A kind of condition that need not the addressing mandate receives combination control method
Technical field
The invention belongs to the television broadcasting condition and receive the field, relate in particular to a kind of condition that need not the addressing mandate and receive combination control method.
Background technology
In " digital television broadcasting condition receiving system standard " (exposure draft) of SARFT(The State Administration of Radio and Television) condition being received (Conditional Access is called for short CA) is to describe like this: " the condition reception is meant a kind of like this technological means; it only allows that authorized users uses a certain business, and unwarranted user can not use this business.Condition receiving system is realized the system of this function just." so-called business refers generally to transmit as the master data of usually being made up of video, audio frequency, captions, other data etc. that program offers the user and flow TS (Transport Stream).
The CA condition receiving system is a comprehensive system, integrated multiple technologies, comprise system management technologies, network technology, scrambling-descrambling technology, encryption and decryption technology, Digital Television encoding and decoding technique, digital multiplexing technology, receiver technology, smart card techniques etc., also relate to communication management application technology such as user management, program, toll administration simultaneously.Closely-related with the fail safe that transmits stream TS is scrambling-descrambling technology and encryption and decryption technology, wherein adds descrambling and is meant that mainly utilizing certain dynamic control information to change transmits the encryption and decryption signal processing that flows some characteristic of TS; Encryption and decryption mainly refers to the encryption and decryption to dynamic control information.
Dynamic control information produces in broadcast head end, is used for broadcast head end and carries out the transmission stream TS that the scrambling processing forms scrambling to expressly transmitting stream TS, and transmission stream TS and the dynamic control information ciphertext with scrambling is sent to receiving terminal by multiple transmission form then.Obtain expressly dynamically control information through the receiving terminal of authorizing after with dynamic control information decrypt ciphertext, the transmission stream TS that utilizes expressly dynamically control information to finish scrambling carries out scramble process, recovers and expressly transmits stream TS.
Consideration technology and managerial fail safe, dynamically the deciphering of control information generally separates with receiving terminal, independently carries out in the security module at one.Smart card is widely used on the receiving terminal apparatus of condition receiving system as the information carrier of a kind of convenience, safety, and the conditions such as key storage, dynamic control information deciphering that realize receive controlled function.
The CA condition receiving system is the core technology safeguards system that Digital Television receives control, can manage control to digital TV broadcasting service according to time, channel and program according to different situations.At user side, unwarrantedly can not carry out descrambling, and can't watch this program scrambled program.It is the concrete application of present information encryption technology at digital TV field that condition receives, and has realized the classification and the management of program and business information on the one hand; The condition that can realize program on the other hand receives.
Condition at present commonly used receive control device be utilize dynamic control information promptly add/descrambled control words CW (ControlWord) carries out scrambling and handles expressly transmitting stream TS in broadcast head end, inverse process as scrambling, add in the receiving terminal utilization/descrambled control words CW carries out corresponding scramble process to the transmission of scrambling stream TS, recovers and expressly transmit stream TS.
Add/descrambled control words CW generates by scrambling control word generator CWG (Control Word Generator), in order to guarantee to transmit the fail safe of stream TS, add/descrambled control words CW should have dynamically and two characteristics at random at least.So-called dynamically be meant add/descrambled control words CW will be according to certain Crypto Period CP (Crypto Period) dynamic change; So-called be meant at random add/descrambled control words CW be difficult to expect very at random or pseudo random sequence.
To the scrambling and the identical control word of the general use of scramble process that transmits stream TS, promptly said here adding/descrambled control words CW, add/descrambled control words CW generally is sent to receiving terminal by the part as Entitlement Control Message ECM or ECM behind the crypto-operation with encrypted test mode.Having the receiving terminal of receive authorizing can obtain adding/descrambled control words CW expressly by the key computing, with adding expressly/descrambled control words CW the scrambling of receiving is transmitted stream TS and carries out corresponding scramble process and obtain expressly transmitting and flow TS.
