DE102009018222A1 - Writing command e.g. single block write command, executing method for use in e.g. terminal in write protected memory section of memory of smart card, involves testing write authorization of entity for writing user data in memory block - Google Patents

Abstract

The method involves receiving a writing command (300) of a terminal (20), where the writing command comprises authentication data (322) and user data (323). Write authorization of an entity is tested for writing the user data in a memory block (15) of a write protected memory section (14), where the memory block is specified by the writing command. The authentication data for testing the write authorization of the entity and the user data are extracted from a user data portion (320) for writing in the memory block. Independent claims are also included for the following: (1) a potable data carrier comprising a memory with a write protected memory section and a control section (2) a terminal comprising a writer.

Description

The The present invention relates to a method on a portable Disk for executing a write command a terminal in a read-only memory section a memory of the disk, as well as such portable data carrier and a terminal.

It is known on a portable equipped with a memory Disk a read-only memory section set up, for example, a protected storage partition or the like, to which a terminal, for example a telecommunications or user terminal, such. B. a Mobile phone, a computer, a laptop, a digital camera or the like, writing only with proof of write permission can access. For this purpose, the disk carries a Authentication of the relevant terminal or his User through and checks if the required write permission is comprised of memory access rights to the terminal or whose users have been assigned.

In this context, the EP 1 673 958 a method for resource management of a mobile terminal, in which the access authorization of a user is checked by an inserted in the mobile terminal SIM mobile card regardless of any sign-on to the mobile network.

The DE 10 2007 050 463 A1 discloses a method for accessing a portable data carrier by means of an access command, which can either be executed as a conventional memory access command in a memory of the data carrier or, if in the access command exists a routing information, are forwarded to a security module and there the execution of security-related functions May have consequences, z. As an authentication, signature or the like. In this case, the routing information and possible additional application information are embedded in the access command such that the access command corresponds to a data communication protocol intended for conventional memory access commands.

It The object of the present invention is to provide a portable Disk read-only Memory section on the one hand as comprehensively as possible against unauthorized write accesses and on the other hand for the Write access triggering instance as transparent as possible perform.

These Task is by a method as well as a data carrier and a terminal with the features of independent Claims solved. In the dependent Claims are advantageous embodiments and developments of the invention.

One Inventive data carrier leads a write access of a terminal in a read-only Memory section of a storage of the disk only off if a write permission of that instance is detected which is the write access by means of one of the terminal Write commands transmitted to the data medium has triggered. This instance can be, for example, the terminal itself or a user logged in on the terminal. According to the invention, such comprises of the relevant instance triggered and from the disk received write command authentication data and user data, wherein a control device of the data carrier based on the authentication data checks if the instance has the required write permission owns the payload into a memory block of read-only Memory section to write, given by the write command becomes.

The write permission to check from the volume according to the invention does not concern only a principal or unspecific write authorization of the instance triggering the write command, but is also dependent on the memory block in question and the user data to be written. In the test of Write authorization, therefore, enters into three criteria that are immediate can be checked using the write command, so the exam's write permission is solely due of the write command is possible and more login or Authentication steps can be avoided. To this On the one hand, writing permission can be much more specific and be targeted and, on the other hand, arise no further requirements for the triggering instance, z. B. to a user of the terminal.

The invention allows write accesses to individual memory blocks of a read-only memory partition of any portable data carrier, eg. As a mobile card, secure multimedia card or the like to check for a write permission. This allows a manufacturer of such portable media to set up a read-only storage partition there whose contents can not be modified or deleted by end users, e.g. By formatting the memory partition or the like. In this case, it is particularly expedient, apart from a read-only memory partition with protected contents, also to protect that memory area of the memory in accordance with the invention, which comprises the partition table, so that the memory also can not be repartitioned.

