The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 18, 2007
Filed:
Jan. 27, 2003
Per Erwin Jonas, Westbrook, ME (US);
Allen Leonid Roginsky, Durham, NC (US);
Nevenko Zunic, Hopewell Junction, NY (US);
Per Erwin Jonas, Westbrook, ME (US);
Allen Leonid Roginsky, Durham, NC (US);
Nevenko Zunic, Hopewell Junction, NY (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A method for protecting data for access by a plurality of users. A server encrypts data using a master key and a symmetric encryption algorithm. For each authorized user, a key encryption key (KEK) is derived from a passphrase, and the master key is encrypted using the KEK. The server posts the encrypted data and an ancillary file that includes, for each user, a user identifier and the master key encrypted according to the user's KEK. To access the data, a user enters the passphrase into a client, which re-derives the user's KEK, and finds, in the ancillary file, the master key encrypted using the user's KEK. The client decrypts the master key and then decrypts the data. A KEK may be derived from a natural language passphrase by hashing the passphrase, concatenating the result and a predetermined text, hashing the concatenation, and truncating.