A device for determining an estimate of at least one secret key used during a number of executions of a cryptographic function used by at least one cryptographic algorithm, said number of executions of said cryptographic function being at least equal to two, wherein the device comprises: - an analysis unit configured to determine a plurality of sets of vectorial leakage traces from a side-channel information acquired during said number of executions of said cryptographic function, the number of said sets of leakage traces being at least equal to two, each set of leakage traces corresponding to one execution of said cryptographic function and comprising at least one leakage trace, said plurality of sets of leakage traces being represented by a measurements matrix, said measurements matrix comprising column vectors, a column vector comprising leaking traces acquired during one execution of said cryptographic function; - a processing unit configured to determine a statistical distribution of said plurality of sets of leakage traces, said statistical distribution being dependent on a leakage function, said leakage function being represented by a set of unknown real values corresponding to its coordinates in a canonical basis of functions spanning a space vector, said leakage function being the same for all said sets of leakage traces, said processing unit being further configured to determine said statistical distribution of said plurality of sets of leakage traces depending on a noise of a known covariance matrix, wherein the device is configured to determine said at least one secret key from said statistical distribution of the plurality of sets of leakage traces represented by said measurements matrix using an estimation algorithm according to the maximization of a performance metric, wherein said estimation algorithm is an iterative algorithm which is applied to jointly determine estimates of said unknown real values representing said leakage function and said at least one secret key. - an analysis unit configured to determine a plurality of sets of vectorial leakage traces from a side-channel information acquired during said number of executions of said cryptographic function, the number of said sets of leakage traces being at least equal to two, each set of leakage traces corresponding to one execution of said cryptographic function and comprising at least one leakage trace, said plurality of sets of leakage traces being represented by a measurements matrix, said measurements matrix comprising column vectors, a column vector comprising leaking traces acquired during one execution of said cryptographic function; - a processing unit configured to determine a statistical distribution of said plurality of sets of leakage traces, said statistical distribution being dependent on a leakage function, said leakage function being represented by a set of unknown real values corresponding to its coordinates in a canonical basis of functions spanning a space vector, said leakage function being the same for all said sets of leakage traces, said processing unit being further configured to determine said statistical distribution of said plurality of sets of leakage traces depending on a noise of a known covariance matrix, <EOS>