WO2018157724A1 - 加密控制字的保护方法、硬件安全模块、主芯片和终端 - Google Patents

加密控制字的保护方法、硬件安全模块、主芯片和终端 Download PDF

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Publication number
WO2018157724A1
WO2018157724A1 PCT/CN2018/075999 CN2018075999W WO2018157724A1 WO 2018157724 A1 WO2018157724 A1 WO 2018157724A1 CN 2018075999 W CN2018075999 W CN 2018075999W WO 2018157724 A1 WO2018157724 A1 WO 2018157724A1
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WIPO (PCT)
Prior art keywords
security module
hardware security
control word
key
management message
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PCT/CN2018/075999
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English (en)
French (fr)
Inventor
盛志凡
解伟
张晶
田雪冰
熊彬
郑力铮
严海峰
方中华
王强
杨勍
陈鹏
靳龙辉
刘晶磊
Original Assignee
国家新闻出版广电总局广播科学研究院
北京永新视博数字电视技术有限公司
北京数码视讯科技股份有限公司
深圳市海思半导体有限公司
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Publication date
Application filed by 国家新闻出版广电总局广播科学研究院, 北京永新视博数字电视技术有限公司, 北京数码视讯科技股份有限公司, 深圳市海思半导体有限公司 filed Critical 国家新闻出版广电总局广播科学研究院
Priority to US16/489,592 priority Critical patent/US11308242B2/en
Publication of WO2018157724A1 publication Critical patent/WO2018157724A1/zh

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
    • H04N21/40—Client devices specifically adapted for the reception of or interaction with content, e.g. set-top-box [STB]; Operations thereof
    • H04N21/41—Structure of client; Structure of client peripherals
    • H04N21/418—External card to be used in combination with the client device, e.g. for conditional access
    • H04N21/4182—External card to be used in combination with the client device, e.g. for conditional access for identification purposes, e.g. storing user identification data, preferences, personal settings or data
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F21/00—Security arrangements for protecting computers, components thereof, programs or data against unauthorised activity
    • G06F21/70—Protecting specific internal or peripheral components, in which the protection of a component leads to protection of the entire computer
    • G06F21/71—Protecting specific internal or peripheral components, in which the protection of a component leads to protection of the entire computer to assure secure computing or processing of information
    • G06F21/72—Protecting specific internal or peripheral components, in which the protection of a component leads to protection of the entire computer to assure secure computing or processing of information in cryptographic circuits
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L9/00—Cryptographic mechanisms or cryptographic arrangements for secret or secure communications; Network security protocols
    • H04L9/08—Key distribution or management, e.g. generation, sharing or updating, of cryptographic keys or passwords
    • H04L9/0891—Revocation or update of secret information, e.g. encryption key update or rekeying
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F21/00—Security arrangements for protecting computers, components thereof, programs or data against unauthorised activity
    • G06F21/10—Protecting distributed programs or content, e.g. vending or licensing of copyrighted material ; Digital rights management [DRM]
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L9/00—Cryptographic mechanisms or cryptographic arrangements for secret or secure communications; Network security protocols
    • H04L9/08—Key distribution or management, e.g. generation, sharing or updating, of cryptographic keys or passwords
    • H04L9/0894—Escrow, recovery or storing of secret information, e.g. secret key escrow or cryptographic key storage
    • H04L9/0897—Escrow, recovery or storing of secret information, e.g. secret key escrow or cryptographic key storage involving additional devices, e.g. trusted platform module [TPM], smartcard or USB
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L9/00—Cryptographic mechanisms or cryptographic arrangements for secret or secure communications; Network security protocols
    • H04L9/32—Cryptographic mechanisms or cryptographic arrangements for secret or secure communications; Network security protocols including means for verifying the identity or authority of a user of the system or for message authentication, e.g. authorization, entity authentication, data integrity or data verification, non-repudiation, key authentication or verification of credentials
    • H04L9/3234—Cryptographic mechanisms or cryptographic arrangements for secret or secure communications; Network security protocols including means for verifying the identity or authority of a user of the system or for message authentication, e.g. authorization, entity authentication, data integrity or data verification, non-repudiation, key authentication or verification of credentials involving additional secure or trusted devices, e.g. TPM, smartcard, USB or software token
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
    • H04N21/20—Servers specifically adapted for the distribution of content, e.g. VOD servers; Operations thereof
    • H04N21/25—Management operations performed by the server for facilitating the content distribution or administrating data related to end-users or client devices, e.g. end-user or client device authentication, learning user preferences for recommending movies
    • H04N21/266—Channel or content management, e.g. generation and management of keys and entitlement messages in a conditional access system, merging a VOD unicast channel into a multicast channel
    • H04N21/26606—Channel or content management, e.g. generation and management of keys and entitlement messages in a conditional access system, merging a VOD unicast channel into a multicast channel for generating or managing entitlement messages, e.g. Entitlement Control Message [ECM] or Entitlement Management Message [EMM]
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
    • H04N21/20—Servers specifically adapted for the distribution of content, e.g. VOD servers; Operations thereof
    • H04N21/25—Management operations performed by the server for facilitating the content distribution or administrating data related to end-users or client devices, e.g. end-user or client device authentication, learning user preferences for recommending movies
    • H04N21/266—Channel or content management, e.g. generation and management of keys and entitlement messages in a conditional access system, merging a VOD unicast channel into a multicast channel
    • H04N21/26613—Channel or content management, e.g. generation and management of keys and entitlement messages in a conditional access system, merging a VOD unicast channel into a multicast channel for generating or managing keys in general
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
    • H04N21/40—Client devices specifically adapted for the reception of or interaction with content, e.g. set-top-box [STB]; Operations thereof
    • H04N21/41—Structure of client; Structure of client peripherals
    • H04N21/426—Internal components of the client ; Characteristics thereof
    • H04N21/42607—Internal components of the client ; Characteristics thereof for processing the incoming bitstream
    • H04N21/42623—Internal components of the client ; Characteristics thereof for processing the incoming bitstream involving specific decryption arrangements
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N21/00—Selective content distribution, e.g. interactive television or video on demand [VOD]
    • H04N21/40—Client devices specifically adapted for the reception of or interaction with content, e.g. set-top-box [STB]; Operations thereof
    • H04N21/45—Management operations performed by the client for facilitating the reception of or the interaction with the content or administrating data related to the end-user or to the client device itself, e.g. learning user preferences for recommending movies, resolving scheduling conflicts
    • H04N21/462—Content or additional data management, e.g. creating a master electronic program guide from data received from the Internet and a Head-end, controlling the complexity of a video stream by scaling the resolution or bit-rate based on the client capabilities
    • H04N21/4623—Processing of entitlement messages, e.g. ECM [Entitlement Control Message] or EMM [Entitlement Management Message]

Definitions

  • the control word is decrypted to obtain a control word, and the control word is re-encrypted according to the re-encryption key stored in the hardware security module to obtain a re-encrypted control word;
  • a secure storage area configured to store a hardware security module root key, a re-encryption key, and the hardware security module authorization management message
  • a first decryption engine configured to decrypt the encrypted control word according to the hardware security module authorization management message and the hardware security module root key to obtain a control word
  • a first sending unit configured to send the re-encrypted control word to the main chip, so that the main chip decrypts the re-encrypted control word according to the main chip authorization management message sent by the front end to obtain a control word, where the main The chip authorization management message includes a key set to decrypt the re-encrypted control word.
  • a master chip for use in a downloadable conditional access system including:
  • a second sending unit configured to send the hardware security module authorization management message and the encryption control word to the hardware security module, so that the hardware security module authorizes the management message according to the hardware security module and the hardware security module root stored in the hardware security module Decrypting the encrypted control word to obtain a control word, and re-encrypting the control word according to a re-encryption key stored in the hardware security module to obtain a re-encrypted control word;
  • a fourth receiving unit configured to receive the re-encrypted control word sent by the hardware security module
  • a second decryption engine configured to decrypt the re-encrypted control word according to the master chip-derived master chip root key and the master chip grant management message to obtain a control word to descramble the scrambled content according to the control word.
