Abstract: A method of encoding and/or decoding data is described, having the steps of: generating a challenge code, the challenge code being based on a pattern associated with at least one challenge arrangement having duplicated signs, encrypting the challenge code using a one-way hashing function to obtain a temporary encryption key, generating encoded data by encoding the data using a two-way transcoding function using the obtained temporary encryption key, wherein data is decoded using the two-way transcoding function and a subsequently obtained user temporary encryption key when the subsequently obtained user temporary encryption key matches the previously obtained temporary encryption key used to encode the data.

Abstract: In one aspect, it is described a method of encoding data, having the steps of: generating a challenge code, the challenge code being based on a pattern associated with at least one challenge arrangement having duplicated signs; encrypting the challenge code using a one-way hashing function to obtain a temporary encryption key; and generating encoded data by encoding the data using a two-way transcoding function using the obtained temporary encryption key.

Abstract: The invention relates to a method of authentication of a user (U), comprising the steps of: obtaining an authentication code of a user, the authentication code comprising at least six elements based on a memorable identification pattern, MIP, associated with at least one authentication arrangement, dividing the authentication code into at least two authentication segments each forming a subset of the elements of the authentication code (MIP); encoding each of the authentication segments using a one-way hashing function; storing the encoded authentication segments for use in a validation in a database (11); obtaining a challenge code (OTC) from the user, the challenge code being based on a pattern associated with at least one challenge arrangement comprising duplicated signs, and validating the challenge code (OTC) only if each portion of the challenge code (OTC) corresponding to an authentication segments is validated. The invention also relates to a system for performing such a method.