DE102014201038A1 - Method for encrypting, storage system for a vehicle, motor vehicle with a storage system and computer-readable storage medium - Google Patents

Abstract

Methods are disclosed for encrypting first data (20) in a first memory (75) and writing the encrypted first data (25) to a nonvolatile second memory (80), comprising the steps of: encrypting the first data (20) in the first memory first memory (75) by means of a stream encryption algorithm or by means of a block encryption algorithm, wherein the block encryption algorithm is operated to generate a stream encryption in counter-mode; Comparing the encrypted first data (25) in the first memory (75) with encrypted second data (35) in the nonvolatile second memory (80) and determining the portion of the encrypted first data (25) that is not identical to the encrypted second data is (35); and writing only the determined portion (27) of the encrypted first data (25) from the first memory (75) to the non-volatile second memory (80) which is not identical to the encrypted second data (35).

Description

The invention relates to a method for encrypting according to claim 1 and according to claim 2, a storage system for a vehicle according to claim 8 and according to claim 9, a motor vehicle having such a storage system according to claim 15 and a computer-readable storage medium according to claim 16.

Sensitive data is often encrypted for reasons of data security (access) and data protection or the protection of trade secrets and / or privacy. Many standards or laws also require that data must be stored in encrypted form. Many encrypted stored data often needs to be updated, i. the encrypted data is read, decrypted, changed and then stored encrypted again.

Write accesses or writes to many nonvolatile memories (in particular, unlike read accesses) result in significant aging of the memory and a reduction in the (remaining) lifetime of the memory, i. Many non-volatile memories have a limited number of write accesses before the memory is no longer (fully) functional. In particular, in storage systems in a motor vehicle, the failure of a small part of the electronics, here the memory, leads to large repair costs.

The object of the invention is to disclose a method or a memory system by means of which first data are stored encrypted in a non-volatile memory in which encrypted second data are already present, with the least possible reduction in the remaining lifetime of the non-volatile memory.

This object is achieved by a method according to claim 1 and a method according to claim 2.

In particular, the object is achieved by a method for encrypting first data in a first memory and writing the encrypted first data into a non-volatile second memory, comprising the steps:
Encrypting the first data in the first memory by means of a stream encryption algorithm or by means of a block encryption algorithm, wherein the block encryption algorithm is preferably operated to generate counter-mode stream encryption; Comparing the encrypted first data in the first memory with encrypted second data in the non-volatile second memory and determining the portion of the encrypted first data that is not identical to the encrypted second data; and writing only the particular portion of the encrypted first data from the first memory to the non-volatile second memory that is not identical to the encrypted second data.

An essential point of the invention is that prior to storing the encrypted data, a comparison is made with encrypted data already stored in the non-volatile memory and only the data which is not already identical in the non-volatile memory is written to the non-volatile memory. volatile memory are present. An advantage of this is that the number of write accesses is reduced. This prolongs the lifetime of the non-volatile memory. In addition, the time to save decreases because fewer write accesses are required to store the data.

In particular, the object is also achieved by a method for encrypting first data in a first memory and writing the encrypted first data into a non-volatile second memory, comprising the steps:
Decrypting encrypted second data stored in the non-volatile second memory; Comparing the decrypted second data with the non-encrypted first data stored in the first memory and determining the portion of the unencrypted first data that is not identical to the decrypted second data;
Encrypting at least the particular portion of the non-encrypted first data that is not identical to the decrypted second data by means of a stream encryption algorithm or a block encryption algorithm, wherein the block encryption algorithm is operated to generate counter-mode stream encryption;
and writing exclusively to the nonvolatile second memory the specific portion of the encrypted first data corresponding to the portion of the non-encrypted first data that is not identical to the decrypted second data.

An essential point of the invention is that the second data, which is encrypted in the nonvolatile memory, is decrypted, compared with the (unencrypted) first data, at least the part of the first data which is not already identical as second data is encrypted (in encrypted form) is present in the nonvolatile memory, and this part of the first data is written encrypted from the first memory into the nonvolatile second memory. An advantage of this is that the number of Write access is reduced. This prolongs the lifetime of the non-volatile memory. In addition, the time to save decreases because fewer write accesses are required to store the data.

As the first memory, a volatile memory such as DRAM, RAM and / or SRAM may be used. An advantage of this is that the time for encryption or decryption is reduced because a volatile memory allows very short access times. In addition, it ensures that any unencrypted data is deleted when the power to the first memory is disconnected.