Of the Exchange of (write) commands between the terminal and the disk is usually in accordance with a agreed between the terminal and the disk Data communication protocol, in particular the command format and thus the structure of a write command and its interpretation pretends. Usually includes a write command, such as other commands also, a header data portion and a payload portion. The header data share generally includes administrative data, such as. B. Command type data or memory address data used for interpretation of the command while the payload portion the actual to be written into the memory of the volume User data includes. When processing a write command so initially only interprets the data of the header data share, while the data of the user data portion without further testing user data to be transferred as the argument of the write command represent.

According to the invention however, the payload portion is adjacent to the read-only memory portion user data to be written also the authentication data for testing the write authorization of the instance concerned, so that the control device Not only the header data but also the user data portion of the write command regarding the authentication data. As a result, a writing device of the terminal embeds the authentication data in such a way in the Nutzdatenanteil that on the one hand the specifications of the agreed data communication protocol and on the other hand the additional authentication data the user data portion of the control device reproducibly extracted can be. A received write command is issued by the controller of the disk so not - like it would provide the data communication protocol immediately rather, it will be checked first, whether authentication data is present in the user data part in order to this if necessary further processing.

By the embedding of the per se not protocol Authentication data in the payload part is an inventive Write command in the read-only memory section in a protocol-based write command embedded. In this way, when implementing the invention Procedure the agreed data communication protocol and insofar also adopted the familiar command structures unchanged become.

Preferably the authentication data comprise an authentication key and a permission table address pointing to a permissions table refers to, which is present in a memory of the volume. The controller checks the write permission of Instance then by the authentication key located in the authentication data extracted and matched with a reference key the instance in question via the authorization table assigned.

in this connection is the one associated with the instance through the entitlement table Reference key preferably a symmetric cryptographic key, during the authentication key contained in the write command is an identical symmetric comparison key, the control device with the symmetrical reference key from the entitlement table. Unless the comparison key and the reference key do not match, the processing of the write command is aborted because the relevant Instance the required write permission (in the form of a correct Vergleichschlüssels) obviously does not possess.

In another embodiment uses the control device the symmetric reference key of the instance to the user data reference test data present in the memory command to produce, for. B. by encrypting the user data with the reference key, so that this with comparison check data can be compared in the write command as Authentication key present. Again, the Processing of the write command aborted when the comparison check data and the reference check data do not match, because the instance concerned either does not have the correct symmetric Comparison key for generating the comparison check data owns or transfers the wrong user data with the write command were, z. B. due to a manipulation of the user data by a malicious software installed on the terminal, eg. B. a Trojan, virus or the like.

The introduced in the payload portion of the write command Vergleichsprüfdaten z. B. a MAC identifier ("Message Authentication Code"), which corresponds to the symmetrically encrypted user data. In addition to the user data and other data can go into such a MAC identifier, z. B. the memory address data or other authentication or identification data of the user to which the controller has access, for. B. because they are stored in the entitlement table. If the control device has the MAC identifier present as authentication data with the reference key assigned to the instance by encrypting the user data (and given If necessary, it can be ensured that the instance triggering the write command has a correct comparison key and that the user data are unmanipulated.

Preferably is next to checking the authentication data of the write command also checked whether a write permission on the memory block given by the memory address data of the write command refers. For this purpose, it is verified whether the predetermined by the memory address data Memory block of the instance concerned via the authorization table assigned. If the instance so the possession or knowledge of the correct authentication key can prove the authentication data and you can see the relevant Memory blocks assigned via the authorization table are, the controller causes a writing of the user data in the relevant memory block.

Preferably the controller checks for the presence of authentication data in the payload portion of the write command only if the write command a write access to the read-only memory section concerns, for example, a read-only partition of the memory or the partition table. If based on the in the Header data portion of existing memory address data is detected, that the memory command has memory access to another, non-read-only memory section is concerned the user data part is completely interpreted as user data and a regular, protocol-based write command executed. If present in the header data share However, memory address data has a memory access to the read-only Display memory section, there is a presence of authentication data is checked in the payload portion and the received memory command becomes as an embedded write command in the read-only Memory section treated.

