Method for authenticating an illustration

The invention relates to a method for authenticating an illustration, comprising-encoding a message in the form of a two-dimensional barcode comprising blocks, each block coding a fragment of said message and comprising a set of coding sub-blocks, each sub-block comprising a set of binary elements. It is essentially characterised in that the encoding comprises prior steps consisting in:-defining or identifying a set of noteworthy points in the illustration,-calculating a set of attributes depending on certain at least of the noteworthy points,-selecting, among the calculated attributes, at least one attribute allowing a digital fingerprint to be defined-optionally compressing said digital fingerprint,-optionally signing said digital fingerprint by means of a cryptographic signature, and-recording in the message one among:-a set of at least one attribute,-the digital fingerprint,-the compressed digital fingerprint, and-the signed and optionally compressed digital fingerprint.