry with a hash signed by a same member, and responsive to the signature check being performed on the new entry and determining the common block has more than one entry with a hash signed by a same member, designating one or more previously received entries as verified for commit without performing a signature verification of the one or more previously received entries.

Reducing signature verifications of database entries

An example operation may include one or more of creating a shared secret via a blockchain node member, storing the shared secret in a memory outside the blockchain, and sharing the shared secret with one or more other blockchain node members during a setup phase of an execution environment associated with a chaincode.

Authenticating chaincode to chaincode invocations of a blockchain

An example operation may include one or more of receiving a request to create a second blockchain in a network that includes a first blockchain, sending a message to one or more validating peer nodes in the network, the one or more validating peer nodes corresponding to a subset of validating peer nodes of the network that have access to the first blockchain, the message requesting authorization for the second blockchain, analyzing responses to the message from the subset of validating peer nodes, and authorizing creation of the second blockchain based on the analyzed responses.

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Zurich, Switzerland

Angelo De Caro