in the In connection with the present invention may be a write command triggering instance, for example, be a user of the terminal, which is registered on this. Similarly, it may be at the instance also act around the terminal itself or with the one Terminal connected via a data communication network another device, such as a server on the Internet or similar. Preferably, the disk or its control device configured such that such Instance, before sending a write command through the terminal on the disk can trigger, opposite To log on to the disk by being authenticated by it becomes. As part of this authentication of the instance by the disk can a new symmetric cryptography key between the instance and the volume to be negotiated on the one hand as reference key in the authorization table and on the other hand by the entity as a comparison key is used. It is also possible that as comparison / reference key an existing symmetric cryptographic key is selected and the authenticated instance over the entitlement table is assigned. In principle it is not It is absolutely necessary for an instance to stand up to the Periodically logs and authenticates volumes becomes. Rather, an unregistered or unauthenticated Instance of the symmetric cryptography key as Comparison / reference keys are assigned to this or another instance in the previous login process or authentication process has been assigned. It is also possible that each instance or at least groups of instances of the same, fixed symmetric cryptography key is assigned.

The Authentication of the instance by the disk can this happen in a conventional manner, for example by checking if the instance is a global or disk individual Knows secret, for example, by a personal Identity number (PIN) or other identifier that the instance is presented to the volume, with a Reference PIN or a reference identifier is compared to the the data carrier for the relevant instance is.

Preferably For example, a memory command includes payload data in a data volume essentially corresponds to that of a memory block, so that with a write command exactly one memory block can be written. The maximum data volume that can be written by a write command User data is limited by the user data portion, the specified by the agreed data communication protocol. However, since usually the data volume of the user data portion of a write command corresponds to that of a memory block, reduces due to the deposited in the user data share Authentication data the possible payload volume so, that described with a write command not an entire memory block can be, but requires two memory commands for this purpose whose payload data is written to the memory block in combination become.

In this embodiment, in which the payload data to be written into a memory block is divided into two write commands, it is necessary to define an order according to which the payload data the two write commands are written in the relevant memory block. For this purpose, a write command preferably includes in its payload additional Re construction data indicating the manner in which the payload of individual write commands to combine and arrange in the memory block in question. For example, the reconstruction data of the respective memory commands can specify an ordinal number which indicates the order of the user data in the memory block. Preferably, the write authorization of the instance is checked for both triggered write commands.

About that In addition, a write command can also payload for several consecutive memory blocks that are common written to the multiple memory blocks as soon as the write authorization of the instance based on the authentication data is detected. Likewise, a write command can have several write command sections each comprising at least authentication data and payload data include, so for each write command section separately It can be checked if the instance has write permission the relevant user data based on the respective authentication data is present. In the case of write commands, several in read-only Memory section sequential memory blocks relate, the controller can this also independently combine or compress by adding redundant control and management data, z. From the respective header data portions.

If a write command payload for several different Contains memory blocks, so may for testing the write authorization uses a single authentication date which is calculated from all user data of the write command.

Further Features and advantages of the invention will become apparent from the following Description of embodiments according to the invention and other alternative alternatives with the drawings that show:

1 an arrangement comprising a portable data carrier according to the invention and a terminal;

2 a preferred construction of a write command according to the invention;

3 a flowchart of a preferred method sequence according to the invention; and

4 a sketch of a particular embodiment of the method according to the invention.

1 shows a data communication arrangement in which a terminal 20 writing on a memory 12 a portable volume 10 by means of a write command 300 accesses. The portable data carrier 10 In this case, the components customary for such devices, such as a processor (not shown), comprise a bus system with a data communication interface 16 , a memory device comprising a permanent ROM memory with operating system (not shown), a non-volatile memory 12 For example, a flash memory or the like, as well as a volatile RAM memory (not shown). In the non-volatile memory 12 is a read-only memory section 14 For example, a read-only partition and a non-read-only memory section 18 furnished, z. B. another partition of the memory 12 , A read-only partition table (not shown) of the memory 12 in which the different partitions 14 . 18 of the non-volatile memory 12 are usually in a first memory block of the memory 12 created so that the read-only memory section 14 neither directly nor via the partition table can be manipulated uncontrolled or deleted.

