International Business Machines Corporation

Kaoutar El Khiyaoui

Elli Androulaki

Angelo De Caro

Yacov Manevich

Alessandro Sorniotti

Hagar Meir

Christian Gorenflo

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

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

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 approach for privacy-preserving auditable accounts on blockchain networks. The approach may include encoding tokens associated with a blockchain network. The encoding may include data relating to the current epoch, where an epoch is a specific time range. The tokens may be received from a user for inspection by an auditing entity. The approach may include performing an audit check on the encoded tokens. If the audit check succeeds, the auditing entity may submit an audit transaction verifying the tokens were generated in the current epoch and making the tokens auditable for the next epoch.

Privacy preserving auditable accounts

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.

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Zurich, Switzerland

Kaoutar El Khiyaoui