Abstract: The present disclosure inter alia presents a method of generating a temporary authentication value, for use in a secure transmission to a service provider system having one or several computer servers. The method starts with receiving a first identification data and receiving a security data associated with the first identification data. Thereafter, a hash function is applied to the first identification data and the security data to generate a temporary authentication value. The generated temporary authentication value is divided into a first and a second part. The method thereafter comprises transmitting only the second part of the divided temporary authentication value to the service provider system for verification.

Abstract: The present disclosure presents a method for a card based transaction between a mobile terminal and a service provider system having one or several computer servers. The mobile terminal obtains a CSC from credit card/debit card. The mobile terminal obtains a data seed. The mobile terminal applies a minimal perfect hash function to the CSC as well as the data seed to generate a temporary CSC. The mobile terminal initiates a card based transaction with the service provider system utilizing the generated temporary CSC. The service provider system obtains the temporary CSC and applies a same minimal perfect hash function to the temporary CSC until a match is found between the obtained temporary CSC and one CSC stored at the service provider system. In response to a match the service provider system continues the initiated card based transaction with the mobile terminal.