In particular, the data carrier comprises 10 a control device 11 , z. For example, a memory controller that has a write command 300 from the terminal 20 receives and processes. Further, in the non-write protected memory section 18 a preferably secured memory area 13 set up in which security-relevant data are stored, for. B. a permission table 19 in which for the control device 11 known users or for others on the read-only memory section 14 accessing instances, reference key 17 (REF), the authentication of the user or the respective instance in a write access to the read-only memory section 14 serve.

The controller may distinguish and process at least two different types of write commands, namely, conventional write commands into the non-read-only memory section 18 according to a between the disk 10 and the terminal 20 agreed data communication protocol are built and processed, and embedded write commands 300 in the read-only memory section 14 which have a command structure different from the conventional write commands, but which are transparently embedded in a conventional write command according to the agreed data communication protocol.

In a conventional write access of terminal 20 in the non-volatile memory 12 generates a writing device 22 of the terminal 20 a write command with a header data share 310 (HERD) for administrative data and a payload 320 (LORD) for user data and transmits it via the data communication interfaces 23 and 16 to the controller 11 of the disk 10 that is from the header data share 310 a command type and a memory address of the memory section 18 takes, at the in the Nutzdatenanteil 320 present user data should be stored. This memory access is provided by the controller 11 block-oriented performed, ie in the payload portion 320 present user data are completely in a memory block of the memory section 18 written, where in the Nutzdatenanteils 320 for user data available data volume is matched to the respective memory block size.

The command structure of a conventional write command is specified by the agreed data communication protocol. Depending on the type of volume 10 For example, the agreed data communication protocol may be an SD protocol or an MMC protocol, as long as the data carrier is the same 10 is an SD memory card ("Secure Digital Memory Card") or an MMC ("Multimedia Card") memory card. Unless it is the disk 10 is a conventional smart card or a smart card that with a smart card terminal as a terminal 20 For example, the data communication protocol may be the T = 0 or T = 1 protocol according to ISO 7816-3 act.

However, the write access is an embedded memory command 300 in the read-only memory section 14 , is from the controller 11 a special authentication or authentication method based on authentication data 322 (AUTH) performs the writing device 22 in the payload portion 320 of the writing command 300 has embeds. After receiving a write command 300 checks the control device 11 First, whether it is an embedded write command 300 is. This can either be recognized by the fact that a memory block 15 in the read-only memory section 14 or that in the payload portion 320 Authentisierensdaten 322 available. If neither a memory block 15 in the read-only memory section 14 still authentication data 322 can be detected, the control device 11 the write command as conventional write access in the non-write protected memory section 18 interpret, in which the entire data volume of the user data portion 320 is interpreted as payload. If, however, an embedded write command 300 is in the read-only memory section, this is from the controller 11 processed separately as described below.

At a write command 300 in the read-only memory section 14 embeds the writing device 22 of the terminal 20 the required authentication data 322 in the payload portion 320 a, that the control device 11 the embedded authentication data 322 from the received payload 320 to extract for further examination. By embedding authentication data 322 in a user data portion 320 , which is provided according to the data communication protocol used only for pure payload, becomes a so-called "tunnel" between the terminal 20 and the disk 10 established, in which the agreed data communication protocol is also used for the transmission of non-protocol data, namely the authentication data 322 , The writing device 22 and the controller 11 are thus coordinated so that this "tunnel" can be operated by coordinated embedding and extraction of non-protocol data.

2 outlines the structure of a conventional write command and a write command embedded in it 300 in the read-only memory section 14 , One or more such write commands are from the controller 11 interpreted and processed as a data telegram. Like a conventional write command also includes an embedded write command 300 a header data share 310 who is responsible for the interpretation and execution of the write command 300 required tax and administrative data, as well as a user data share 320 , which includes in a conventional write command only uninterpreted payload as an argument of the write command.

