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:
Oct. 03, 1995
Filed:
Feb. 27, 1992
Yasuhiro Okuno, Kawasaki, JP;
Tadashi Yamakawa, Yokohama, JP;
Masaaki Nagashima, Kawasaki, JP;
Takayuki Sasaki, Yokohama, JP;
Takahiro Kurosawa, Yokohama, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
In storing data in one file, consisting of a plurality of blocks of data, a first code is generated by converting a password and a predetermined portion of each of the blocks of data. This portion may be, for example, the data block itself or identification information such as a name. The code is stored in correspondence to the stored data. In reading the stored data, a second code is generated by performing the same conversion on the password and the predetermined portion of the stored data. A comparison is made between the generated second code and the first code stored. Failure of the two to match indicates that an improper rewrite has occurred. In such a case, that occurrence may simply be noted, access to the data may be prohibited; more generally, what processing is performed, or is permitted, is varied according to the result of the comparison.