System for performing secure large monetary transactions through mobile communication devices

A computer-implemented method for securing large monetary transactions over mobile phones and smartphones known as “OTP-swap”, the method comprising:

• a. interpreting provided transaction characteristics such as proposed counterparty and proposed transaction amount;
• b. recognizing a situation where a trade is possible through matching of client-originating information and previously collected service-provider information;
• c. triggering an OTP-swap mechanism if the transaction is plausible;
• d. sending of two independent, random OTP codes, one to each of the parties to the transaction, together with the proposed transaction details;
• e. parties to the transaction orally exchanging the received OTPs to signify mutual agreement to the transaction, and sending each other's OTP back to the service provider;
• and
• f. recognizing of the OTPs sent back by parties to the transaction within a limited acceptance timeframe and maximum permissible errors.