Method for selective encryption within documents

• US 7,484,107 B2
• Filed: 04/15/2004
• Issued: 01/27/2009
• Est. Priority Date: 04/15/2004
• Status: Expired due to Fees

• Current Assignee: Kyndryl Incorporated (Kyndryl Holdings, Inc.)
• Original Assignee: International Business Machines Corporation
• Inventors: Forlenza, Randolph Michael, Berstis, Viktors
• Primary Examiner(s): Sheikh; Ayaz R
• Assistant Examiner(s): Henning; Matthew T
• Application Number:
  US10/824,806
• Publication Number:
  US 20050235163A1
• Time in Patent Office: 1,748 Days
• Field of Search: 713/193, 713/166
• US Class Current: 713/193
• CPC Class Codes: G06F 21/6209 to a single file or object, e.g. in a secure envelope, encrypted and accessed using a key, or with access control rules appended to the object itself
• CPC Class Codes: G06F 2221/2107 File encryption
• CPC Class Codes: G06F 2221/2113 Multi-level security, e.g. mandatory access control
• CPC Class Codes: G06F 2221/2149 Restricted operating environment
• CPC Class Codes: H04L 2209/60 Digital content management, e.g. content distribution
• CPC Class Codes: H04L 9/088 Usage controlling of secret information, e.g. techniques for restricting cryptographic keys to pre-authorized uses, different access levels, validity of crypto-period, different key- or password length, or different strong and weak cryptographic algorithms network architectures or network communication protocols for using time-dependent keys in a packet data network H04L63/068
• CPC Class Codes: H04L 9/14 using a plurality of keys or algorithms

Abstract

The present invention allows the user (author or creator) of a document to specify that certain portions of a document be selected for encryption while other portions of the document remain displayed as created. In addition, each encrypted section could have multiple encryption keys such that some viewers can review certain parts of the document while other viewers will not have that same access. The user could employ a standard word processing editor technique to highlight (or swipe) portions of a document that the user desires to be encrypted. The highlighted portion would then be ‘tagged’ with a surrounding attribute indicating to the word processor that this highlighted portion of the document is to be encrypted. The highlighted sections would also have encryption keys associated with the highlighted and encrypted section. Any one of the encryption keys for that section would decrypt that section. With proper authorization, any encrypted portion of a document would be displayed as part of the document. Without proper authorization, the display of the document would only contain the unencrypted portions of the document.

Claims

1. A method for selective encryption of multiple sections within a document comprising:

detecting a document encryption request;

activating a document encryption routine;

accessing a proposed document for encryption and tagging one or more sections of the proposed document as designated for encryption;

encrypting the tagged sections with multiple encryption keys;

extracting the plain text version of each encrypted sections from the document;

marking locations in the document where the extracted sections were located;

storing a copy of each encrypted section of the document for each key used in the encryption process, extracted sections from the document in an appendix attached to the document;

receiving a request to access an encrypted section of the document;

determining whether a received decryption key for the encrypted section of the document for which the access request was made is proper for that encrypted section, by selecting one of the encrypted copies of the document, selecting a key and attempting to decrypt the selected encrypted copies with the selected key by determining if a defined character string is in the selected copy of the encrypted section;

when the determination is that the received decryption key is proper, retrieving and decrypting the section of the document for which the access request was made; and

displaying the decrypted section of the document.

2. The method as described in claim 1 further comprising after said displaying step, the step of determining whether there is a request to access another encrypted section of the document.

3. The method as described in claim 2 further comprising when there is a determination that there is a request to access another encrypted section of the document, repeating the steps of:

determining whether a received decryption key for the encrypted section of the document for which the access request was made is proper for that encrypted section;

when the determination is that the received decryption key is proper, retrieving and decrypting the section of the document for which the access request was made; and

displaying the decrypted section of the document.