Encrypt and decrypt the file
To encrypt the existing file or change its encryption mode use SetFileEncryption() method of SolFSStorage class. If the file was not encrypted, pass empty string in OldPassword parameter of this method. To change the file password (and possibly encryption mode), specify the current password in OldPassword parameter.
Note: encrypting, decrypting or re-encrypting the file takes certain time which can be significant on large files.