  • a terminal applied to a downloadable condition receiving system includes: a hardware security module as described above and a main chip as described above.
  • Embodiment 1 is a flowchart of a method for protecting an encrypted control word according to Embodiment 1;
  • Embodiment 3 is a flowchart of a method for protecting an encrypted control word provided in Embodiment 3;
  • FIG. 6 is a schematic structural diagram of a hardware security module provided in Embodiment 6;
  • Embodiment 7 is a schematic structural diagram of a main chip provided in Embodiment 7;
  • Embodiment 1 is a flowchart of a method for protecting an encrypted control word according to Embodiment 1.
  • the present embodiment is applicable to a downloadable condition receiving system DCAS, wherein the DCAS includes a front end and a terminal, and the terminal includes a main chip and a hardware security module, and the method includes This can be performed by the hardware security module.
  • a hardware security module (HSM) is a dedicated encryption processor designed to protect the encryption key life cycle.
  • the hardware security module is securely managed, processed, and processed in a reliable and tamper-proof device. Save encryption keys to secure the encryption keys used in transactions, applications, and sensitive data.
  • the method of this embodiment includes steps 110-140:
  • step 110 the hardware security module authorization management message and the encryption control word sent by the main chip are received, wherein the hardware security module authorization management message includes a key for decrypting the encrypted control word.
  • control word is used by the front end to scramble the audio and video content subscribed by the user, for example, the content of the digital television, and the control word can be used to descramble the scrambled content to view the audio and video content. Therefore, the control word needs to be encrypted and only authorized users can decrypt it, thus ensuring the normal operation of the system.
  • the hardware security module authorization management message includes a key for decrypting the encrypted control word.
  • step 120 the encrypted control word is decrypted according to the hardware security module authorization management message and the hardware security module root key stored in the hardware security module to obtain a control word.
  • the hardware security module root key is a root key corresponding to the hardware security module, that is, different hardware security modules have different root keys, and the root key is stored in the hardware security module and is not acquired by the outside world.
  • the encrypted control word cannot be decrypted without knowing the root key.
  • the secondary key and the tertiary key are sent to the hardware security module by the hardware chip in the manner of the hardware security module authorization management message, and the hardware security module according to the stored hardware security module root key and the hardware security module authorization management message
  • the level key and the third level key perform hierarchical decryption on the encrypted control word to obtain the plaintext of the control word.
  • the hardware security module decrypts K2 by using the stored root key Root Key and Ekroot (K2) in the encrypted control word, and then decrypts K1 by using K2 and EK2 (K1), and then uses K1 and EK1 (CW). ) Decrypt to get the control word plaintext.
  • the decryption algorithm can be set according to actual needs, such as the Advanced Encryption Standard (AES) or the 3DES algorithm (collectively referred to as a Triple Data Encryption Algorithm (TDEA) block cipher).
  • AES Advanced Encryption Standard
  • TDEA Triple Data Encryption Algorithm
  • control word plaintext needs to be re-encrypted before being fed back to the main chip.
  • the re-encryption key is CREEK, and encrypted to get Ecreek (CW).
  • step 140 the re-encrypted control word is sent to the main chip, so that the main chip decrypts the re-encrypted control word according to the main chip authorization management message sent by the front-end to obtain a control word, where the main chip authorization management message is included
  • the key of the re-encrypted control word is decrypted.
  • the service requirement for the CA is cardless one-way DCAS, so the security of the DCAS cannot be ensured by moving the data storage and authorization logic to the front end through the two-way network.
  • the implementation of the authorization logic through the hardware security module is more suitable for this cardless one-way DCAS, which enhances the security of the cardless one-way DCAS.
  • the activation described here is usually performed before the terminal is used, and it can be used normally after activation.
  • the activation request message is sent to the front end by the main chip in the terminal, and then the front end sends the activation message to the main chip, and then the main chip sends the information to the hardware security module.
  • the activation message includes at least a pairing key, a re-encryption key, and a hardware security module root key.
  • step 220 the re-encryption key and the hardware security module root key are stored, and a secure authentication channel with the main chip is established according to the pairing key.
  • the decryption operation as described in the above embodiment can be performed.
  • the secure storage area in the hardware security module may be utilized to store the re-encryption key and the hardware security module root key.
  • the pairing key is used to establish a secure authentication channel with the master chip.
  • the data transmission between the hardware security module and the master chip is based on the secure authentication channel, thereby enhancing data security.
  • step 250 the control word is re-encrypted according to the re-encryption key stored in the hardware security module to obtain a re-encrypted control word.
  • step 260 the re-encryption control word is sent to the main chip through the secure authentication channel, so that the main chip decrypts the re-encrypted control word according to the main chip authorization management message sent by the front-end to obtain a control word, where the main chip authorizes the management message.
  • a key for decrypting the re-encrypted control word is included.
  • the re-encryption key and the hardware security module root key are received and stored by the activation message, and a secure authentication channel is established with the master chip according to the pairing key in the activation message, thereby enhancing data security.
  • Embodiment 3 is a flowchart of a method for protecting an encrypted control word according to Embodiment 3.
  • the present embodiment is applicable to a downloadable condition receiving system DCAS, wherein the DCAS includes a front end and a terminal, and the terminal includes a main chip and a hardware security module, and the method includes It can be executed by the main chip.
  • the method of the third embodiment includes steps 310-330:
  • the control word is used for scrambling the audio and video content to be played by the front end.
  • the terminal is authorized, and the main chip is sent to the main chip by the main chip authorization management message and the hardware security module authorization management message.
  • the hardware security module authorization management message is sent to the hardware security module, so that the hardware security module decrypts the encrypted control word, and the main chip can also decrypt the control word re-encrypted by the hardware security module by using the main chip authorization management message.
  • the front end can transmit the above content to each terminal through a broadcast channel, for example, and the terminal receives it according to its own needs.
  • step 320 the hardware security module authorization management message and the encryption control word are sent to the hardware security module, so that the hardware security module controls the encryption according to the hardware security module authorization management message and the hardware security module root key stored in the hardware security module.
  • the word is decrypted to obtain a control word, and the control word is re-encrypted according to the re-encryption key stored in the hardware security module to obtain a re-encrypted control word.
  • step 330 the re-encrypted control word sent by the hardware security module is received, and the re-encrypted control word is decrypted according to the main chip root key derived from the main chip and the main chip authorization management message, to obtain a control word, so as to descramble the scrambled content according to the control word.
  • the master chip root key corresponds to the master chip.
  • the master chip root key is derived by using a derivative algorithm built in the master chip.
  • the master chip security key may be stored in a One Time Programmable (OTP) area inside the main chip; the derived identifier is related to the selected CA, and may be configured in the software running in the terminal, when there is When decrypting the demand, the software sends the command to the main chip. If the CA is changed, the derivative identifier can be changed by updating the software. Therefore, different master chips can derive different master chip root keys according to different CAs to meet the needs of flexibility.
  • OTP One Time Programmable
  • the primary chip three-level key may be the same as the re-encryption key, and the front end encrypts the control word CW with the primary chip secondary key K2' to the third-level key K1' to obtain EK2 (K1), and then uses the primary
  • the chip root key K3 encrypts the secondary key K2' to obtain EK3 (K2), EK3 (K2) and EK2 (K1) are sent to the main chip as an encrypted control word, and the main chip decrypts K2 by K3 and EK3 (K2).
  • K1' is decrypted by using EK2 (K1) and K2', and the control word and the K1' decrypted by the hardware security module are sent to obtain the control word plaintext, and the scrambled content is finally descrambled for playing.
