Abstract: A method for determining indoor position of a mobile device, the method may include (i) receiving, by the mobile device, acoustic beacon signals transmitted from indoor transmitters of known location; wherein adjacent indoor transmitters transmit acoustic beacon signals of different frequencies, the different frequencies are selected out of a group of frequencies within an acoustic frequency range that starts above 15 Kilohertz, and (ii) determining a location of the mobile device within an indoor space, based on a mapping between (a) locations within the indoor space, and (b) acoustic signatures associated with the locations, wherein each acoustic signature comprises a frequency and an intensity parameter of acoustic beacon signals received at a location associated with the acoustic signature.

Abstract: A method for measuring a distance between a first device and a second device, the method may include playing, by a first sound output unit, a first correlation tone; receiving, by a first sound sensing unit, the first correlation tone; detecting a start point of a reception of the first correlation tone; receiving, by the first sound sensing unit, a second correlation tone; wherein the second correlation tone is played by a second sound output unit in response to a reception, by a second sound sensing unit, of the first correlation tone; detecting a start point of a reception of the second correlation tone; receiving, by the first sound sensing unit, information about a processing time of the second device; calculating, by a first processing unit, a timing difference between (i) the start point of the reception of the second correlation tone, and (ii) the start point of the reception of the first correlation tone; and determining the distance between the first device and the second device based on a differenc

Abstract: A method of performing a secure transaction using non-secure communications, including: contacting a service provider by a customer to perform a transaction; sending an non-secure message by the service provider over a communication network using a communication device with details of the transaction to a transaction server; initiating a secure transaction at the transaction server; generating two one-time passwords at the transaction server; sending the first one-time password to a communication device of the customer and sending the second one-time password to the service providers communication device; revealing the first one-time password to the service provider by the customer; replying to the transaction server by the service provider with a message based on both one-time passwords; completing the transaction at the transaction server.

Abstract: A method of performing a secure transaction using non-secure communications, including: contacting a service provider by a customer to perform a transaction; sending an non-secure message by the service provider over a communication network using a communication device with details of the transaction to a transaction server; initiating a secure transaction at the transaction server; generating two one-time passwords at the transaction server; sending the first one-time password to a communication device of the customer and sending the second one-time password to the service providers communication device; revealing the first one-time password to the service provider by the customer; replying to the transaction server by the service provider with a message based on both one-time passwords; completing the transaction at the transaction server,