If adopt the smart card condition of carrying out to receive control at receiving terminal, smart card may have to receive authorizes, and also may not receive mandate.During the typical case uses at present smart card mandate or cancellation authorization message are included among the Entitlement Management Message EMM (Entitlement Management Message) with the ciphertext form usually, by broadcast head end with independent addressing or divide the mode of group addressing to send to specific receiving terminal, thereby change the authorising conditional of receiving terminal.
What broadcast head end sent does not exist the problem of transmission bandwidth and efficient at the ECM Entitlement Control Message of all receiving terminals.But for the information that sends with addressing system, for example authorize or cancel the EMM Entitlement Management Message of mandate at specific receiving terminal, in unidirectional transmission system owing to there is not the feedback information of receiving terminal, to guarantee effectively that receiving terminal can receive customized information, require broadcast head end to take turns repeatedly and broadcast based on certain probability.Customized information will become a kind of increment information like this, and its data volume will increase along with the increase of number of users.And can imagine that the customized information that wheel is broadcast in the most of the time is not received the terminal reception and uses.On the contrary, legal receiving terminal can not in time receive customized information because the available machine time is short or start is not frequent.Under the transmission bandwidth condition of limited, personalized increment information is the technical bottleneck that exists in the unidirectional condition receiving system.
Wireless or cable TV and computer condition receiving system generally adopt smart card to receive the security control means as the condition of receiving terminal condition of acceptance.The service condition of corresponding secret key is controlled by its inner static state information in the at present common condition reception intelligent card, just might change after only receiving personalized Entitlement Management Message EMM.Under the situation that does not have Entitlement Management Message EMM, can use the ECM Entitlement Control Message, can not use the ECM Entitlement Control Message, the on-line setup of internal authorization state information or revise then requires broadcast head end with separately or divide the form of group addressing to send personalized ciphertext EMM Entitlement Management Message and set or revise.
Summary of the invention
Basic ideas of the present invention are to comprise the dynamic condition receiving control information in Entitlement Control Message ECM, the dynamic change of the inner condition of acceptance of safety devices such as combination by conditional information and random information and receiving terminal smart card is with a kind of fail safe of high efficiency control method guaranteed conditions receiving system.Its main feature is that broadcast head end can be finished the dynamic control and the modification of the condition of acceptance of receiving terminal in real time only by Entitlement Control Message ECM.Like this, because Entitlement Control Message ECM is not an increment information, can use for all legal receiving terminals, can guarantee that receiving terminal receives Entitlement Control Message ECM very soon after start, overcome the bandwidth bottleneck that increment Entitlement Management Message EMM information wheel is broadcast, thereby increase substantially the information transfer efficiency of condition receiving system and simplify the workload of broadcast head end addressing play authorization management system EMM.
Technical scheme of the present invention is: a kind of condition that need not the addressing mandate receives combination control method.It is characterized in that: comprise the Combination Control information that condition receives among the Entitlement Control Message ECM (Entitlement Control Message) that the broadcast head end equipment of CA (Conditional Access) condition receiving system sends, Combination Control information is combined to constitute by conditional information that does not have randomness and random information with randomness and is added/associated data of descrambled control words CW (Control Word) computational methods, wherein conditional information is the condition receiving control information that is associated with effective time of reception section and/or time quantum, the smart card of receiving terminal utilizes key to be associated with conditional information in the Combination Control information, the phase related control information of smartcard internal is carried out dynamically relatively or upgrades, according to dynamically relatively or the result who upgrades, whether decision carries out certain crypto-operation processing to Entitlement Control Message ECM or Combination Control information wherein, obtain correct adding/descrambled control words CW, for receiving terminal the scrambled data that receives is transmitted stream TS (Transport Stream) and carry out descrambling.