  • the authorization control is completed by the main chip and the hardware security module, thereby enhancing the security of the DCAS by using the hardware security module. And especially suitable for cardless one-way DCAS.
  • Embodiment 4 is a flowchart of a method for protecting an encrypted control word provided in Embodiment 4.
  • the fourth embodiment is further optimized based on the foregoing embodiment. As shown in FIG. 4, the method of Embodiment 4 includes steps 410-460:
  • step 410 an activation request message is generated, and the activation request message is sent to the front end, wherein the activation request message includes at least a main chip identifier, a conditional access certificate, and a chip certificate of the hardware security module.
  • step 420 the activation message sent by the front end is received, and the activation message is sent to the hardware security module, where the activation message includes at least a pairing key, a re-encryption key, and a hardware security module root key, and the activation message
  • the activation message includes at least a pairing key, a re-encryption key, and a hardware security module root key, and the activation message
  • the pairing key, the re-encryption key, and the hardware security module root key are distributed by the front end according to the activation request message.
  • step 430 a secure authentication channel with the hardware security module is established based on the pairing key.
  • step 440 the encrypted control word, the scrambled content, the primary chip grant management message, and the hardware security module authorization management message sent by the front end are received.
  • step 450 the hardware security module authorization management message and the encryption control word are sent to the hardware security module through the secure authentication channel, so that the hardware security module authorizes the management message according to the hardware security module and the hardware security module root stored in the hardware security module.
  • the key decrypts the encrypted control word to obtain a control word, and re-encrypts the control word according to the re-encryption key stored in the hardware security module to obtain a re-encrypted control word.
  • FIG. 5 is a flowchart of protection of an encrypted control word in the method provided in Embodiment 5.
  • the fifth embodiment is further described on the basis of the foregoing embodiment. As shown in FIG. 5, the method of Embodiment 5 includes:
  • the main chip generates an activation request message, and sends an activation request message to the front end, wherein the activation request message includes at least a main chip identifier, a conditional access certificate, and a chip certificate of the hardware security module.
  • the master chip sends the pairing key, the re-encryption key, and the hardware security module root key in the activation message to the hardware security module.
  • the hardware security module stores the re-encryption key and the hardware security module root key, and establishes a secure authentication channel with the main chip by using the pairing key.
  • the front end sends an encrypted control word, scrambled content, a main chip authorization management message, and a hardware security module authorization management message to the main chip.
  • the hardware security module decrypts the encrypted control word according to the hardware security module authorization management message and the hardware security module root key stored in the hardware security module, obtains the control word, and controls according to the re-encryption key pair stored in the hardware security module.
  • the word is re-encrypted to obtain a re-encrypted control word.
  • the hardware security module sends the re-encrypted control word to the main chip through the secure authentication channel through the secure authentication channel.
  • the main chip decrypts the re-encrypted control word according to the main chip root key derived from the main chip and the main chip authorization management message, and obtains a control word to descramble the scrambled content according to the control word.
  • This embodiment is applicable to DCAS, and is especially suitable for cardless one-way DCAS, which enhances the security of cardless one-way DCAS.
  • FIG. 6 is a schematic structural diagram of a hardware security module provided in Embodiment 6.
  • the hardware security module is applied to DCAS.
  • the DCAS includes a front end and a terminal, and the terminal includes a main chip and the hardware security module.
  • the hardware security module 6 includes:
  • the secure storage area 61 is configured to store a hardware security module root key, a re-encryption key, and the hardware security module authorization management message.
  • the first decryption engine 62 is configured to decrypt the encrypted control word according to the hardware security module authorization management message and the hardware security module root key to obtain a control word.
  • a first sending unit 64 configured to send the re-encrypted control word to the main chip, so that the main chip decrypts the re-encrypted control word according to the main chip authorization management message sent by the front end to obtain a control word, where
  • the master chip authorization management message includes a key for decrypting the re-encrypted control word.
  • the hardware security module 6 further includes:
  • a second receiving unit configured to receive an activation message sent by the primary chip, where the activation message includes at least a pairing key, the re-encryption key, and a hardware security module root key;
  • the first pairing unit (not shown) is configured to establish a secure authentication channel with the master chip according to the pairing key.
  • the first receiving unit 60 is configured to: receive the hardware security module authorization management message and the encryption control word sent by the main chip, and include: receiving, by the security authentication channel, the hardware security module authorization management message and the encryption control sent by the main chip word;
  • the first sending unit 64 is configured to: send the re-encrypted control word to the main chip by using the secure authentication channel.
  • the hardware security module authorization management message includes a hardware security module secondary key and a hardware security module third-level key
  • the first decryption engine 62 is configured to:
  • the hardware security module 6 further includes:
  • An update unit (not shown) is configured to receive a key refresh command sent by the master chip, and update and store the hardware security module authorization management message, the hardware security module root key, and the re-encryption key.
  • the secure storage area 61 is further configured to store the updated hardware security module authorization management message, the hardware security module root key, and the re-encryption key.
  • the main chip 7 is a schematic structural diagram of a main chip provided in Embodiment 7, the main chip is applied to DCAS, and the DCAS includes a front end and a terminal, and the terminal includes a main chip and the hardware security module. As shown in FIG. 7, the main chip 7 includes:
  • a second sending unit 72 configured to send the hardware security module authorization management message and the encryption control word to the hardware security module, so that the hardware security module authorizes the management message according to the hardware security module and the hardware security module stored in the hardware security module a root key, decrypting the encrypted control word, obtaining a control word, and re-encrypting the control word according to a re-encryption key stored in the hardware security module to obtain a re-encrypted control word;
  • a second decryption engine 74 configured to decrypt the re-encrypted control word according to a master chip root key derived from a master chip and the master chip grant management message, to obtain a control word, to descramble the scrambled content according to the control word .
  • the main chip 7 further includes:
  • An activation request message generating unit (not shown) is configured to generate an activation request message, and send the activation request message to the front end, where the activation request message includes at least a main chip identifier, a conditional receiving certificate, and hardware security.
  • Module certificate of the module is configured to generate an activation request message, and send the activation request message to the front end, where the activation request message includes at least a main chip identifier, a conditional receiving certificate, and hardware security.
  • a second pairing unit (not shown) is configured to establish a secure authentication channel with the hardware security module according to the pairing key.
  • the fourth receiving unit 73 is configured to: receive, by using the secure authentication channel, the re-encrypted control word sent by the hardware security module.
  • the main chip 7 further includes:
  • the root key derivation unit (not shown) is configured to derive the main chip root key by using a main chip built-in derivation algorithm according to the main chip security key and the derivation identifier.
  • the primary chip authorization management message includes a primary chip secondary key and a primary chip tertiary key; correspondingly, the second decryption engine 74 is configured to:
  • the authorization control is completed by the main chip and the hardware security module, thereby enhancing the security of the DCAS by using the hardware security module. And especially suitable for cardless one-way DCAS.
  • the hardware security module includes: a processor 910 and a memory 920; and may further include a communication interface 930 and a bus 940.
  • the memory 920 can include a storage program area and a storage data area, and the storage program area can store an operating system and an application required for at least one function.
  • the storage data area can store data and the like created according to the use of the electronic device.
  • the memory may include, for example, a volatile memory of a random access memory, and may also include a non-volatile memory. For example, flash memory devices or other non-transitory solid state memory devices.
  • the embodiment further provides a computer readable storage medium storing computer executable instructions, the computer executable instructions being set to the method of any of the above.
  • the method for protecting the encrypted control word of the present disclosure can ensure the security of the DCAS and enable the terminal to decrypt the control word and descramble the audio and video stream more securely.

