The application concerns a method of authenticating an object, the object comprising an identification substance including at least one amorphous phase, at least one crystalline phase and at least one complex metallic phase. The method includes the steps of: subjecting the identification substance of a candidate object to XRD analysis to determine an XRD signature thereof; comparing the XRD signature of the candidate object to a reference XRD signature, and concluding to the authenticity of the object when its XRD signature substantially matches the reference XRD signature.