The Combination Control information that comprises conditional information and random information that the broadcasting leading portion equipment of condition receiving system is sent, by the receiving terminal smart card carry out that dynamic condition is judged and the condition renewal after, can adopt certain block cipher, for example DES or 3DES algorithm, carrying out computing is added/descrambled control words CW, if the length of Combination Control information surpasses the data length of block cipher, can adopt the block chaining mode for example the mode cryptographic calculation of CBC (CipherBlock Chaining) cryptographic block link added/descrambled control words CW.
Add/calculating of descrambled control words CW can finish in safety device inside such as smart cards, by smart card to the combination condition information processing, guaranteed on the one hand the fail safe of the condition of acceptance control of receiving terminal, guaranteed by random information on the other hand to add/fail safe of descrambled control words CW by conditional information.
The key that is associated with conditional information in the described smart card can be a key, also can be that two or more keys are associated with time period and/or time quantum conditional information in the conditional information respectively.With calculating add/key of descrambled control words CW is associated with time period and/or time quantum conditional information in the conditional information respectively, at first relatively whether the current time is in the log file term of validity of first cipher key associated, if exceeded the term of validity, then stop follow-up calculating process and provide error message, if the current time in the log file term of validity of first cipher key associated, then carries out conditional information and two data blocks of random information to obtain intermediate cryptographic result data piece after twice encrypted url computing with first key; Log file to second cipher key associated carries out subtraction then, if overflow, then stops follow-up calculating process and provides error message, if do not overflow, then intermediate cryptographic result data piece is added/descrambled control words CW after with second secret key encryption.
The scrambling system of broadcast head end equipment and the smart card of receiving terminal can be used in combination following four kinds of time periods and the time quantum condition receives control:
1) use the time period condition relevant to receive control mode separately with the term of validity;
2) use the time quantum condition relevant to receive control mode separately with the actual reception time or the consumption amount of money;
3) use two kinds of conditions to receive control mode simultaneously;
4) two kinds of conditions reception control modes are not used.
Selection for the Combination Control mode of time period and/or time quantum both can be provided with by the scrambling system of broadcast head end, can be provided with by the smart card of receiving terminal again, wherein, can change at any time by the controlled condition of broadcast head end setting, all effective to all receiving terminals; The controlled condition that is provided with by the receiving terminal smart card is only effective to this receiving terminal, like this, whole C A condition receiving system will have toll administration pattern very flexibly, and can carry out the configuration and the adjustment of freedom and flexibility according to the requirement of concrete commercial operation and management.
Technical scheme of the present invention for convenience of description also provides its applicating example, and it is as follows that the present invention defines several notions:
Conditional information CM (Conditional Message) is the representative condition time of reception section (the reception term of validity) sent of broadcast head end and/or the condition receiving control information of time quantum (actual reception time).
Random information RM (Random Message) is the random sequence information that broadcast head end is sent.
Combination Control information CCM (Combined Control Message) is the combination of conditional information CM and random information RM, is that receiving with condition of sending of broadcast head end adds/information that descrambled control words CW is relevant.
The technical scheme that condition provided by the invention receives combination control method is the Combination Control information CCM that conditional information CM and the random information RM condition that constitutes receive to be constituted add/the input data of descrambled control words CW, and Combination Control information CCM is carried out being added behind the crypto-operation/descrambled control words CW.
For the grouping symmetric key algorithm, for example DES or 3DES algorithm, a kind of available scheme is added/descrambled control words CW after conditional information CM and random information RM are adopted the mode cryptographic calculation of CBC (Cipher Block Chaining) cryptographic block link.Like this, adding on the one hand/added conditional information in the descrambled control words CW related data, do not influencing again on the other hand and add/randomness of descrambled control words CW.Send to receiving terminal as long as broadcast head end will comprise the Combination Control information CCM of conditional information CM and random information RM, receiving terminal is given smart card with CCM and is decrypted.Smart card at first relatively or upgrade self controlled condition information according to wherein conditional information CM, and according to relatively or upgrade result's decision and whether calculate and export correct adding/descrambled control words CW.Receiving terminal all can not obtain correct adding/descrambled control words CW for any artificial modification of conditional information CM or random information RM.