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Abstract

一种加密控制字的保护方法，包括：接收主芯片发送的硬件安全模块授权管理消息和加密控制字，其中，硬件安全模块授权管理消息中包括用于解密加密控制字的密钥；根据硬件安全模块授权管理消息和硬件安全模块中存储的硬件安全模块根密钥，对加密控制字进行解密，得到控制字；根据硬件安全模块中存储的重加密密钥对控制字进行重加密，得到重加密控制字；将重加密控制字发送到主芯片，以便主芯片根据前端发送的主芯片授权管理消息解密重加密控制字，得到控制字。

Description

加密控制字的保护方法、硬件安全模块、主芯片和终端 技术领域
本公开涉及消息安全技术，例如涉及一种加密控制字的保护方法、硬件安全模块、主芯片和终端。
背景技术
条件接收系统(Conditional Access System，CAS)是数字电视加密控制的核心技术保证，为数字电视的运营提供了必要的技术手段，使拥有授权的用户合法的使用特定的一项业务，而未经授权的用户不能使用这一业务。基于条件接收系统，CAS与机顶盒绑定在一起，制约了行业的发展。为解决此问题，基于软硬件分离的可下载条件接收系统(Downloadable Conditional Access System，DCAS)应运而生。
DCAS是一套完整的端到端业务保护系统，由前端、终端和安全数据管理平台组成。其中，前端对输入的音视频流进行加扰，通过广播信道或双向通信向终端发送加密控制字等条件接收的授权等消息，其中，控制字(Control Word，CW)用于对音视频流进行解扰，从而完成业务的加密保护传送和合法授权控制管理。
通常，在传统的CAS中，智能卡是条件存取操作(Conditional Access，CA)在机顶盒端的硬件安全核心，用来存储授权密钥并参与控制字的生成。智能卡内部的数据存储和逻辑判断被视为可信消息，向机顶盒的其它组件提供解扰控制字。而与有卡CAS相比，DCAS没有智能卡这样的可信执行环境和安全存储，因此如何保证DCAS的安全性，并使终端能够安全地从前端获取授权并解扰音视频流，成为亟待解决的问题。
发明内容
本公开提供一种加密控制字的保护方法、硬件安全模块、主芯片和终端，以保证DCAS的安全性，并使终端能够安全地从前端获取授权并解扰音视频流。
一种加密控制字的保护方法，包括：
接收主芯片发送的硬件安全模块授权管理消息和加密控制字，其中，所述硬件安全模块授权管理消息中包括用于解密所述加密控制字的密钥；
根据所述硬件安全模块授权管理消息和硬件安全模块中存储的硬件安全模块根密钥，对所述加密控制字进行解密，得到控制字；
根据硬件安全模块中存储的重加密密钥对所述控制字进行重加密，得到重加密控制字；以及
将所述重加密控制字发送到主芯片，以便主芯片根据所述前端发送的主芯片授权管理消息解密所述重加密控制字，得到控制字，其中，所述主芯片授权管理消息中包括用于解密所述重加密控制字的密钥。
一种加密控制字的保护方法，包括：
接收前端发送的加密控制字、加扰内容、主芯片授权管理消息和硬件安全模块授权管理消息；
将所述硬件安全模块授权管理消息和加密控制字发送至硬件安全模块，以便硬件安全模块根据所述硬件安全模块授权管理消息和硬件安全模块中存储的硬件安全模块根密钥，对所述加密控制字进行解密，得到控制字，并根据硬件安全模块中存储的重加密密钥对所述控制字进行重加密，得到重加密控制字；以及
接收硬件安全模块发送的所述重加密控制字，根据主芯片派生的主芯片根密钥和所述主芯片授权管理消息解密所述重加密控制字，得到控制字，以便根据所述控制字解扰所述加扰内容。
一种硬件安全模块，配置于可下载条件接收系统，包括：
第一接收单元，设置为接收主芯片发送的硬件安全模块授权管理消息和加密控制字，其中，所述硬件安全模块授权管理消息中包括设置为解密所述加密控制字的密钥；
安全存储区域，设置为存储硬件安全模块根密钥、重加密密钥和所述硬件安全模块授权管理消息；
第一解密引擎，设置为根据所述硬件安全模块授权管理消息和硬件安全模块根密钥，对所述加密控制字进行解密，得到控制字；
重加密引擎，设置为根据所述重加密密钥对所述控制字进行重加密，得到重加密控制字；
第一发送单元，设置为将所述重加密控制字发送到主芯片，以便主芯片根据所述前端发送的主芯片授权管理消息解密所述重加密控制字，得到控制字， 其中，所述主芯片授权管理消息中包括设置为解密所述重加密控制字的密钥。
一种主芯片，应用于可下载条件接收系统，包括：
第三接收单元，设置为接收前端发送的加密控制字、加扰内容、主芯片授权管理消息和硬件安全模块授权管理消息；
第二发送单元，设置为将所述硬件安全模块授权管理消息和加密控制字发送至硬件安全模块，以便硬件安全模块根据所述硬件安全模块授权管理消息和硬件安全模块中存储的硬件安全模块根密钥，对所述加密控制字进行解密，得到控制字，并根据硬件安全模块中存储的重加密密钥对所述控制字进行重加密，得到重加密控制字；
第四接收单元，设置为接收硬件安全模块发送的所述重加密控制字；
第二解密引擎，设置为根据主芯片派生的主芯片根密钥和所述主芯片授权管理消息解密所述重加密控制字，得到控制字，以便根据所述控制字解扰所述加扰内容。
一种终端，应用于可下载条件接收系统，包括：如上所述的硬件安全模块和如上所述的主芯片。
一种计算机可读存储介质，存储有计算机可执行指令，所述计算机可执行指令设置为上述任一项的方法。
本公开的加密控制字的保护方法，使得外界无法从硬件安全模块中截取到解密的重要信息，从而利用该硬件安全模块增强了DCAS的安全性。
附图说明
图1是实施例一提供的加密控制字的保护方法的流程图；
图2是实施例二提供的加密控制字的保护方法的流程图；
图3是实施例三提供的加密控制字的保护方法的流程图；
图4是实施例四提供的加密控制字的保护方法的流程图；
图5是实施例五提供的加密控制字的保护方法的流程图；
图6是实施例六提供的硬件安全模块的结构示意图；
图7是实施例七提供的主芯片的结构示意图；
图8是实施例八提供的终端的结构示意图；
图9是实施例九提供的硬件安全模块结构示意图。
具体实施方式
实施例一
图1为实施例一提供的加密控制字的保护方法的流程图，本实施例可应用于可下载条件接收系统DCAS，其中，DCAS包括前端和终端，终端包括主芯片和硬件安全模块，该方法可以由该硬件安全模块来执行。本实施例中硬件安全模块(Hardware Security Module，HSM、)是专为保护加密密钥生命周期而设计的专用加密处理器，硬件安全模块通过在可靠且防篡改的设备中安全地管理、处理和保存加密密钥，保护交易、应用程序和敏感数据中使用的加密密钥的安全。本实施例的方法包括步骤110-140：
在步骤110中，接收主芯片发送的硬件安全模块授权管理消息和加密控制字，其中，所述硬件安全模块授权管理消息中包括用于解密所述加密控制字的密钥。
本实施例中，控制字用于前端对用户订阅的音视频内容进行加扰，例如数字电视的内容，知道控制字就可以对经加扰的内容解扰，从而观看音视频内容。因此，需要对控制字进行加密，并且只允许经授权的用户才能解密，从而保障系统的正常运行。硬件安全模块授权管理消息中包括用于解密加密控制字的密钥。
