Electronic document protection method and electronic document protection system

摘要

A secure content (100) object protects electronic documents from unauthorized use. The secure content object includes an encrypted electronic document (12), a multi-key encryption table (13) having at least one multi-key component, an encrypted header (11) and a user interface device (10). The encrypted document (12) is encrypted using a document encryption key associated with a multi-key encryption method. The encrypted header (11) includes an encryption marker formed by a random number followed by a derivable variation of the same random number. The user interface device (10) enables a user to input a user authorization. The user authorization is combined with each of the multi-key components in the multi-key encryption key table and used to try to decrypt the encrypted header. If the encryption marker is successfully decrypted, the electronic document may be decrypted. Multiple electronic documents or a document and annotations may be protected by the secure content object. IMAGE