A kind of controlled condition is section effective time that secrete key of smart card uses.This controlled condition can be carried out under control of authority outside the read-write operation, can also compare conditional information CM from broadcast head end automatically and whether meet controlled condition in the smart card, if conditional information CM meets the controlled condition in the smart card, then key can normally use and calculate and add/descrambled control words CW.
Another kind of controlled condition is the time quantum (can be converted into the amount of money) that secrete key of smart card uses.These controlled condition data can increase or reduce under control of authority outside the operation, can also upgrade the controlled condition in the smart card according to the conditional information CM from broadcast head end automatically.If the controlled condition after upgrading does not exceed the limit of certain setting, then key can normally use and calculate and add/descrambled control words CW.
Adapt condition acceptance control method involved in the present invention and use the smart card of this method can be used alone or in combination above two kinds of controlled conditions with different toll administration patterns.Two kinds of controlled conditions have different control purposes, wherein time period controlled condition is to use the term of validity to control to key, key can not continue to use after for example surpassing the time limit sometime, prohibitive amount not in time bar: time quantum controlled condition is that the cumulative time of the actual use of key is controlled, and for example adds up can not continue to use after actual reception time quantum (or amount of money) surpasses the time quantum of buying in advance (or amount of money); The Combination Control of dual mode can be in specific term of validity scope inter-sync control actual accumulative total amount service time (or amount of money).
Time quantum controlled condition only has reading or reduces the authority of quantity in receiving terminal this locality, time period controlled condition only has the authority of reading in receiving terminal this locality.But the minimizing of the time quantum that the key that is associated with time quantum or time period controlled condition can be finished automatically in smartcard internal in use and/or the comparison of time period.Need the smart card issuance management system could operate for the increase of time quantum controlled condition quantity or to the modification of time period controlled condition through behind the key authentication, the circle that is equivalent to bank card is deposited operation, can finish at bank network or site sales counter, also can carry out online encrypted test mode modification or renewal with addressing system by broadcast head end.
Effect of the present invention is: can make receiving terminal finish the dynamic judgement or the renewal of authorising conditional automatically when the ECM Entitlement Control Message that adds/separate control word CW information to comprising carries out the key calculation process, broadcast head end only need send the Entitlement Control Message ECM at whole receiving terminals, do not send or few Entitlement Management Message EMM that needs the addressing wheel to broadcast that sends, can guarantee that receiving terminal receives the ECM Entitlement Control Message very soon after start, can overcome the bandwidth bottleneck that increment Entitlement Management Message EMM wheel is broadcast again, increase substantially the information transfer efficiency of condition receiving system and simplify the workload of broadcast head end authentication management system.
Described smart card only need use the Entitlement Control Message ECM of broadcast head end at whole receiving terminals, just can finish the dynamic control of condition of acceptance in receiving terminal this locality automatically.Under the prerequisite of guaranteed conditions receiving system secret key safety, the CA condition receiving system does not need specific smart card is carried out the addressing Authorized operation.The circle that the smart card Authorized operation is equivalent to bank card is deposited operation, can pass through bank network or sales counter, and the payment correlative charges obtains corresponding the reception and authorizes.
Utilize condition involved in the present invention to receive combination control method, can realization condition time of reception section and two kinds of conditions receptions of time quantum control mode.So-called time period control is the condition reception control to the receiving terminal term of validity, and time quantum control is that receiving terminal time used (can be converted into other data such as the amount of money) condition is received control.More than the logical combination of two kinds of control modes can reach four kinds of control purposes: the one, both control time section, control time amount again; The 2nd, a control time section, not control time amount; The 3rd, control time section not, a control time amount; The 4th, control time section neither, control time amount not again.The service supplier can be easily at different users, different time periods, different business is selected with market strategy or adjust different control modes at any time and realize different commercial operation patterns.