As a first step, encrypted second data stored in the nonvolatile second memory may be read and the encrypted second data may be decrypted and subsequently the decrypted second data may be altered to obtain the unencrypted first data in the first memory. An advantage of this is that the first data is obtained from the existing encrypted second data. Thus, temporarily stored second data can be read, decrypted and then changed to obtain the first data. This or the changed parts of the first data are then stored in encrypted form. Thus, the second data stored in the non-volatile memory has merely been updated.

In another embodiment, a symmetric block encryption algorithm is used as the block encryption algorithm. This reduces the time required for encryption or decryption.

As a stream encryption algorithm, a symmetric stream encryption algorithm can be used. The advantage of this is that the time required for encryption or decryption is reduced.

As the second nonvolatile memory, a flash EEPROM memory can be used. As a result, a particularly cost-effective system for carrying out the method can be used. In addition, the access time to a flash EEPROM is very short, so that the execution time for the method is reduced.

The object is achieved according to the device by a storage system for a vehicle, comprising: a first memory for storing unencrypted first data, a nonvolatile second memory for storing encrypted second data, a computing device for encrypting the first data by means of a stream encryption algorithm or by means of a A block encryption algorithm, wherein the block encryption algorithm is operated to generate a counter-mode stream encryption, comparison means for comparing the encrypted first data with the encrypted second data, and determining the portion of the encrypted first data which is not identical to the encrypted second data, and a writing device for writing only the specific part of the encrypted first data that is not identical to the encrypted second data to the non-volatile second one Storage.

An essential point of the invention is that the storage system is designed so that prior to storing the encrypted data, a comparison with encrypted data already stored in the non-volatile memory and only the data is written in the non-volatile memory, the are not already identical in the non-volatile memory. An advantage of this is that the number of write accesses is reduced. This extends the lifetime of the non-volatile memory and thus of the memory system as a whole. In addition, the time to save decreases because fewer write accesses are required to store the data.

Alternatively, the object is also achieved by a storage system for a vehicle, comprising a first memory for storing unencrypted first data, a nonvolatile second memory for storing encrypted second data, a computing device for encrypting the unencrypted first data, and Decrypting the encrypted second data stored in the non-volatile second memory by means of a stream encryption algorithm or a block encryption algorithm, wherein the block encryption algorithm is operated to generate counter-mode stream encryption, comparing means for comparing the non-encrypted first data the decrypted second data and determining the portion of the non-encrypted first data that is not identical to the decrypted second data and the portion of the encrypted first data, d it corresponds to the part of the non-encrypted first data which is not identical with the decrypted second data, and a writing means for writing only the certain part of the encrypted first data corresponding to the part of the non-encrypted first data which is not identical to the decrypted second data is in the non-volatile second memory.

An essential point of the invention is that the system is designed so that the second data, which is encrypted in the nonvolatile memory, is decrypted, compared with the first data, at least the part of the first data which is not encrypted second data is already identical (in encrypted form) in the nonvolatile memory, and this part of the first data is written encrypted from the first memory into the nonvolatile second memory. An advantage of this is that the number of write accesses is reduced. This prolongs the lifetime of the non-volatile memory. In addition, the time to save decreases because fewer write accesses are required to store the data.

The first memory may be a volatile memory such as DRAM, RAM and / or SRAM. An advantage of this is that the time for encryption or decryption is reduced because a volatile memory allows very short access times. In addition, it ensures that any unencrypted data is deleted when the power to the first memory is disconnected.

The computing means may be adapted to read and decrypt the encrypted second data stored in the nonvolatile second memory to store the decrypted second data in the first memory and to change the stored decrypted second data in the first memory to be decrypted second data to gain the non-encrypted first data in the first memory. An advantage of this is that the first data is obtained from the existing encrypted second data. Thus, temporarily stored second data can be read, decrypted and then changed to obtain the first data. This or the changed parts of the first data are then stored in encrypted form. Thus, the second data stored in the non-volatile memory has merely been updated.

The block encryption algorithm may be a symmetric block encryption algorithm. This reduces the time required for encryption or decryption.

The stream encryption algorithm may be a symmetric stream encryption algorithm. The advantage of this is that the time required for encryption or decryption is reduced.

In another embodiment, the second non-volatile memory is a flash EEPROM memory. This reduces the provisioning costs of the storage system. In addition, the access time to a flash EEPROM is very short, so that the execution time for the method is reduced.