在步骤120中，根据硬件安全模块授权管理消息和硬件安全模块中存储的硬件安全模块根密钥，对加密控制字进行解密，得到控制字。
硬件安全模块根密钥是与该硬件安全模块一一对应的根密钥，即不同的硬件安全模块具有不同的根密钥，根密钥存储在硬件安全模块中，不会被外界获取，而不知道根密钥则无法对加密控制字进行解密。
在一实施例中，所述硬件安全模块授权管理消息包括硬件安全模块二级密钥和硬件安全模块三级密钥；相应的，根据硬件安全模块授权管理消息和硬件安全模块中存储的硬件安全模块根密钥，对所述加密控制字进行解密，得到控制字，包括：根据硬件安全模块中存储的硬件安全模块根密钥、硬件安全模块二级密钥和硬件安全模块三级密钥对加密控制字进行层级解密，得到控制字。
在一实施例中，出于安全性的考虑，DCAS采用层级密钥的机制，即前端对控制字利用三级密钥加密后，再利用二级密钥对三级密钥进行加密，再利用根 密钥对二级密钥进行加密。例如，前端对CW利用三级密钥K1加密，得到EK1(CW)，再利用二级密钥K2对K1加密，得到EK2(K1)，再利用硬件安全模块根密钥Root Key对二级密钥K2加密，得到Ekroot(K2)。其中的EK1(CW)、EK2(K1)和Ekroot(K2)共同构成所述加密控制字。其中，二级密钥和三级密钥可以是前端生成的随机数。
二级密钥和三级密钥以硬件安全模块授权管理消息的方式通过主芯片发送至硬件安全模块，硬件安全模块根据存储的硬件安全模块根密钥、该硬件安全模块授权管理消息中的二级密钥和三级密钥对加密控制字进行层级解密，获得控制字明文。在上述实施例中，硬件安全模块利用存储的根密钥Root Key和加密控制字中的Ekroot(K2)解密得到K2，再利用K2和EK2(K1)解密得到K1，再利用K1和EK1(CW)解密得到控制字明文。解密算法可以根据实际需要设置，例如对称分组密码算法(Advanced Encryption Standard，AES)或3DES算法(三重数据加密算法(Triple Data Encryption Algorithm，TDEA)块密码的统称)等。
在步骤130中，根据硬件安全模块中存储的重加密密钥对所述控制字进行重加密，得到重加密控制字。
出于安全性的考虑，控制字明文需要进行重加密后再反馈给主芯片。例如，重加密密钥为CREEK，加密后得到Ecreek(CW)。
在步骤140中，将重加密控制字发送到主芯片，以便主芯片根据前端发送的主芯片授权管理消息解密重加密控制字，得到控制字，其中，所述主芯片授权管理消息中包括用于解密所述重加密控制字的密钥。
可选地，主芯片解密重加密控制字也需要相应的密钥才能实现，该密钥是以主芯片授权管理消息的方式由前端发送给主芯片，实现对主芯片的授权，得到控制字，从而解扰加扰内容进行播放。
在一实施例中，上述硬件安全模块授权管理消息、硬件安全模块根密钥和重加密密钥可以进行更新，以满足安全性需要。更新的频率可以根据实际使用场景的需要进行设置。实现时，可以由前端通过主芯片发来密钥刷新指令，硬件安全模块根据该密钥刷新指令对原有相关密钥进行更新，并存储更新后的密钥。
本实施例通过硬件安全模块根据存储的硬件安全模块根密钥和接收到的硬 件安全模块授权管理消息对加密控制字进行解密，得到控制字，再根据硬件安全模块中存储的重加密密钥对所述控制字进行重加密，得到重加密控制字，之后将所述重加密控制字发送到主芯片，以便主芯片根据前端发送的主芯片授权管理消息解密所述重加密控制字，得到控制字，由于外界无法从硬件安全模块中截取到解密的重要信息，从而利用该硬件安全模块增强了DCAS的安全性。
此外，对于如卫星直播广播电视系统而言，其对CA的业务需求是无卡单向DCAS，那么无法通过双向网络通过将数据存储和授权逻辑移至前端来保证DCAS的安全性，而本实施例通过硬件安全模块实现授权逻辑，更加适用于这种无卡单向DCAS，增强了了无卡单向DCAS的安全性。
实施例二
图2为实施例二提供的方法的流程图，实施例二在实施例一的基础上，对终端激活的操作进行改变。如图2所示，本实施例二的方法包括步骤210-260：
在步骤210中，接收主芯片发送的激活消息，所述激活消息中至少包括配对密钥、所述重加密密钥和硬件安全模块根密钥。
此处所述的激活，通常是在终端使用之前进行，激活后就可以正常使用了。本实施例中，是由终端中的主芯片向前端发送激活请求消息，然后前端将激活消息发送至主芯片，再由主芯片发送给硬件安全模块。激活消息中至少包括配对密钥、重加密密钥和硬件安全模块根密钥。
此外，激活也可以由人工协助完成，例如，技术人员通过扫描终端上的二维码获取终端的信息，并通过客户端软件上传至前端实现激活请求消息的发送，然后在通过客户端软件接收激活消息并人工传到终端的主芯片。
在步骤220中，存储重加密密钥和硬件安全模块根密钥，并根据配对密钥建立与主芯片的安全认证通道。
保存重加密密钥和硬件安全模块根密钥后，就可以进行如上述实施例所述的解密操作了。本实施例中，可以利用硬件安全模块中的安全存储区域来存储重加密密钥和硬件安全模块根密钥。
此外，还需要在激活后利用配对密钥建立与主芯片的安全认证通道，在使用过程中，硬件安全模块与主芯片之间数据传送都是基于该安全认证通道，从而增强数据的安全性。
在步骤230中，通过安全认证通道接收主芯片发送的硬件安全模块授权管 理消息和加密控制字。
在步骤240中，根据硬件安全模块中存储的硬件安全模块根密钥、硬件安全模块二级密钥和硬件安全模块三级密钥对加密控制字进行层级解密，得到控制字。
在步骤250中，根据硬件安全模块中存储的重加密密钥对控制字进行重加密，得到重加密控制字。
在步骤260中，通过所述安全认证通道将重加密控制字发送到主芯片，以便主芯片根据前端发送的主芯片授权管理消息解密重加密控制字，得到控制字，其中，主芯片授权管理消息中包括用于解密重加密控制字的密钥。
本实施例通过激活消息接收并存储重加密密钥和硬件安全模块根密钥，并根据激活消息中的配对密钥与主芯片建立安全认证通道，从而增强数据的安全性。
实施例三
图3是实施例三提供的加密控制字的保护方法的流程图，本实施例可应用于可下载条件接收系统DCAS，其中，DCAS包括前端和终端，终端包括主芯片和硬件安全模块，该方法可以由主芯片来执行。实施例三的方法包括步骤310-330：
在步骤310中，接收前端发送的加密控制字、加扰内容、主芯片授权管理消息和硬件安全模块授权管理消息。
其中，控制字是用于前端对待播放的音视频内容进行加扰的，控制字加密后对终端进行授权，以主芯片授权管理消息和硬件安全模块授权管理消息的方式发送给主芯片，主芯片将硬件安全模块授权管理消息发送给硬件安全模块，以便硬件安全模块对加密控制字进行解密，主芯片也可以利用主芯片授权管理消息对硬件安全模块重加密后的控制字进行解密。
这里，前端例如可以通过广播信道将上述内容发送给各终端，终端根据自己的需要接收。
在步骤320中，将硬件安全模块授权管理消息和加密控制字发送至硬件安全模块，以便硬件安全模块根据硬件安全模块授权管理消息和硬件安全模块中存储的硬件安全模块根密钥，对加密控制字进行解密，得到控制字，并根据硬件安全模块中存储的重加密密钥对控制字进行重加密，得到重加密控制字。
其中，关于硬件安全模块的上述操作，已经在实施例一和实施例二中阐述，这里不再赘述。