Provide below in conjunction with accompanying drawing and to implement preferable related condition acceptance control method broadcast head end control information and the smart card receiving terminal application example of the present invention, concrete application mode can be on the basis of this thinking according to demand situation suitably adjust.
Description of drawings
Fig. 1 is current typical condition receiving system workflow block diagram;
Fig. 2 is for adopting condition receiving system workflow block diagram of the present invention;
Fig. 3 is the crypto-operation that the adopts of the present invention adding/descrambled control words CW flow chart of giving an example.
Embodiment
Among Fig. 1, dynamically control information produces in broadcast head end, plaintext TS such as video, audio frequency, data carry out scrambling by multiplexing and scrambling apparatus and handle the TS that forms scrambling, the dynamic control information of ciphertext that produces of ECM, EMM that the TS of scrambling and CA module are produced and SI generator is sent to receiving terminal by multiple transmission forms such as ground, wired and satellites then, the SI generator is all relevant with the program information management content with the information that the CA module produces, and Subscriber Management System is relevant with ECM, EMM that the CA module produces.The smart card of the receiving terminal that process is authorized obtains expressly dynamically control information after by demodulation multiplexer, deciphering module the dynamic control information of ciphertext being deciphered, the transmission stream TS that utilizes expressly dynamic control information to finish scrambling by descrambler carries out scramble process, recovers and expressly transmits stream TS.
Among Fig. 2, dynamically control information produces in broadcast head end, video, audio frequency, plaintext TS such as data carry out scrambling by multiplexing and scrambling apparatus and handle the TS that forms scrambling, then with the TS of scrambling and the ECM of CA module generation, ground is passed through in the dynamic control information of ciphertext that the SI generator produces, multiple transmission forms such as wired and satellite are sent to receiving terminal, and conditional information and random information obtain the scrambling control word after adopting the mode cryptographic calculation of CBC (Cipher Block Chaining) cryptographic block link among the Combination Control information ECM that the broadcasting leading portion equipment of condition receiving system sends.The SI generator is all relevant with the program information management content with the information that the CA module produces.The receiving terminal smart card that process is authorized obtains expressly dynamically control information after by demodulation multiplexer, deciphering module the dynamic control information of ciphertext being deciphered, the transmission stream TS that utilizes expressly dynamic control information to finish scrambling by descrambler carries out scramble process, recovers and expressly transmits stream TS.Be described in detail detailed process below.
Broadcast head end obtains scrambling transmission stream TS after expressly transmitting the dynamic scrambling of stream TS process scrambling control word CW.
Scrambling transmits stream TS=scrambling algorithm (scrambling control word CW expressly transmits stream TS)
Transmit in the ECM control information that stream TS sends together with scrambling and to comprise the 16 bytes Combination Control information CCM=CM ‖ RM relevant with scrambling control word CW.Combination Control information CCM process f (key Data) obtains descrambled control words CW after the cryptographic algorithm computing, and the data of Combination Control information CCM are constructed as follows:
CCM=K1CC?YY?MM?DD?K2AA?BB?X1?X2?X3?X4?X5?X6?X7?X8,
Conditional information CM=K1 CC YY MM DD K2 AA BB wherein.
K1 is the key identification relevant with the time period, and CC YY MM DD is current time (date), can not surpass the term of validity certainly for complete 00 o'clock, means that key can freely use; K2 is the key identification relevant with time quantum, and AA BB for complete 00 time quantum does not subtract, means that key can freely use for each time quantum (rate) of reducing that uses.
Random information RM=X1 X2 X3 X4 X5 X6 X7 X8 is 8 byte random numbers.
According to above definition, if the CC YY MM DD of a certain moment conditional information CM is complete 00, AA BB is not complete 00, means that then this program constantly of this channel of cable TV CA condition receiving system need pay by the actual reception time; If the CC YY MM DD of conditional information CM is the current time, AA BB is complete 00, means that then this program constantly of this channel can arbitrarily receive before the deadline; If CC YY MM DD is the current time, and AA BB is not complete 00, means that then these program needs constantly of this channel are paid by the actual reception time before the deadline.