The header data share 310 this usually includes command type data 311 (CMD) indicating the type of the intended command, in the case of a write command z. "SingleBlockWrite" or "MultipleBlockWrite", as well as address data 312 (ADR), which is a memory block 15 in the read-only memory section 14 address. In the user data portion 320 be next to the payload 323 (DATA) also introduced further data, which is for a write access in the read-only memory section 14 necessary. These include in addition to the already mentioned authentication data 322 also reconstruction data 321 (REC), which are needed to payload 323 various write commands 300 in an envisaged manner in the read-only memory section 14 or in the memory block 15 to arrange. Finally, the payload includes 320 also the actual user data 323 as an argument of the embedded write command 300 in the of the address data 312 specified memory block 15 are to be registered. Since the user data share 320 now also includes control data, namely the reconstruction data 321 and authentication data 322 , is at an embedded write command 300 the data volume of the user data 323 reduced compared to a conventional write command, so that in an embedded write command 300 the data volume of the user data 323 is less than that of a memory block 15 ,

3 outlines a three-level authentication method by the controller 11 is being processed to a user who has a write-down 300 in the read-only memory section 14 and the write command 300 to authenticate yourself. Here, first of all, in a step S1, an authentication of the user is performed, which is the write command 300 over the terminal 20 (VERIFY USER), followed by a verification of the write command in step S2 300 through the authentication data 322 (VERIFY CMD) and in step S3 a verification as to whether the memory block in question 15 the user is available for write access (VERIFY BLOCK). If the three verification steps have been successful, finally, in step S4, the payload 323 in the memory block 15 written (WRITE DATA).

In a the in 3 sketched process upstream step generates the terminal 20 or its writing device 22 an embedded write command 300 by adding a conventional header data share 310 and a payload 320 be provided, wherein the payload portion 320 reconstruction data 321 , Authentication data 322 and user data 323 includes. The authentication data 322 For example, a storage address of the entitlement table 19 As well as a symmetric cryptographic key include the user of the Steuerein direction 11 as a comparison key 24 Assigned (CMP) and as a reference key 17 (REF) in the entitlement table 19 was deposited. The comparison key 24 and the reference key 17 For example, it may be negotiated according to a known key generation method, or it may be an already existing symmetric cryptographic key from the controller 11 to be selected. Likewise, an immutable cryptographic key valid for all users or for a particular group of users may be used. Moreover, it is also possible that not for each user an individual symmetric cryptographic key as comparison or reference key 21 . 17 is determined, but that a symmetric cryptography key 21 . 17 has a predetermined time validity period and for a new user only then another symmetric cryptography key 21 . 17 must be determined if this period of validity has expired. Here, a user can also use a symmetric cryptographic key as comparison or reference key 24 . 17 assigned to a previous user.

A user always gets a (new or known) symmetric cryptographic key as a comparison or reference key 24 . 17 assigned when in step S1 opposite the control device 11 authenticated. Thus, a user can have the comparison / reference key assigned to him 24 . 17 keep it until it reappears to the controller 11 authenticate them and give them a new comparison / reference key 24 . 17 assigns. This authentication can be carried out, for example, by checking a global or data-carrier-specific secret of the user, for example by comparing a comparison secret provided by the user, eg. B. a personal identification number (PIN), a one-time password or the like, with egg nem the control device ( 11 ) present reference secret, the z. In the authorization table 19 or in another secure storage area of the volume 10 can be deposited.

In step S2, the controller compares 11 those from the received, embedded write command 300 extracted authentication data 322 , or the comparative key present therein 24 , with that in the permissions table 19 reference key assigned to this user 17 , Alternatively it is possible that the writing device 22 of the terminal 20 as authentication data 322 a MAC identifier ("Message Authentication Code") in the payload portion 320 that comes from the symmetric comparison key 24 and at least the user data to be written 323 represents derived comparison check data. For example, such a MAC identifier can be obtained by symmetrically encrypting the payload 323 be generated. In this case, the controller checks 11 the received authentication data 322 (the comparison check data) by encrypting the in the payload portion 320 present user data 322 with the in the authorization table 19 present reference key 17 and comparing the encryption result (the reference check data) with the authentication data 322 (the comparison check data), If there is a match, the write command is valid 300 or the write represented by it access to the read-only memory section 14 as authenticated.