Also disclosed and claimed is a motor vehicle having a storage system with one or more of the feature combinations described above.

In addition, a computer readable storage medium is claimed that stores executable machine instructions that cause a computer to implement a method with one or more of the above feature combinations as they are executed.

Preferred embodiments will be apparent from the dependent claims. The invention will be explained in more detail with reference to drawings of exemplary embodiments. Show here

1 the schematic structure of a first embodiment of the storage system according to the invention;

2 a representation of the schematic sequence when comparing the encrypted data;

3 a representation of the schematic sequence when comparing the decrypted data; and

4 a schematic representation of the counter-mode of a block encryption algorithm according to the prior art.

In the following description, the same reference numerals are used for the same and the same parts acting.

1 shows the schematic structure of a first embodiment of the storage system according to the invention 70 , The storage system 70 includes a first memory 75 and a second memory 80 , The first store 75 is for example a DRAM, RAM and / or SRAM of a computer. The second memory 80 is a non-volatile memory. The second memory 80 For example, it may be a flash memory, a flash EEPROM memory, a memory card (eg, an SD card), a hard disk, a CD, a DVD, a floppy disk, an EPROM, or the like.

The storage system 70 further comprises a writing device 95 , the data from the first memory 75 in the second memory 80 can write. The writing device 95 can also get data from the second memory 80 in the first store 75 read. In addition, the storage system includes 70 a comparison device 90 that with the first memory 75 and the second memory 80 is connected and data from the first memory 75 with data from the second memory 80 as well as multiple data in the first memory 75 compare with each other and can determine the data that is different. In addition, a computing device 85 as part of the storage system 70 present, the computing device 85 both on the first memory 75 as well as the second memory 80 can access.

The storage system 70 or the individual devices of the storage system can be controlled by a control device (not shown). In particular, the storage system 70 installed in a motor vehicle or can be installed in such. For example, the storage system 70 Part of a control device of a motor vehicle or is connected to this control device.

First dates 20 are unencrypted in the first store 75 stored or held. The first dates 20 For example, status data or other data about various components of a motor vehicle may be. In addition, also error messages of the motor vehicle in the first data 20 be included. It is also conceivable that individual settings of seats and / or mirrors in the first data 20 are included. The first dates 20 For example, obtained from the second data may control corresponding motors or actuators of the seats and / or the mirrors so that they are moved accordingly to the positions indicated in the data. Also, the (fine) tuning of the engine or the transmission may be included in the first and / or second data, so that depending on the driver, the corresponding data are used to control the engine or the transmission. For example, the mileage of the motor vehicle in the first data 20 be saved.

The first dates 20 become, for example, second data 35 which is encrypted in the second memory 80 are saved by the second data 35 by means of the computing device 85 be decrypted, and then, for example, due to status changes or an increase in mileage, the data changed or changed. These changed or changed data provide the first data 20 represents.

It is also conceivable that the first dates 20 new (ie not from the second data 25 ) to be generated.

2 shows the schematic sequence of the comparison of the encrypted first data 25 with the encrypted second data 35 , The unencrypted first dates 20 are first by means of the computing device 85 Encrypted, so that encrypted first data 25 available. This encrypted first data 25 be in the first store 75 saved. Subsequently, the encrypted second data 35 from the second memory 80 read. The comparison device 90 compares the read encrypted second data (bytewise or blockwise) with the encrypted first data 25 , The comparison device 90 now determines the part of the encrypted first data 25 , the part of the unencrypted first data 20 does not already match (in encrypted form) in the encrypted second data 35 is available. This particular part 27 the encrypted first data 25 is from the comparator 90 certainly.

Then the writing device writes 95 exclusively this particular part 27 in the second memory 80 ,

Writing or storing the encrypted first data 25 takes place in the same place where the encrypted second data 35 in the second memory 80 available. Thus, only bytes or blocks of the second data that have changed are replaced. Effectively, therefore, only the data stored relative to the second data already present in the non-volatile second memory is stored 35 have changed. This reduces the number of writes in the second memory 80 ,

To encrypt or decrypt the same key for the first data in a symmetric encryption algorithm 20 / 25 and the second data 30 / 35 used. In an asymmetric encryption method, the same complementary key pair for the first data 20 / 25 and for the second data 30 / 35 used.

