A computer implemented system for providing challenge-response solutions to authenticate a user, said system comprising a web server: the web server includes: • interlinking means adapted to interlink a plurality of images with unique index values such that each of said images has a corresponding unique index value; and • registration means adapted to enable said user to select at least two interlinked images for the purpose of registration, said registration means further including: • generation means adapted to generate at least two image matrices having interlinked images, wherein each of said image matrices include at least one interlinked image selected by said user, said generation means further adapted to arrange the unique index values corresponding to said interlinked images in the form of matrices and generate index-value matrices, said generation means still further adapted to transmit said image matrices and index-value matrices; and • communication means adapted to enable said user to specify the sequence in which said image matrices and said index-value matrices are to be traversed, said sequence selected from the group of sequences consisting of clockwise sequence, anticlockwise sequence, clockwise Z sequence, anti clockwise Z sequence; characterised in that the web server includes: • challenge generation means adapted to generate and transmit an authentication challenge of the form of a one-time equation, said challenge generation means further including: • computing means adapted to compute the value of said one-time equation based on the sequence specified by said user, the interlinked images selected by the user during registration and the corresponding unique index-values; and • storage means adapted to store the value of said one-time equation; said challenge generation means further adapted to prompt said user to calculate value of said one-time equation by using said image matrices, said index-value matrices and said sequence; • comparator means adapted to compare the value stored in said storage means with the value calculated by said user; and • authentication means adapted to authenticate said user in the event that said value calculated by said user is equivalent to the value stored in said storage means. • interlinking means adapted to interlink a plurality of images with unique index values such that each of said images has a corresponding unique index value; and • registration means adapted to enable said user to select at least two interlinked images for the purpose of registration, said registration means further including: • generation means adapted to generate at least two image matrices having interlinked images, wherein each of said image matrices include at least one interlinked image selected by said user, said generation means further adapted to arrange the unique index values corresponding to said interlinked images in the form of matrices and generate index-value matrices, said generation means still further adapted to transmit said image matrices and index-value matrices; and • communication means adapted to enable said user to specify the sequence in which said image matrices and said index-value matrices are to be traversed, said sequence selected from the group of sequences consisting of clockwise sequence, anticlockwise sequence, clockwise Z sequence, anti clockwise Z sequence; • generation means adapted to generate at least two image matrices having interlinked images, wherein each of said image matrices include at least one interlinked image selected by said user, said generation means further adapted to arrange the unique index values corresponding to said interlinked images in the form of matrices and generate index-value matrices, said generation means still further adapted to transmit said image matrices and index-value matrices; and • communication means adapted to enable said user to specify the sequence in which said image matrices and said index-value matrices are to be traversed, said sequence selected from the group of sequences consisting of clockwise sequence, anticlockwise sequence, clockwise Z sequence, anti clockwise Z sequence; • challenge generation means adapted to generate and transmit an authentication challenge of the form of a one-time equation, said challenge generation means further including: • computing means adapted to compute the value of said one-time equation based on the sequence specified by said user, the interlinked images selected by the user during registration and the corresponding unique index-values; and • storage means adapted to store the value of said one-time equation; said challenge generation means further adapted to prompt said user to calculate value of said one-time equation by using said image matrices, said index-value matrices and said sequence; • computing means adapted to compute the value of said one-time equation based on the sequence specified by said user, the interlinked images selected by the user during registration and the corresponding unique index-values; and • storage means adapted to store the value of said one-time equation; • comparator means adapted to compare the value stored in said storage means with the value calculated by said user; and • authentication means adapted to authenticate said user in the event that said value calculated by said user is equivalent to the value stored in said storage means.