A method and a system for using differential privacy techniques to provide axe obfuscation with respect to information included in an inventory axe list of available securities is provided. The method includes: obtaining first information to be included in a first inventory axe list to be published on a particular day; retrieving second information included in a second inventory axe list that was published on the previous day and/or several previous days; obfuscating the obtained first information by applying an algorithm based on the difference between the first information and the second information; and publishing the first inventory axe list by transmitting the obfuscated first information to a plurality of intended recipients. The quality of obfuscation may be measured and controlled as a function of desired privacy level and potential cost.

An in-application content transfer system that generates receiver IDs to categorize a given exchange between two users where one does not execute a local instance of the application. One user executes the application on their mobile device and makes use of near-field communication protocols with a neighboring mobile device that is not executing the subject application. The content transfer is linked to the receiver's phone number and a unique ID is assigned to the content transfer. The receiving user is made aware of the content transfer via a push notification received via near field communication or via an SMS text message. The received message or notification enables the user to retrieve the content from the transfer at a later time.

An online system receives information about a first transaction including a destination account identifier and a payment amount from a source computing device. The online system sends the source computing device a deep link to a second application. The online system receives a confirmation including a transaction identifier from the second application. The payment was sent to an intermediate payment processor, which records the first transaction in a ledger in association with a source account identifier. The online system receives an instruction to reverse the first transaction. The online system sends an instruction to generate a second transaction to a source account of the source computing device including the transaction identifier and not the source account identifier to the intermediate payment processor. The online system receives a confirmation of the second transaction, where the intermediate payment processor queried the ledger using the transaction identifier to identify the source account.

Disclosed herein are methods, systems, and devices for concealing account balances of permissionless distributed ledgers using multi-chain and/or directed acyclic graph (DAG) based structures, while maintaining publicly verifiable transactions. According to one embodiment, a computer-based method for recording a transaction in a ledger having a transacted amount, a first account balance associated with a sender and a second account balance associated with a receiver is disclosed. The computer-based method includes encrypting the transacted amount using a first shared key, decreasing the first account balance by the transacted amount, encrypting the first account balance with a first private key, increasing the second account balance by the transacted amount, encrypting the second account balance with a second private key.

At least one server enables a mobile device user to request delivery of cash or cash and goods at a user location. The at least one server operates to receive a transaction request message that includes data corresponding to a user financial account and an amount of value corresponding to the items to be delivered. Responsive to determining that the amount can be charged to the account, a message is sent to the mobile device. The user may use their mobile device to communicate with a delivery service to request delivery of the items. The at least one server operates to communicate with a terminal of the delivery service and the user mobile device to achieve delivery of the user requested items at a user location.

A ledger based dynamic digital address masking solution for reducing vulnerability of private cryptographic keys used during digital transactions. Tokenized digital transaction addresses may be stored in association with an actual distributed ledger reference address. The tokenized transaction address, or recipient token, may be used to complete a variety of transactions for digital asset exchange without exposing the transaction address's actual reference address on the distributed ledger.

The techniques herein are directed generally to a “zero-knowledge” data management network. Users are able to share verifiable proof of data and/or identity information, and businesses are able to request, consume, and act on the data—all without a data storage server or those businesses ever seeing or having access to the raw sensitive information (where server-stored data is viewable only by the intended recipients, which may even be selected after storage). In one embodiment, source data is encrypted with a source encryption key (e.g., source public key), with a rekeying key being an encrypting combination of a source decryption key (e.g., source private key) and a recipient's public key. Without being able to decrypt the data, the storage server can use the rekeying key to re-encrypt the source data with the recipient's public key, to then be decrypted only by the corresponding recipient using its private key, accordingly.

According to one embodiment of the invention, a subtoken corresponding to a primary token is generated. The primary token corresponds to a credential. The credential may be, for example, a primary account number (PAN) corresponding to a payment account. The subtoken may be a temporary, one-time use subtoken based on a primary token associated with the credential that allows a user to conduct a transaction from his or her account, while still providing security for the user's sensitive data. The subtoken may contain a header and an obfuscated portion. The header of the subtoken routes the subtoken to the entity issuing the subtoken for translation into the primary token. The obfuscated portion acts as a pointer to the primary token and data associated with the primary token. A same check digit may be included in the subtoken, the primary token, and the credential, in order to ensure that the transaction is not improperly denied.

Blockchain-based, smart contract platforms have great promise to remove trust and add transparency to distributed applications. However, this benefit often comes at the cost of greatly reduced privacy. Techniques for implementing a privacy-preserving smart contract is described. The system can keep accounts private while not losing functionality and with only a limited performance overhead. This is achieved by building a confidential and anonymous token on top of a cryptocurrency. Multiple complex applications can also be built using the smart contract system.

An in-application content transfer system that generates receiver identifiers to categorize a given exchange between two users. A first mobile device displays a plurality of user interface controls that are each selectable by a first user. In response to selection of a first control, an application message is generated that includes a unique identifier associated with a second user of a second device, and a user content that is associated with the first user and that is identified at least in part based on the selection of the first control. The application message, which is configured to seed an application on the second device with the unique identifier, is transmitted to the second device via peer-to-peer communication. The user content associated with the first user is then shifted to the second device.