I am trying to figure out the scope of SHA1 deprecation for existent signatures. Reading this.An attacker (after 110 years) could present a fake document for a valid signature
I believe this only affect to integrity between signature and document and not to signatory identity (except if a SHA1 certificate is used?)
I think adding a timestamp on the signature, even with SHA512, does not avoid the problem. It is needed to re-hash the document and apply a timestamp on signature+new hash
Is that so?