Abstract: A method, computer program product, and computer system are provided for verifying transactions. The method includes analyzing past transactions and categorizing the transactions into multiple categories; analyzing a social network of a transaction owner to identify a set of closest social network contacts for the transaction owner for each transaction category; and proposing the set of closest social network contacts as candidate transaction verifier contacts to be used by a transaction verifying entity for incoming transactions of the transaction category by the transaction owner to the transaction verifying entity.

Abstract: Disclosed are techniques for function-defined output streams corresponding to combinations of events published to one or more event notification streams in an event-driven architecture with a plurality of event notification streams. An output function is received defining a combination of event notifications with criteria for selecting which event notifications to combine from one or more event notification streams. The one or more event notification streams are parsed, and event notifications are selected to initialize a new event notification stream, where event notifications in this stream correspond to instances of the output function when provided a set of event notifications from the one or more event notification streams as input values. When an event notification is published to the one or more event notification streams meeting the criteria specified in the output function, the new event notification stream publishes an event notification corresponding to an output value from the output function.

Abstract: A computer-implemented method, a computer program product, and a computer system for using a user location as a security factor for online services. Upon receiving from a computing device of a user a request for a digital service allowed in a geofence, a first computer hosting a digital service provider generates an original one-time password (OTP) and sends the original OTP to a second computer hosting a communication service provider. The second computer encrypts the original OTP using a private key for a mobile network cell communicating with a mobile device of the user and sends an encrypted OTP to the mobile device. Upon receiving the encrypted OTP from the computing device, the first computer decrypts the encrypted OTP, using public keys for one or more cells covering the geofence. Upon determining a decrypted OTP matches the original OTP, the first computer allows the digital service to be provided.

Abstract: Disclosed are techniques for function-defined output streams corresponding to combinations of events published to one or more event notification streams in an event-driven architecture with a plurality of event notification streams. An output function is received defining a combination of event notifications with criteria for selecting which event notifications to combine from one or more event notification streams. The one or more event notification streams are parsed, and event notifications are selected to initialize a new event notification stream, where event notifications in this stream correspond to instances of the output function when provided a set of event notifications from the one or more event notification streams as input values. When an event notification is published to the one or more event notification streams meeting the criteria specified in the output function, the new event notification stream publishes an event notification corresponding to an output value from the output function.