METHOD FOR ENCRYPTING OR DECRYPTING A N-TUPLE OF DATA WITH A N-TUPLE OF PREDETERMINED SECRET KEYS

A method for encrypting or decrypting a n-tuple of data ({ai}i∈[[0,n-1]]) with a n-tuple of secret keys ({ki}i∈[[0,n-1]]). The method uses a data-processor to perform the steps of: (a) for each element (ai), determining m>n first internal states ({yij}j∈[[0,m-1]]) by application of m first operations, each: represented by a table (Tij), and defined as the combination of a single bijective internal encoding (Gij), of a non-linear sharing function (Di, Ei, Fi . . . ), and of a given non-linear permutation function (ƒ) parameterized with the secret key (ki), and (b) for each n-tuple of first internal states ({yij}i∈[[0,n-1]]), determining a second internal state (zj) by application of a second operation: represented by a table (TLj), and defined as the combination of a second single bijective internal encoding (GLj), a linear multiplexing function (L), and the inverses of the first bijective internal encodings (Gij).