3 shows a schematic sequence of an alternative comparison implementation. Here, the plaintext of the first data is compared with the plaintext of the second data. This will be the encrypted second data 35 from the second memory 80 read. These are then processed by the computing device 85 decrypted and stored in the first memory. It is also conceivable that these are stored in another, a third memory.

The comparison device 90 compares the unencrypted first data (bytewise or block by block) with the decrypted second data 30 , Subsequently, only the part of the unencrypted first data 20 by means of the computing device 85 Encrypted in the unencrypted first data 20 and the decrypted second data 30 not identical. It is also conceivable that all unencrypted data 20 be encrypted.

In the following, only or exclusively the part of the encrypted first data is used 25 in the second memory 80 written to the part of the unencrypted first data 20 which is not identical to the decrypted second data 30 is. This means that the comparison of the changed data, the in 2 based on the encrypted data, in 4 based on the non-encrypted (first data) or decrypted data (second data). Only the parts that are different in the first data from the data in the second data are written in encrypted form in the non-volatile second memory.

In both cases (ie when comparing encrypted and unencrypted / decrypted data), only the bytes or blocks will be in the second memory 80 written opposite the already in the second memory 80 existing second data (which is encrypted) have changed. This reduces the number of writes. Thus, the life of the second memory is extended 80 , In addition, the time to store the first data decreases 20 / 25 because effectively less data must be written than when writing all the first data 25 without a comparison, what has changed.

A first type of encryption is the stream encryption and another type of encryption is the block encryption, for example with the Advanced Encryption Standard (AES). The block encryption can be operated in a so-called counter mode, so that also creates a stream encryption. In a block encryption, which is not operated in counter mode, the change of a bit in plain text leads to a far-reaching change of the cipher text or the encrypted data.

4 shows the known from the prior art mode of a block encryption algorithm in the so-called counter-mode. In this case, an initialization vector consists of a random number to be newly selected for each ciphertext linked to a counter, which is incremented with each further block. The initialization vector or counter 60 will with the key 50 Encrypts to an intermediate key 55 to create. This intermediate key 55 is then, for example by means of an XOR operation, with the plain text or first data 20 combined to make the ciphertext or the encrypted first data 25 to win.

The indicated memory system or the indicated method is particularly suitable for scenarios such as car-sharing, in which a large number of changing data is obtained, which usually / in the prior art leads to a high number of deletions or write operations and a fast Aging of the non-volatile second memory 80 leads.

In the described embodiments, encryption in counter-mode was used. Other block encryption algorithms or block ciphers may also be used in accordance with the invention to generate a stream cipher.

LIST OF REFERENCE NUMBERS

LIST OF REFERENCE NUMBERS

20

first data (unencrypted)

25

first data (encrypted)

27

certain part of the encrypted first data

30

second data (decrypted)

35

second data (encrypted)

50

key

55

intermediate key

60

counter

70

storage system

75

first memory

80

second memory

85

computing device

90

comparator

95

Writer

Claims (16)

