Visa International Service Association

Ranjit Kumar Kumaresan

Sivanarayana Gaddam

Srinivasan Raghuraman

Rohit Sinha

Mihai Christodorescu

Mahdi Zamani

Mohammad Mohsen Minaei Bidgoli

Arjuna Wijeyekoon

Described are a system and computer program product for secure n-party computation. The system includes a computing device programmed or configured to communicate an input to a trusted execution environment (TEE), and receive a first encrypted output. The computing device is also programmed or configured to post the first encrypted output on a blockchain and receive a first proof of publication. The computing device is further programmed or configured to communicate the first proof of publication to the TEE and receive the first function output of the n-party computation. The computing device is further programmed or configured to communicate a witness to the TEE and receive a second encrypted output. The computing device is further programmed or configured to post the second encrypted output on the blockchain, receive a second proof of publication, communicate the second proof of publication to the TEE, and receive the second function output.

System and computer program product for fair, secure n-party computation using at least one blockchain

A method includes a first user device generating an interaction message. The interaction message includes an amount, an expiry time, and a condition. The first user device provides the interaction message to a second user device. The second user device creates a witness that satisfies the condition and provides the witness to the first user device. The first user device receives the witness from the second user device. The first user device verifies that the witness satisfies the condition. If the witness satisfies the condition and is received prior to the expiry time, the first user device signs the witness using a first user device private key to obtain a signed witness. The first user device provides the signed witness to the second user device. The second user device verifies a signature of the signed witness and proceeds with obtaining the amount.

Conditional offline interaction system and method

Described are a system, method, and computer program product for secure real-time n-party computation. The method includes receiving a first computation input and a first portion of a one-time key from a first computer device, and receiving a second computation input and a second portion of the one-time key from a second computer device. The method also includes generating the one-time key based on the first and second portion of the one-time key, and executing a computation based on the first and second computation input. The method further includes generating an encrypted output by encrypting the computation with the one-time key, and communicating the encrypted output to the first computer device. The method further includes receiving a proof of publication from the first computer device and, in response to receiving the proof of publication, communicating the one-time key to the first computer device.

System, method, and computer program product for secure real-time N-party computation

Systems and methods for transferring value. A method includes posting, by a user device to a blockchain, a deposit transaction comprising a deposit value and conditions and updating, by the user device, a state according to a transaction amount. The method also includes transmitting, by the user device, a state update of the state to a server computer and responsive to transmitting the state update, and receiving, by the user device, a payment complete message comprising a tuple from the server computer. The method also includes verifying, by the user device, the conditions and processing, by the user device, a server deposit transaction on the blockchain in response to verifying.

Universal payment channels

Described herein are a system and techniques for enabling user control over usage of their information by data consumers, even when untrusted parties are involved, while also preventing collusion between the untrusted party and a data consumer. A user's information may be collected by a client device and provided to a host server. An encrypted version of the user's information may be stored at the host server so that it is processed on a private enclave of the host server. When the data is to be provided to multiple data consumers, the data may be encrypted for each of the data consumers and may be released to each of those data consumers simultaneously once confirmation has been received that the data has been made available to each of the data consumers.

Techniques for preventing collusion using simultaneous key release

Described are a system and method for secure n-party computation. The method includes communicating a first input of an n-party computation to a trusted execution environment (TEE). The method also includes receiving, from the TEE, at least one encrypted output of the n-party computation using the first input and at least one second input of at least one other computing device, and using at least one public key of the at least one other computing device. The method further includes posting the at least one encrypted output on at least one blockchain accessible by the at least one other computing device. The method further includes, in response to posting the at least one encrypted output, receiving at least one proof of publication. The method further includes communicating the at least one proof of publication to the TEE and receiving the function output of the n-party computation.

System and method for fair, secure n-party computation using at least one blockchain

Described are a system, method, and computer program product for secure real-time n-party computation. The method includes communicating, to a trusted execution environment (TEE), a first computation input and a first portion of a one-time key. The method also includes receiving, from the TEE, an encrypted output of a computation based on the first computation input and a second computation input communicated to the TEE by a second computing device. The method further includes communicating the encrypted output to the second computing device and receiving a digital signature indicating that the second computing device received the encrypted output. The method further includes communicating the first portion of the one-time key to the second computing device and, in response to not receiving the second portion of the one-time key from the second computing device, executing a fallback computation process using the TEE and a shared ledger to determine the computation.

System, method, and computer program product for secure real-time n-party computation

Methods and systems for secure multi-party generation of random bits are disclosed. These random bits can be generated securely, even if some parties (i.e., less than a corruption threshold) are dishonest or malicious. Methods and systems can use secure environments in order to securely generate and store cryptographic keys. Using broadcast protocols such as Dolev-Strong, a generator computer can distribute a public protocol instance key to other participant computers. Each participant computer can generate a random bit and encrypted the random bit with the public protocol instance key, and broadcast its encrypted random bit to the other participant computers. Once each participant computer has received the encrypted random bits from all other participant computers, the private protocol instance key can be released to the participant computers, enabling the participant computers to decrypt the encrypted random bits, and calculate an output random bit based on the encrypted random bits.

Growing community of inventors

Sunnyvale, CA, United States of America

Ranjit Kumar Kumaresan