Secure memory having multiple security levels

US5991519A · kind A · utility

Assignee

• Atmel Corporation · US

Inventors

• Jean P. Benhammou · Colorado Springs, US
• Dennis F. Baran · Colorado Springs, US
• Phillip D. Tonge · Colorado Springs, US
• Edward L. Terry, Jr. · Widefield, US

Key dates

• Filing date: Oct 3, 1997
• Grant date: Nov 23, 1999
• Expiry date: Oct 3, 2017

Classification

• Technology area (CPC G): Physics
• CPC primary: G06Q20/35765
• WIPO field: IT methods for management
• WIPO sector: Electrical engineering

Abstract

According to the present invention, a secured memory comprises a first level security zone having an access code controlling access to the secured memory prior to an issuer fuse being blown, a security code attempts counter preventing access to the secured memory when a predetermined number of attempts at matching the access code have been made prior to resetting the security code attempts counter, a plurality of application zones, each of the plurality of application zones comprising: a storage memory zone, an application security zone having an application zone access code controlling access to the storage memory zone after an issuer fuse has been blown, an application zone security code attempts counter preventing access to the application zone when a predetermined number of attempts at matching the application zone access code have been made prior to resetting the application zone security code attempts counter, an erase key partition having an erase key code controlling erase access to the storage memory zone after an issuer fuse has been blown, and an erase key attempts counter preventing erase access to the application zone when a predetermined number of attempts at matching…