A computer-implemented method performed by a verification agent for verifying authorisation of an electronic transaction between an originator and a merchant, said method comprising the steps of: receiving at the verification agent a request from said merchant to process an electronic transaction for a predetermined amount of money, said request comprising data identifying a particular financial instrument of the originator; the verification agent dividing the predetermined amount into a plurality of charges; the verification agent converting each of said plurality of charges to a respective charge ratio by dividing each of said plurality of charges by the predetermined amount; the verification agent storing each of said charge ratios; the verification agent causing said financial instrument to be debited with each of said plurality of charges; receiving at the verification agent information relating to said plurality of charges from the originator, wherein said received information comprises a plurality of values relating to said plurality of charges debited to said financial instrument, wherein each of said values comprises one of the charges modified by a single currency exchange rate, the currency exchange rate being a factor of each value, said originator having obtained the information relating to said plurality of charges from an account relating to said financial instrument; the verification agent converting each of said received plurality of values to a respective value ratio by dividing each of said plurality of values by the sum of said plurality of values; the verification agent comparing each of said value ratios to said stored charge ratios; and the verification agent verifying authorisation of said transaction only if each of said value ratios matches a respective stored charge ratio within a predefined margin of error. receiving at the verification agent a request from said merchant to process an electronic transaction for a predetermined amount of money, said request comprising data identifying a particular financial instrument of the originator; the verification agent dividing the predetermined amount into a plurality of charges; the verification agent converting each of said plurality of charges to a respective charge ratio by dividing each of said plurality of charges by the predetermined amount; the verification agent storing each of said charge ratios; the verification agent causing said financial instrument to be debited with each of said plurality of charges; receiving at the verification agent information relating to said plurality of charges from the originator, wherein said received information comprises a plurality of values relating to said plurality of charges debited to said financial instrument, wherein each of said values comprises one of the charges modified by a single currency exchange rate, the currency exchange rate being a factor of each value, said originator having obtained the information relating to said plurality of charges from an account relating to said financial instrument; the verification agent converting each of said received plurality of values to a respective value ratio by dividing each of said plurality of values by the sum of said plurality of values; the verification agent comparing each of said value ratios to said stored charge ratios; and the verification agent verifying authorisation of said transaction only if each of said value ratios matches a respective stored charge ratio within a predefined margin of error.