Nec Corporation

Kari Kostiainen

Ghassan Karame

Srdjan Capkun

Sinisa Matetic

Moritz Schneider

Karl Wuest

Sven Gnap

A blockchain payment involves a transfer of funds from an account of a user to a collateral account of a service provider. The service provider receives a payment intent from the user including a payment index, a random payment ID, and an address of the collateral account. The service provider replaces the address by a commitment and provides the modified payment intent to a majority of statekeepers of a blockchain, receives payment approvals from the statekeepers, each payment approval including the modified payment intent signed with a private key of a respective statekeeper, evaluates the received payment approvals, aggregates successfully evaluated payment approvals, and transmits the aggregation result to the user. The service provider receives a final transaction created by the user after having verified the aggregation result, verifies that the user correctly constructed the final transaction, and accepts the payment in case of successful verification of the final transaction.

Fast blockchain payment method and system

A method of preserving privacy for usage of a lightweight blockchain client in a blockchain network includes using, in a full blockchain node of the blockchain network, a trusted execution environment (TEE). A secure communication is established between the lightweight blockchain client and the TEE. The TEE receives a request from the lightweight blockchain client for at least one transaction or address of the lightweight blockchain client. The TEE obtains unspent transaction output (UTXO) information with respect to the request from the lightweight blockchain client from a UTXO database by oblivious database access using an oblivious RAM (ORAM) protocol.

Method and system of preserving privacy for usage of lightweight blockchain clients

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Zurich, Switzerland

Kari Kostiainen