Migrate unknown Oracle database user's encrypted password - 11g hash to 12c database I have tried to search extensively but could not find.Oracle has changed the encryption (spare4) in 12c.

I am trying to see if its possible to migrate / copy the encrypted password hash of a user in 11g database to 12c.

I have done this before on 11g to 11g, but not able to replicate / find how to do this on 11g to 12c.

Thanks!
This isn't really a database administration question. To "migrate" a hashed password to a different hash algorithm you will need to "unhash" it first, that is, find the original password from its salted SHA1 hash, which is not practical.

You'll need to reset that user's password.