PKI based digital signature ensures that a given document was created by a known party and that the document was not altered in transit.
The complexity of algorithms used to create digital signatures grows over time, making it impossible to break or forge. Digital timestamps ensures the time for digital data.
With the right technology digital signatures are practically fraud proof.
Results from a Digital Identification project
After 15 years since the first issued digital Identity in Estonia, with the help of Nortal, there has not been a single forged digital signature.