在步骤330中，接收硬件安全模块发送的重加密控制字，根据主芯片派生的主芯片根密钥和主芯片授权管理消息解密重加密控制字，得到控制字，以便根据控制字解扰加扰内容。
可选的，主芯片根密钥与主芯片相对应，本实施例中是根据主芯片安全密钥和派生标识，并利用主芯片内置的派生算法，派生出主芯片根密钥。其中，主芯片安全密钥可以存储在主芯片内部的一次性写入后不可更改的(One Time Programmable，OTP)区域；派生标识与所选CA有关，可以配置在终端运行的软件中，当有解密需求时，由该软件通过指令的方式下发给主芯片，若更改CA，可以通过更新该软件的方式来更改派生标识。因此，不同的主芯片根据不同的CA可以派生出不同的主芯片根密钥，以满足灵活性的需要。
在一实施例中，可以采用层级密钥机制。所述主芯片授权管理消息包括主芯片二级密钥和主芯片三级密钥；相应的，所述根据主芯片派生的主芯片根密钥和所述主芯片授权管理消息解密所述重加密控制字，得到控制字，包括：根据所述主芯片根密钥、主芯片二级密钥和主芯片三级密钥对所述重加密控制字进行层级解密，得到控制字，其中，所述主芯片三级密钥与所述重加密密钥相对应。例如，可以是主芯片三级密钥与重加密密钥相同，那么前端将控制字CW用主芯片二级密钥K2’对三级密钥K1’加密，得到EK2(K1)，再用主芯片根密钥K3对二级密钥K2’加密得到EK3(K2)，EK3(K2)和EK2(K1)作为加密控制字发送给主芯片，主芯片利用K3和EK3(K2)解密得到K2’，利用EK2(K1)和K2’解密得到K1’，利用硬件安全模块发送给主芯片经重加密后的控制字和K1’解密得到控制字明文，最终解扰加扰内容进行播放。
本实施例通过主芯片与硬件安全模块完成授权控制，从而利用该硬件安全模块增强了DCAS的安全性。并且尤其适用于无卡单向DCAS。
实施例四
图4是实施例四提供的加密控制字的保护方法的流程图，实施例四在上述实施例的基础上进行进一步优化。如图4所示，实施例四的方法包括步骤410-460：
在步骤410中，生成激活请求消息，将所述激活请求消息发送至前端，其中，激活请求消息中至少包括主芯片标识、条件接收证书和硬件安全模块的芯 片证书。
在步骤420中，接收前端发送的激活消息，并将激活消息发送至硬件安全模块，其中，激活消息中至少包括配对密钥、重加密密钥和硬件安全模块根密钥，并且激活消息中的配对密钥、重加密密钥和硬件安全模块根密钥为前端根据所述激活请求消息派发。
本实施例中，激活请求消息中携带的信息是作为前端派发配对密钥、重加密密钥和硬件安全模块根密钥的依据。前端在校验激活请求消息的合法性之后，根据主芯片标识、条件接收证书和硬件安全模块的芯片证书等信息，为终端中的硬件安全模块派发相对应的重加密密钥和硬件安全模块根密钥，并为终端中的主芯片和硬件安全模块建立他们之间的安全认证通道派发相对应的配对密钥。
在步骤430中，根据配对密钥建立与硬件安全模块的安全认证通道。
在步骤440中，接收前端发送的加密控制字、加扰内容、主芯片授权管理消息和硬件安全模块授权管理消息。
在步骤450中，通过安全认证通道将硬件安全模块授权管理消息和加密控制字发送至硬件安全模块，以便硬件安全模块根据所述硬件安全模块授权管理消息和硬件安全模块中存储的硬件安全模块根密钥，对所述加密控制字进行解密，得到控制字，并根据硬件安全模块中存储的重加密密钥对所述控制字进行重加密，得到重加密控制字。
在步骤460中，通过安全认证通道接收硬件安全模块发送的所述重加密控制字，根据主芯片派生的主芯片根密钥和所述主芯片授权管理消息解密所述重加密控制字，得到控制字，以便根据所述控制字解扰所述加扰内容。
本实施例通过激活操作获取配对密钥、重加密密钥和硬件安全模块根密钥，利用配对密钥建立与硬件安全模块之间的安全认证通道，并在激活操作之后，根据前端发送的主芯片安全密钥和派生标识派生出主芯片根密钥，用于后续的控制字解密操作，增强了DCAS的安全性。
实施例五
图5是实施例五提供的方法的加密控制字的保护流程图，实施例五在上述实施例的基础上进行进一步说明。如图5所示，实施例五的方法包括：
①主芯片生成激活请求消息，将激活请求消息发送至前端，其中，所述激活请求消息中至少包括主芯片标识、条件接收证书和硬件安全模块的芯片证书。
②前端根据所述激活请求消息生成激活消息，并将该激活消息发送至主芯片，其中，所述激活消息中至少包括配对密钥、所述重加密密钥和硬件安全模块根密钥。
③主芯片将所述激活消息中的配对密钥、重加密密钥和硬件安全模块根密钥发送给硬件安全模块。
④硬件安全模块存储所述重加密密钥和硬件安全模块根密钥，并利用配对密钥与主芯片建立安全认证通道。
⑤前端向主芯片发送加密控制字、加扰内容、主芯片授权管理消息和硬件安全模块授权管理消息。
⑥主芯片通过安全认证通道将硬件安全模块授权管理消息和加密控制字发送至硬件安全模块。
⑦硬件安全模块根据硬件安全模块授权管理消息和硬件安全模块中存储的硬件安全模块根密钥，对加密控制字进行解密，得到控制字，并根据硬件安全模块中存储的重加密密钥对控制字进行重加密，得到重加密控制字。
⑧硬件安全模块通过安全认证通道将重加密后的控制字通过安全认证通道发送给主芯片。
⑨主芯片根据主芯片派生的主芯片根密钥和主芯片授权管理消息解密重加密控制字，得到控制字，以便根据控制字解扰加扰内容。
本实施例适用于DCAS，尤其适用于无卡单向DCAS，增强了无卡单向DCAS的安全性。
实施例六
图6是实施例六提供的硬件安全模块的结构示意图，该硬件安全模块应用于DCAS，DCAS包括前端和终端，终端包括主芯片和所述硬件安全模块。如图6所示，硬件安全模块6包括：
第一接收单元60，用于接收主芯片发送的硬件安全模块授权管理消息和加密控制字，其中，所述硬件安全模块授权管理消息中包括用于解密所述加密控制字的密钥。
安全存储区域61，用于存储硬件安全模块根密钥、重加密密钥和所述硬件安全模块授权管理消息。
第一解密引擎62，用于根据所述硬件安全模块授权管理消息和硬件安全模 块根密钥，对所述加密控制字进行解密，得到控制字。
重加密引擎63，用于根据所述重加密密钥对所述控制字进行重加密，得到重加密控制字。
第一发送单元64，用于将所述重加密控制字发送到主芯片，以便主芯片根据所述前端发送的主芯片授权管理消息解密所述重加密控制字，得到控制字，其中，所述主芯片授权管理消息中包括用于解密所述重加密控制字的密钥。
本实施例中，硬件安全模块6还包括：
第二接收单元(图中未示出)，用于接收主芯片发送的激活消息，所述激活消息中至少包括配对密钥、所述重加密密钥和硬件安全模块根密钥；
第一配对单元(图中未示出)，用于根据所述配对密钥建立与所述主芯片的安全认证通道。
本实施例中，第一接收单元60用于：接收主芯片发送的硬件安全模块授权管理消息和加密控制字包括：通过所述安全认证通道接收主芯片发送的硬件安全模块授权管理消息和加密控制字；
第一发送单元64用于：通过所述安全认证通道将所述重加密控制字发送到主芯片。
本实施例中，所述硬件安全模块授权管理消息包括硬件安全模块二级密钥和硬件安全模块三级密钥；
本实施例中，第一解密引擎62用于：
根据所述硬件安全模块中存储的硬件安全模块根密钥、硬件安全模块二级密钥和硬件安全模块三级密钥对所述加密控制字进行层级解密，得到控制字。
