“…On-line handwritten signature verification has always been a very active area of research due to its high popularity for authentication scenarios [9] and the variety of open challenges that are still under research nowadays [14], e.g., one/few-shot learning [20,10,27,45], device interoperability [2,30,36,44], aging [22,41], types of impostors [40,21], signature complexity [24,43,47], template storage [8], etc. Despite all these challenges, the performance of on-line signature verification systems has been improved in the last years due to several factors, especially: i) the evolution in the acquisition technology going from devices specifically designed to acquire handwriting and signature in office-like scenarios through a pen stylus (e.g.…”