In the in 4 detailed authorization table 19 in a secured storage area 13 is created is the respective user, who is the respective write command 300 has triggered, via a unique user identification number (UID) or the like of the negotiated or selected reference key 17 assigned. The user identification number may be from the writer 22 z. B. in the header data share 310 or in the authentication data 322 of the writing command 300 be introduced. In addition to the reference key 17 can in the permission table 19 also individual memory blocks or larger memory areas of the read-only memory section 14 be given to a user in principle for write accesses in the read-only memory section 14 be available. In addition to the verification steps S1 and S2, it is accordingly checked in step S3 whether the data stored by the memory address data 312 certain memory block 15 in the authorization table 19 associated with the user in question. Of course, steps S1 to S3 may also be performed in any other convenient order, e.g. For example, the verification of the memory address data 312 in step S3 also before the verification of the authentication data 322 done in step S2. In any case, the payload 323 however, only in the specified memory block 15 written when all verification steps S1 to S3 have been completed successfully.

4 finally illustrates a particular embodiment, with which the already related 2 can be taken into account that by embedding a write command 300 , with which a write access to the read-only memory section 14 is executed, only a data volume of user data 323 in the payload portion 320 available behind the data volume of a memory block 15 remains.

For a data volume of a memory block 15 in the read-only memory section 14 512 bytes (512 bytes LORD) can be used by the writer 22 the corresponding user data of 512 bytes in two user data packets 323 each of 256 bytes (256 bytes DATA) and each as user data 323 in separate write commands 300 contribute. Here is the writing device 22 in the payload portion 320 additional reconstruction data 321 that determine in what way the controller 11 of the disk 10 the two user data packets 323 when writing to the memory block 15 must combine. For example, as reconstruction data 321 in 4 the two statements "LO" (or "low") and "HI" (or "high") are made, which determine that the LO payload portion 323 in the memory block 15 before the HI user data share 323 should be stored. As the control device 11 both write commands 300 in the in 3 individually scrutinized way are in both embedded write commands 300 at least the address data 312 (# adr1) identical and the authentication data 322 (CMP1) differ only if they are different from the comparison key 24 are also dependent on other data, eg. B. from the variable user data packets 323 ,

In the in 4 In the illustrated example, both write commands each include the comparison key 24 of the user in question with the one in the authorization table 19 for the user with the user identification number UID = 1 specified reference key 17 matches. There is also the entitlement table 19 for the verification step S3 also memory areas or memory blocks (eg # adr1 to #adrN for UID = 1), which can be described in principle by the relevant user, provided that the required verification steps S1 and S2 have been successfully completed.

In addition to the previously described "SingleBlockWrite" spell commands 300 with which only one memory block 15 is described, other types of write commands are conceivable according to the in the 1 to 4 sketched principle are generated, constructed and processed. For example, the controller may 11 also "MultipleBlockWrite" spell commands 300 process multiple blocks of memory. Such a "MultipleBlockWrite" write command 300 can z. B. a header data share 310 and several user data shares 320 with individual authentication data 322 and user data 323 include. The user data shares 320 are then from the controller 11 separately based on the respective authentication data 322 checked and the relevant user data 323 are consecutively written to a plurality of consecutive memory blocks that match the one by the matching memory address data 312 specific memory block 15 kick off. Likewise, a "MultipleBlockWrite" write command 300 also comprise a plurality of write command sections, each in turn a full head portion 310 and a full payload 320 and tested separately. Finally, a "MultipleBlockWrite" write command 300 also a user data share 320 having only one authentication record 322 and several payload records 323 includes. Again, all payload records 323 by the verification of the authentication data 322 verified at the same time.

If a write command payload for several different Contains memory blocks, so may for testing the write authorization uses a single authentication date which is calculated from all user data of the write command.