本实施例中，硬件安全模块6还包括：
更新单元(图中未示出)，用于接收所述主芯片发送的密钥刷新指令，对所述硬件安全模块授权管理消息、硬件安全模块根密钥和重加密密钥进行更新和存储。
本实施例中，安全存储区域61还用于存储更新后的硬件安全模块授权管理消息、硬件安全模块根密钥和重加密密钥。
本实施例通过硬件安全模块根据存储的硬件安全模块根密钥和接收到的硬件安全模块授权管理消息对加密控制字进行解密，得到控制字，再根据硬件安全模块中存储的重加密密钥对所述控制字进行重加密，得到重加密控制字，之 后将所述重加密控制字发送到主芯片，以便主芯片根据前端发送的主芯片授权管理消息解密所述重加密控制字，得到控制字，由于外界无法从硬件安全模块中截取到解密的重要信息，从而利用该硬件安全模块增强了DCAS的安全性。此外，尤其适用于无卡单向DCAS，为无卡单向DCAS提供了安全保障。
实施例七
图7是实施例七提供的主芯片的结构示意图，该主芯片应用于DCAS，DCAS包括前端和终端，终端包括主芯片和所述硬件安全模块。如图7所示，主芯片7包括：
第三接收单元71，用于接收前端发送的加密控制字、加扰内容、主芯片授权管理消息和硬件安全模块授权管理消息；
第二发送单元72，用于将所述硬件安全模块授权管理消息和加密控制字发送至硬件安全模块，以便硬件安全模块根据所述硬件安全模块授权管理消息和硬件安全模块中存储的硬件安全模块根密钥，对所述加密控制字进行解密，得到控制字，并根据硬件安全模块中存储的重加密密钥对所述控制字进行重加密，得到重加密控制字；
第四接收单元73，用于接收硬件安全模块发送的所述重加密控制字；
第二解密引擎74，用于根据主芯片派生的主芯片根密钥和所述主芯片授权管理消息解密所述重加密控制字，得到控制字，以便根据所述控制字解扰所述加扰内容。
本实施例中，主芯片7还包括：
激活请求消息生成单元(图中未示出)，用于生成激活请求消息，将所述激活请求消息发送至前端，其中，所述激活请求消息中至少包括主芯片标识、条件接收证书和硬件安全模块的芯片证书；
激活消息接收单元(图中未示出)，用于接收前端发送的激活消息，并将所述激活消息发送至硬件安全模块，其中，所述激活消息中至少包括配对密钥、所述重加密密钥和硬件安全模块根密钥，并且所述激活消息中的配对密钥、所述重加密密钥和硬件安全模块根密钥为前端根据所述激活请求消息派发；
第二配对单元(图中未示出)，用于根据所述配对密钥建立与所述硬件安全模块的安全认证通道。
本实施例中，第二发送单元72用于：通过所述安全认证通道将所述硬件安 全模块授权管理消息和加密控制字发送至硬件安全模块。以及
第四接收单元73用于：通过所述安全认证通道接收硬件安全模块发送的所述重加密控制字。
本实施例中，主芯片7还包括：
根密钥派生单元(图中未示出)，用于根据主芯片安全密钥和派生标识，利用主芯片内置派生算法，派生出所述主芯片根密钥。
本实施例中，所述主芯片授权管理消息包括主芯片二级密钥、主芯片三级密钥；相应的，第二解密引擎74用于：
根据所述主芯片根密钥、主芯片二级密钥和主芯片三级密钥对所述重加密控制字进行层级解密，得到控制字，其中，所述主芯片三级密钥与所述重加密密钥相对应。
本实施例通过主芯片与硬件安全模块完成授权控制，从而利用该硬件安全模块增强了DCAS的安全性。并且尤其适用于无卡单向DCAS。
实施例八
图8是实施例八提供的终端的结构示意图，该终端应用于DCAS，DCAS包括前端和终端。如图8所示，终端8包括如上述实施例所述的主芯片81和硬件安全模块82，主芯片81和硬件安全模块82之间通过安全认证通道进行数据的收发，确保重要信息的安全性。
实施例九
图9是实施例九提供的硬件安全模块的结构示意图，该硬件安全模块包括：处理器910和存储器920；还可以包括通信接口930和总线940。
其中，处理器910、存储器920和通信接口930可以通过总线940完成相互间的通信。通信接口930可以用于信息传输。处理器910可以调用存储器920中的逻辑指令，以执行上述实施例的任意一种方法。
存储器920可以包括存储程序区和存储数据区，存储程序区可以存储操作系统和至少一个功能所需的应用程序。存储数据区可以存储根据电子设备的使用所创建的数据等。此外，存储器可以包括，例如，随机存取存储器的易失性存储器，还可以包括非易失性存储器。例如闪存器件或者其他非暂态固态存储器件。
本实施例还提供一种计算机可读存储介质，存储有计算机可执行指令，所 述计算机可执行指令设置为上述任一项的方法。
本实施例提供的硬件安全模块、主芯片和终端可执行上述任意实施例提供的加密控制字的保护方法，具备执行方法相应的功能模块和有益效果。
工业实用性
本公开的加密控制字的保护方法，可以保证DCAS的安全性，并使终端更安全地解密控制字并解扰音视频流。

Claims (18)

  1. 一种加密控制字的保护方法，包括：
    接收主芯片发送的硬件安全模块授权管理消息和加密控制字，其中，所述硬件安全模块授权管理消息中包括用于解密所述加密控制字的密钥；
    根据所述硬件安全模块授权管理消息和硬件安全模块中存储的硬件安全模块根密钥，对所述加密控制字进行解密，得到控制字；
    根据硬件安全模块中存储的重加密密钥对所述控制字进行重加密，得到重加密控制字；以及
    将所述重加密控制字发送到所述主芯片，以便所述主芯片根据所述前端发送的主芯片授权管理消息解密所述重加密控制字，得到所述控制字，其中，所述主芯片授权管理消息中包括用于解密所述重加密控制字的密钥。
  2. 根据权利要求1所述的方法，其中，在所述接收主芯片发送的硬件安全模块授权管理消息和加密控制字之前，还包括：
    接收所述主芯片发送的激活消息，所述激活消息中至少包括：配对密钥、所述重加密密钥和所述硬件安全模块根密钥；
    存储所述重加密密钥和所述硬件安全模块根密钥，并根据所述配对密钥建立与所述主芯片的安全认证通道；
    其中，所述接收主芯片发送的硬件安全模块授权管理消息和加密控制字包括：通过所述安全认证通道接收所述主芯片发送的所述硬件安全模块授权管理消息和所述加密控制字；以及
    所述将所述重加密控制字发送到主芯片包括：通过所述安全认证通道将所述重加密控制字发送到主芯片。
  3. 根据权利要求1或2所述的方法，其中，所述硬件安全模块授权管理消息包括硬件安全模块二级密钥和硬件安全模块三级密钥；
    根据所述硬件安全模块授权管理消息和硬件安全模块中存储的硬件安全模块根密钥，对所述加密控制字进行解密，得到控制字，包括：
    根据所述硬件安全模块中存储的所述硬件安全模块根密钥、所述硬件安全模块二级密钥和所述硬件安全模块三级密钥对所述加密控制字进行层级解密，得到所述控制字。
  4. 根据权利要求1所述的方法，还包括：
    接收所述主芯片发送的密钥刷新指令，对所述硬件安全模块授权管理消息、 所述硬件安全模块根密钥和所述重加密密钥进行更新和存储。
  5. 一种加密控制字的保护方法，包括：
    接收前端发送的加密控制字、加扰内容、主芯片授权管理消息和硬件安全模块授权管理消息；