Four kinds of control modes of two kinds of control method formations can and exist in the condition receiving system, and broadcast head end is provided with at any time as required and adjusts again.The service supplier also can allow the user to select one or more charge methods according to marketing strategy simultaneously.For example, adopt 4 byte representation dates (CCYYMMDD), if the user smart card term of validity is arranged to 00 00 00 00 to FF FF FF FF, then this user will not be subjected to the control of time period; Adopt the time quantum that presets in 5 byte representation cards, if the time quantum of user smart card is arranged to FF FF FF FFFF, then this user will not be subjected to the control of time quantum.
The enciphering/deciphering Key Tpe of a kind of special use of design in smart card operating system increases associated with relevant with time quantum controlled condition and and the time period associated with controlled function of being correlated with on the basis of key attributes such as the right to use of key and the power of amendment.Satisfying under the normal usufructuary prerequisite, whether each enciphering/deciphering computing is normally carried out need be operated accordingly to time quantum associated with or time period associated with.
If the associated with that defines in the key attribute is the time quantum associated with, quite with a kind of wallet file, then before each enciphering/deciphering computing, the wallet file is carried out reducing according to the time rate in the conditional information, if do not overflow, then send the enciphering/deciphering operation result, if overflow, then do not carry out the enciphering/deciphering computing and provide error message.
If the associated with that defines in the key attribute is the time period associated with, it can be certain record of binary file or log file, then the initial sum of setting in current time and the associated with in according to conditional information before each enciphering/deciphering computing stops the term of validity and compares, if the current time is within the term of validity, then carry out the enciphering/deciphering computing and send the enciphering/deciphering result, if the current time surpasses the term of validity, then do not carry out the enciphering/deciphering computing and provide error message.
Some time quantums or time period associated with can be associated with the special-purpose enciphering/deciphering key of a plurality of these types, be applicable to that the enciphering/deciphering that different info-channels adopts can adopt identical condition of acceptance control, but some generally speaking special-purpose enciphering/deciphering keys can only be associated with some control documents.A log file can have a plurality of term of validity records, is associated with different special-purpose enciphering/deciphering keys respectively.The wallet file can read under some control of authority/add/subtracts etc. expressly or the ciphertext operation, and log file also can be read and write under some control of authority and wait expressly or ciphertext is operated.
For example the numerical value of wallet file has been represented the regular hour amount or the amount of money, with 16 system integer representations.The initial sum termination time that term of validity record is deposited the term of validity in the binary-coded decimal mode, for example 20 02 01 01 20 02 12 31 represent the term of validity to stop since on December 31,1 day to 2002 year January in 2002.
Suppose that Combination Control information is K1CC YY MM DD K2 AA BB X1 X2 X3 X4 X5 X6 X7 X8, is divided into two 8 byte data pieces with Combination Control information:
Wherein:
CM=K1?CC?YY?MM?DD?K2?AA?BB
RM=X1?X2?X3?X4?X5?X6?X7?X8
At first relatively whether current time CC YY MM DD in the log file term of validity of K1 cipher key associated, if exceeded the term of validity, then stops follow-up calculating process and provides error message; If the current time before the deadline, then CM and two data blocks of RM are carried out obtaining intermediate cryptographic result data piece MM after twice encrypted url computing with the K1 key.Wallet to the K2 cipher key associated subtracts AA BB operation then, if overflow, then stops follow-up calculating process and provides error message; If do not overflow, then intermediate cryptographic result data piece MM is added/descrambled control words CW after with the K2 secret key encryption.Add/the crypto-operation flow process of the practicality of descrambled control words CW is referring to Fig. 3.
If do not carry out the control of section effective time, CC YY MM DD can be set as 00 00 00 00, if do not carry out the control of time quantum, AA BB can be set as 00 00; If do not carry out the computing of K1 key, K1 can be set as 00, if do not carry out the computing of K2 key, K2 can be set as 00.