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US 7,681,050 B2Granted
Secure and replay protected memory storage
AssigneeTelefonaktiebolaget L M Ericsson (publ)
InventorsRolf Blom, Christian Gehrmann
Life of this patent
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Abstract
A device (e.g., mobile device) and method are described herein that can protect data stored in a rewritable openly accessible memory from replay attacks by using an integrity key and an encryption key to en/decrypt the data, integrity protect the data via a MAC calculation, and verify the data.
Claims17
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).
5 more elements
A method for protecting data stored in a rewritable openly accessible memory, said method comprising the steps of:
- verifying integrity of old data stored in the rewritable openly accessible memory by using one or more current keys (MIK_n and if desired MCK_n);
- calculating one or more new keys (MIK_n+1 and if desired MCK_n+1), wherein each new key (MIK_n+1 and if desired MCK_n+1) is calculated by using a pseudo random function (PRF), a secret key (PK) and a counter value plus one (n+1);
- protecting the verified old data and new data if any using the one or more new keys (MIK_n+1 and if desired MCK_n+1);
- storing the protected old data and the protected new data if any in the rewritable openly accessible memory;
- incrementing a monotone register to have a counter value (n+1);
- and
- erasing the verified old data from the rewritable openly accessible memory.
4 more elements
A device comprising:
- a tamper-proof module;
- a rewritable openly accessible memory;
- and
- said tamper-proof module includes a processor and protected software that performs the following actions:
- verify integrity of old data stored in the rewritable openly accessible memory by using one or more current keys (MIK_n and if desired MCK_n);
- calculate one or more new keys (MIK_n+1 and if desired MCK_n+1), wherein each new key (MIK_n+1 and if desired MCK_n+1) is calculated by using a pseudo random function (PRE), a secret key (PK) and a counter value plus one (n+1);
- protect the verified old data and new data if any using the one or more new keys (MIK_n+1 and if desired MCK_n+1);
- store the protected old data and the protected new data if any in the rewritable openly accessible memory;
- increment a monotone register to have a counter value (n+1);
- and
- erase the verified old data from the rewritable openly accessible memory.
8 more elements
A device comprising:
- a tamper-proof module;
- a rewritable openly accessible memory;
- and
- said tamper-proof module includes a processor and protected software that performs the following actions:
- generate key(s) using a pseudo random function (PRF), a secret key (PK) and a monotonic register counter value (n):
- protect an individual part of data using the generated key(s);
- and
- store the protected individual part of data and the monotonic register counter value (n) in said rewritable openly accessible memory, wherein said processor and said protected software functions to protect other individual parts of data using other generated key(s) and also stores the protected other individual parts of data along with corresponding other monotonic register counter values in said rewritable openly accessible memory.
5 more elements
A device comprising:
- a tamper-proof module;
- a rewritable openly accessible memory;
- and
- said tamper-proof module includes a processor and protected software that performs the following actions:
- generate key(s) using a pseudo random function (PRE), a secret key (PK) and a monotonic register counter value (n);
- protect an individual part of data using the generated key(s);
- and
- store the protected individual part of data and the monotonic register counter value (n) in said rewritable openly accessible memory, wherein said processor and said protected software functions to protect an integrity of each one of the individual parts of data by calculating a MAC and then protects an integrity of all of the individual parts by calculating a MAC over all of the stored monotonic register counter values associated with all of the individual parts of data.
5 more elements
Dependencies are inferred from the claim text.