Method for encrypting first data ( 20 ) in a first memory ( 75 ) and writing the encrypted first data ( 25 ) into a non-volatile second memory ( 80 ), comprising the steps of: encrypting the first data ( 20 ) in the first memory ( 75 ) by means of a stream encryption algorithm or by means of a block encryption algorithm, wherein the block encryption algorithm is preferably operated to generate counter-mode stream encryption; Comparing the encrypted first data ( 25 ) in the first memory ( 75 ) with encrypted second data ( 35 ) in the non-volatile second memory ( 80 ) and determining the part of the encrypted first data ( 25 ) that is not identical to the encrypted second data ( 35 ); and writing only the specific part ( 27 ) of the encrypted first data ( 25 ) from the first memory ( 75 ) into the non-volatile second memory ( 80 ), which is not identical to the encrypted second data ( 35 ). Method for encrypting first data ( 20 ) in a first memory ( 75 ) and writing the encrypted first data ( 25 ) into a non-volatile second memory ( 80 ), comprising the steps of: decrypting encrypted second data ( 35 ) stored in the non-volatile second memory ( 80 ) are stored; Comparing the decrypted second data ( 30 ) with the non-encrypted first data ( 20 ) stored in the first memory ( 75 ) and determining the portion of the non-encrypted first data ( 20 ), which is not identical to the decrypted second data ( 30 ); Encrypt at least the specific part ( 27 ) of the non-encrypted first data ( 20 ), which is not identical to the decrypted second data ( 30 ) is, by means of a stream encryption algorithm or by means of a block encryption algorithm, wherein the block encryption algorithm is operated to generate a counter-mode stream encryption; and writing only the specific part ( 27 ) of the encrypted first data ( 25 ), the part of the non-encrypted first data ( 20 ), which is not identical to the decrypted second data ( 30 ) is in the non-volatile second memory ( 80 ). Method according to claim 1 or 2, wherein as the first memory ( 75 ) a volatile memory such as DRAM, RAM and / or SRAM is used. Method according to one of the preceding claims, wherein as a first step encrypted second data ( 35 ) stored in the non-volatile second memory ( 80 ) and the encrypted second data ( 35 ) and then the decrypted second data ( 30 ) are changed to the non-encrypted first data ( 20 ) in the first memory ( 75 ) to win.  Method according to one of the preceding claims, wherein a symmetric block encryption algorithm is used as the block encryption algorithm.  Method according to one of the preceding claims, wherein a symmetrical stream encryption algorithm is used as stream encryption algorithm. Method according to one of the preceding claims, wherein as the second non-volatile memory ( 80 ) a flash EEPROM memory is used. Storage system ( 70 ) for a vehicle, comprising: a first memory ( 75 ) for storing non-encrypted first data ( 20 ), a non-volatile second memory ( 80 ) for storing encrypted second data ( 35 ), a computing device ( 85 ) for encrypting the first data ( 20 ) by means of a stream encryption algorithm or by means of a block encryption algorithm, wherein the block encryption algorithm is operated in counter-mode to generate a stream encryption, a comparison device ( 90 ) for comparing the encrypted first data ( 25 ) with the encrypted second data ( 35 ) and determining the part of the encrypted first data ( 25 ), which is not identical to the encrypted second data ( 35 ), and a writing device ( 95 ) for writing only the specific part ( 27 ) of the encrypted first data ( 25 ), which is not identical to the encrypted second data ( 35 ) is in the non-volatile second memory ( 80 ). Storage system ( 70 ) for a vehicle, comprising: a first memory ( 75 ) for storing non-encrypted first data ( 20 ), a non-volatile second memory ( 80 ) for storing encrypted second data ( 35 ), a computing device ( 85 ) for encrypting the non-encrypted first data ( 20 ) and to decrypt the encrypted second data ( 35 ) stored in the non-volatile second memory ( 80 ), by means of a stream encryption algorithm or by means of a block encryption algorithm, wherein the block encryption algorithm is operated in counter-mode to generate a stream encryption, a comparison device ( 90 ) for comparing the non-encrypted first data ( 20 ) with the decrypted second data ( 30 ) and determining the portion of the non-encrypted first data ( 20 ), which is not identical to the decrypted second data ( 30 ), and the part of the encrypted first data ( 25 ), the part of the non-encrypted first data ( 20 ), which is not identical to the decrypted second data ( 30 ), and a writing device ( 95 ) for writing only the specific part ( 27 ) of the encrypted first data ( 25 ), the part of the non-encrypted first data ( 20 ), which is not identical to the decrypted second data ( 30 ) is in the non-volatile second memory ( 80 ). Storage system ( 70 ) for a vehicle according to claim 8 or 9, wherein the first memory ( 75 ) is a volatile memory such as DRAM, RAM and / or SRAM. Storage system ( 70 ) for a vehicle according to one of claims 8-10, wherein the computing device ( 85 ) for reading and decrypting the encrypted second data ( 35 ) stored in the non-volatile second memory ( 80 ) are stored for storing the decrypted second data ( 30 ) in the first memory ( 75 ) and for modifying the stored decrypted second data ( 30 ) in the first memory ( 75 ) is designed to extract from the decrypted second data ( 30 ) the non-encrypted first data ( 20 ) in the first memory ( 75 ) to win. Storage system ( 70 ) for a vehicle according to any one of claims 8-11, wherein the block encryption algorithm is a symmetric block encryption algorithm. Storage system ( 70 ) for a vehicle according to any one of claims 8-11, wherein the stream encryption algorithm is a symmetric stream encryption algorithm. Storage system ( 70 ) for a vehicle according to one of claims 8-13, wherein the second non-volatile memory ( 80 ) is a flash EEPROM memory. Motor vehicle with a storage system ( 70 ) according to any one of claims 8-14.  A computer-readable storage medium storing executable machine instructions that cause a computer to implement the method of any one of claims 1 to 7 when executed.

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