1. A method to process a file, comprising: in response to a file creator creating the file, obtaining a seed value; encrypting the seed value using a private cryptographic key associated with the file creator to form an encrypted seed value; storing as part of the file a public cryptographic key associated with the file creator, the seed value and the encrypted seed value; computing a file integrity value using the encrypted seed value and file data; and storing as part of the file the computed file integrity value.