A method of multi-step activation of fingerprint authentication for a user of a smart card, the smart card comprising a fingerprint sensing system including a fingerprint sensor configured for capturing a fingerprint representation of a fingerprint pattern of a finger of a user, a wireless transceiver for wireless communication with an electronic transaction terminal and processing circuitry connected to and configured to control the operation of the fingerprint sensor, the method comprising the steps of: - acquiring, using the fingerprint sensor, a partial fingerprint representation of a portion of the user's fingerprint during a present step in the multi-step fingerprint authentication activation, wherein the present step in the multi-step fingerprint authentication activation corresponds to one transaction of a plurality of consecutive transactions, and the user is authenticated at the electronic transaction terminal by requesting the user to input a PIN code in the electronic transaction terminal for each of the plurality of consecutive transactions; - extracting, using the processing circuitry, fingerprint features from the partial fingerprint representation, forming a present set of fingerprint features; - determining, using the processing circuitry, a similarity level between the present set of extracted fingerprint features and sets of previously extracted fingerprint features, wherein the sets of previously extracted fingerprint features are formed during a preceding step in the multi-step fingerprint authentication activation, wherein the preceding step in the multi-step fingerprint authentication activation corresponds to another transaction of the plurality of consecutive transactions; - forming, using the processing circuitry, a combined set of extracted fingerprint features if the similarity level is above a first threshold; - completing, if an enrollment criterion is met, the multi-step fingerprint authentication activation by forming a fingerprint template based on the combined set of extracted fingerprint features; - requesting the user to input the PIN code in the electronic transaction terminal; - authenticating the PIN code; and - saving the fingerprint template together with an identifier for the fingerprint to thereby enroll the fingerprint of the user's finger only if the PIN code has been successfully authenticated. - acquiring, using the fingerprint sensor, a partial fingerprint representation of a portion of the user's fingerprint during a present step in the multi-step fingerprint authentication activation, wherein the present step in the multi-step fingerprint authentication activation corresponds to one transaction of a plurality of consecutive transactions, and the user is authenticated at the electronic transaction terminal by requesting the user to input a PIN code in the electronic transaction terminal for each of the plurality of consecutive transactions; - extracting, using the processing circuitry, fingerprint features from the partial fingerprint representation, forming a present set of fingerprint features; - determining, using the processing circuitry, a similarity level between the present set of extracted fingerprint features and sets of previously extracted fingerprint features, wherein the sets of previously extracted fingerprint features are formed during a preceding step in the multi-step fingerprint authentication activation, wherein the preceding step in the multi-step fingerprint authentication activation corresponds to another transaction of the plurality of consecutive transactions; - forming, using the processing circuitry, a combined set of extracted fingerprint features if the similarity level is above a first threshold; - completing, if an enrollment criterion is met, the multi-step fingerprint authentication activation by forming a fingerprint template based on the combined set of extracted fingerprint features; - requesting the user to input the PIN code in the electronic transaction terminal; - authenticating the PIN code; and - saving the fingerprint template together with an identifier for the fingerprint to thereby enroll the fingerprint of the user's finger only if the PIN code has been successfully authenticated.