Furthermore, the control device 11 also several "SingleBlockWrite" write commands 300 , which relate to successive memory blocks, to one of the above-mentioned "MultipleBlockWrite" write commands 300 to save redundant control and administration data, e.g. B. header data shares 310 and / or authentication data 322 ,

At the conclusion of a write access, the writer 22 of the terminal 20 the success of the embedded write command through a regular read into the memory block concerned 15 to verify. Furthermore, it is possible to enter the authentication data 322 a symmetric comparison key 24 and to introduce a MAC identifier, wherein the write authorization based on the comparison key 24 verifying and verifying the MAC identifier, the tamper-free transmission of the write command 300 is ensured. Of course, the user data must 323 not in plain text in the user data portion 320 but may also be in encrypted and obfuscated form, for example as a MAC identifier or the like.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - EP 1673958 [0003]
• - DE 102007050463 A1 [0004]

Cited non-patent literature

• - ISO 7816-3 [0034]

Claims (20)

Method on a portable data carrier ( 10 ), in which a write command ( 300 ) of a terminal ( 20 ) into a read-only memory section ( 14 ) of a memory ( 12 ) of the data carrier ( 10 ) is only executed (S4), provided that a write authorization of a write command ( 300 ) triggering instance, characterized in that an authentication data ( 322 ) and user data ( 323 ) comprehensive write command ( 300 ) of the terminal ( 20 ) and based on the authentication data ( 322 ) a write authorization of the instance for writing the user data ( 323 ) in one of the write command ( 300 ) predetermined memory block ( 15 ) of the read-only memory section ( 14 ) (S2). Method according to claim 1, characterized in that a header data part ( 310 ) and a user data portion ( 320 ) comprehensive write command ( 300 ) into the read-only memory section ( 14 ) of the memory ( 12 ) according to one between the terminal ( 20 ) and the data medium ( 10 ) received data transmission protocol, wherein from the user data portion ( 320 ) the authentication data ( 322 ) for checking the write authorization of the instance and the user data ( 323 ) for writing to the memory block ( 15 ) are extracted. Method according to claim 2, characterized in that from the authentication data ( 322 ) an authentication key and an authorization table ( 19 ) in a memory ( 12 ) of the data carrier ( 10 ), wherein the write authorization of the instance by means of a comparison of the authentication key with one of the instance via the authorization table ( 19 ) associated reference key ( 17 ) is checked. Method according to Claim 3, characterized in that a symmetrical comparison key ( 24 ) as the authentication key with the symmetric reference key ( 17 ) is compared (S2), wherein the processing of the write command ( 300 ) is aborted if the comparison key and the reference key ( 17 ) do not match. Method according to claim 3, characterized in that from the user data ( 323 ) and the symmetric reference key ( 17 ) Reference check data are generated and the reference check data is compared with comparison check data as the authentication key (S2), whereby the processing of the write command ( 300 ) is aborted if the comparison check data and the reference check data do not match. A method according to claim 5, characterized in that the reference check data are generated by the user data ( 323 ) with the symmetric reference key ( 17 ) are encrypted. Method according to one of claims 3 to 6, characterized in that from the header data share ( 310 ) of the write command ( 300 ) Memory address data ( 312 ) and the payload ( 323 ) in the of the memory address data ( 312 ) predetermined memory block ( 15 ), provided the write authorization of the instance is based on the authentication data ( 322 ) is detected. Method according to Claim 7, characterized in that the processing of the write command ( 300 ) is aborted, provided that the memory address data ( 312 ) predetermined memory block ( 15 ) in the authorization table ( 19 ) is not assigned to the instance (S3). Method according to one of claims 3 to 8, characterized in that a write command triggered by an instance ( 300 ) from the disk ( 10 ) is executed only if the instance of the volume ( 10 ) (S1), whereby for a authenticated entity a new reference key ( 17 ) or an existing reference key ( 17 ) and the authenticated entity in the entitlement table ( 19 ). Method according to one of Claims 3 to 9, characterized in that for an entity which is dependent on the data carrier ( 10 ), a new reference key ( 17 ) or an existing reference key ( 17 ) and the authenticated entity in the entitlement table ( 19 ) and an instance that is not facing the volume ( 10 ), a reference key ( 17 ) that has already been assigned to this instance. Method according to claim 9 or 10, characterized in that an instance of the data carrier ( 10 ) is authenticated if a comparative secret of the instance with one in a memory ( 12 ) of the data carrier is in agreement with the reference secret (S1). Method according to one of claims 2 to 11, characterized in that a write command of the terminal ( 20 ) into one of the read-only memory section ( 14 ) different memory section ( 18 ) of the memory ( 12 ) is processed in accordance with the agreed data transfer protocol by dividing the total payload ( 320 ) as user data ( 323 ) is interpreted. Method according to one of claims 1 to 12, characterized in that in the predetermined memory block ( 15 ) of the read-only memory section ( 14 ) User data ( 323 ) of at least two write commands ( 300 ), the payload data ( 323 ) of the at least two write commands ( 300 ) in a predetermined manner in the predetermined memory block ( 15 ), provided that for each of the at least two write commands ( 300 ) a write authorization of the instance for writing the respective user data ( 323 ) in the given memory block ( 15 ) is detected. A method according to claim 13, characterized in that from the respective user data shares ( 320 ) of the at least two write commands ( 300 ) each reconstruction data ( 321 ) and the payload ( 323 ) of the at least two write commands ( 300 ) by the reconstruction data ( 321 ) predetermined order in the predetermined memory block ( 15 ) to be written. Method according to one of claims 1 to 14, characterized in that an authentication data ( 322 ) and user data ( 323 ) for at least two memory blocks ( 15 ) comprehensive write command ( 300 ), the payload ( 323 ) starting with the given memory block ( 15 ) are written in at least two consecutive memory blocks, if based on the authentication data ( 322 ) a write authorization of the instance for writing user data ( 323 ) in the given memory block ( 15 ) of the read-only memory section ( 14 ) is detected. Method according to one of claims 1 to 15, characterized in that a write command ( 300 ) with at least two respective authentication data ( 322 ) and user data ( 323 ) is received, wherein for each of the at least two write command sections is checked separately whether a write permission of the instance for writing the respective user data ( 323 ) of the respective write command section into a memory block individually predetermined by the relevant memory command section ( 15 ) is present. Method according to one of claims 1 to 16, characterized in that a write command ( 300 ) received from the terminal ( 20 ) or a user of the terminal ( 20 ) or from one with the terminal ( 20 ) connected further device and a write permission of the terminal ( 20 ) or the user of the terminal ( 20 ) or the with the terminal ( 20 ) connected further device is checked. Portable disk ( 10 ), comprising a memory ( 12 ) with a read-only memory section ( 14 ) and a control device ( 11 ), which is set up, a write command ( 300 ) one with the data medium ( 10 ) connected terminal ( 20 ) into the read-only memory section ( 14 ) only if the control device ( 11 ) a write permission of the write command ( 300 ) triggering instance, characterized in that the from the terminal ( 20 ) received write command ( 300 ) Authentication data ( 322 ) and user data ( 323 ) and the control device ( 11 ) is further set up on the basis of the authentication data ( 322 ) a write authorization of the instance for writing the user data ( 323 ) in one of the write command ( 300 ) predetermined memory block ( 15 ) of the read-only memory section ( 14 ) to consider. Disk ( 20 ) according to claim 18, characterized in that the control device ( 11 ) is arranged to carry out a method according to one of claims 1 to 17. Terminal ( 20 ), characterized by a writing device ( 22 ), which is set up an authentication data ( 322 ) and user data ( 323 ) comprehensive write command ( 300 ) in such a way and to a data carrier ( 10 ) according to one of claims 18 or 19, that the data medium ( 10 ) based on the write command ( 300 ) can perform a method according to any one of claims 1 to 17.