I believe you have to create a new one or find the original uncorrupted digital signature certificate.
What kind of certificate? Was this a self-signed certificate that you created using Acrobat? If so, then the easiest waay for you is to create another one.
Have you recieved this certificate from some Certificate Authority? If this is the case you should still have the original .pfx or .p12 file on your hard drive and you can use Acrobat UI to attach this Digital ID to the new version of Acrobat.
I am not sure what do you mean by "certificate have been corrupted'? Do you still have the certificate file? Can yo uopen it in WIndows (by double-clicking the file)? Itis very unusual that a file is corrupted on disk. If this happens then there is no other remedy than to replace the file with a good one.
It is also possible that you misspelled the original password or do not remember it correctly. There is no remedy if this is the case.