    将所述硬件安全模块授权管理消息和所述加密控制字发送至所述硬件安全模块，以便所述硬件安全模块根据所述硬件安全模块授权管理消息和所述硬件安全模块中存储的硬件安全模块根密钥，对所述加密控制字进行解密，得到控制字，并根据所述硬件安全模块中存储的重加密密钥对所述控制字进行重加密，得到重加密控制字；以及
    接收所述硬件安全模块发送的所述重加密控制字，根据所述主芯片派生的主芯片根密钥和所述主芯片授权管理消息解密所述重加密控制字，得到所述控制字，以便根据所述控制字解扰所述加扰内容。
  6. 根据权利要求5所述的方法，在所述接收前端发送的加密控制字、加扰内容、主芯片授权管理消息和硬件安全模块授权管理消息之前，还包括：
    生成激活请求消息，将所述激活请求消息发送至所述前端，其中，所述激活请求消息中至少包括：主芯片标识、条件接收证书和所述硬件安全模块的芯片证书；
    接收所述前端发送的激活消息，并将所述激活消息发送至所述硬件安全模块，其中，所述激活消息中至少包括：配对密钥、所述重加密密钥和所述硬件安全模块根密钥，并且所述激活消息中的配对密钥、所述重加密密钥和所述硬件安全模块根密钥为所述前端根据所述激活请求消息派发；
    根据所述配对密钥建立与所述硬件安全模块的安全认证通道；
    其中，所述将所述硬件安全模块授权管理消息和加密控制字发送至硬件安全模块包括：通过所述安全认证通道将所述硬件安全模块授权管理消息和所述加密控制字发送至所述硬件安全模块；以及
    所述接收硬件安全模块发送的所述重加密控制字包括：通过所述安全认证通道接收硬件安全模块发送的所述重加密控制字。
  7. 根据权利要求5所述的方法，其中，在所述解密所述重加密控制字之前，还包括：
    根据主芯片安全密钥和派生标识，利用主芯片内置派生算法，派生出所述 主芯片根密钥。
  8. 根据权利要求5-7中任一项所述的方法，其中，所述主芯片授权管理消息包括主芯片二级密钥和主芯片三级密钥；
    所述根据主芯片派生的主芯片根密钥和所述主芯片授权管理消息解密所述重加密控制字，得到控制字，包括：
    根据所述主芯片根密钥、所述主芯片二级密钥和所述主芯片三级密钥对所述重加密控制字进行层级解密，得到所述控制字，其中，所述主芯片三级密钥与所述重加密密钥相对应。
  9. 一种硬件安全模块，配置于可下载条件接收系统，包括：
    第一接收单元，设置为接收主芯片发送的硬件安全模块授权管理消息和加密控制字，其中，所述硬件安全模块授权管理消息中包括用于解密所述加密控制字的密钥；
    安全存储区域，设置为存储硬件安全模块根密钥、重加密密钥和所述硬件安全模块授权管理消息；
    第一解密引擎，设置为根据所述硬件安全模块授权管理消息和所述硬件安全模块根密钥，对所述加密控制字进行解密，得到控制字；
    重加密引擎，设置为根据所述重加密密钥对所述控制字进行重加密，得到重加密控制字；
    第一发送单元，设置为将所述重加密控制字发送到所述主芯片，以便所述主芯片根据所述前端发送的主芯片授权管理消息解密所述重加密控制字，得到所述控制字，其中，所述主芯片授权管理消息中包括用于解密所述重加密控制字的密钥。
  10. 根据权利要求9所述的硬件安全模块，还包括：
    第二接收单元，设置为接收所述主芯片发送的激活消息，所述激活消息中至少包括配对密钥、所述重加密密钥和所述硬件安全模块根密钥；
    第一配对单元，设置为根据所述配对密钥建立与所述主芯片的安全认证通道；
    其中，所述第一接收单元设置为接收主芯片发送的硬件安全模块授权管理消息和加密控制字包括：通过所述安全认证通道接收主芯片发送的硬件安全模块授权管理消息和加密控制字；
    所述第一发送单元设置为：通过所述安全认证通道将所述重加密控制字发送到所述主芯片。
  11. 根据权利要求9或10所述的硬件安全模块，其中，所述硬件安全模块授权管理消息包括硬件安全模块二级密钥和硬件安全模块三级密钥；
    所述第一解密引擎设置为：
    根据所述硬件安全模块中存储的所述硬件安全模块根密钥、所述硬件安全模块二级密钥和所述硬件安全模块三级密钥对所述加密控制字进行层级解密，得到所述控制字。
  12. 根据权利要求9所述的硬件安全模块，还包括：
    更新单元，设置为接收所述主芯片发送的密钥刷新指令，对所述硬件安全模块授权管理消息、所述硬件安全模块根密钥和所述重加密密钥进行更新和存储；
    所述安全存储区域还设置为存储更新后的硬件安全模块授权管理消息、硬件安全模块根密钥和重加密密钥。
  13. 一种主芯片，应用于可下载条件接收系统，包括：
    第三接收单元，设置为接收前端发送的加密控制字、加扰内容、主芯片授权管理消息和硬件安全模块授权管理消息；
    第二发送单元，设置为将所述硬件安全模块授权管理消息和加密控制字发送至硬件安全模块，以便所述硬件安全模块根据所述硬件安全模块授权管理消息和所述硬件安全模块中存储的硬件安全模块根密钥，对所述加密控制字进行解密，得到控制字，并根据所述硬件安全模块中存储的重加密密钥对所述控制字进行重加密，得到重加密控制字；
    第四接收单元，设置为接收硬件安全模块发送的所述重加密控制字；
    第二解密引擎，设置为根据所述主芯片派生的主芯片根密钥和所述主芯片授权管理消息解密所述重加密控制字，得到所述控制字，以便根据所述控制字解扰所述加扰内容。
  14. 根据权利要求13所述的主芯片，还包括：
    激活请求消息生成单元，设置为生成激活请求消息，将所述激活请求消息发送至所述前端，其中，所述激活请求消息中至少包括主芯片标识、条件接收证书和硬件安全模块的芯片证书；
    激活消息接收单元，设置为接收前端发送的激活消息，并将所述激活消息发送至所述硬件安全模块，其中，所述激活消息中至少包括配对密钥、所述重加密密钥和所述硬件安全模块根密钥，并且所述激活消息中的所述配对密钥、所述重加密密钥和所述硬件安全模块根密钥为前端根据所述激活请求消息派发；
    第二配对单元，设置为根据所述配对密钥建立与所述硬件安全模块的安全认证通道；
    其中，所述第二发送单元设置为通过所述安全认证通道将所述硬件安全模块授权管理消息和所述加密控制字发送至所述硬件安全模块；以及
    所述第四接收单元设置为通过所述安全认证通道接收所述硬件安全模块发送的所述重加密控制字。
  15. 根据权利要求13所述的主芯片，还包括：
    根密钥派生单元，设置为根据主芯片安全密钥和派生标识，利用主芯片内置派生算法，派生出所述主芯片根密钥。
  16. 根据权利要求13-15中任一项所述的主芯片，其中，所述主芯片授权管理消息包括主芯片二级密钥和主芯片三级密钥；
    其中，所述第二解密引擎设置为根据所述主芯片根密钥、所述主芯片二级密钥和所述主芯片三级密钥对所述重加密控制字进行层级解密，得到所述控制字，其中，所述主芯片三级密钥与所述重加密密钥相对应。
  17. 一种终端，应用于可下载条件接收系统，包括：如权利要求9-12中任一项所述的硬件安全模块和如权利要求13-16中任一项所述的主芯片。
  18. 一种计算机可读存储介质，存储有计算机可执行指令，所述计算机可执行指令设置为权利要求1-8任一项所述的方法。
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