Patent ID: 7681050

Claim:
A method for protecting data stored in a rewritable openly accessible memory, said method comprising the steps of: generating one or more keys (MIK_n and if desired MCK_n); protecting the data using said one or more keys (MIK_n and possibly MCK_n), wherein said protecting step includes confidentiality protecting the data by applying an encryption method to the data using the MCK_n storing the protected data in the rewritable openly accessible memory; and said generating step further includes: generating each key (MIK_n and if desired MCK_n) in a tamper-proof module by using a pseudo random function (PRE), a secret key (PK) and a monotonic register counter value (n); and generating each key (MIK_n and if desired MCK_n) in the tamper-proof module such that it is possible to generate the one or more keys (MIK_n and if desired MCK_n) and one or more new keys (MIK_n+1 and if desired MCK_n+1).