Abstract:
Methods and systems for allowing customer or third party testing of secure programmable code are disclosed and may include verifying code loaded in a set-top box utilizing a test hash or a production hash prior to execution of the code, where the test hash and production hash may be stored in a memory, such as an OTP, within the set-top box, and may allow migration from corresponding test code to production code, which may be verified utilizing the test hash and production hash, respectively. The test and production hashes may be customer specific. The migration from test code to production code may be authenticated using at least a set-top box specific password. The test hash may be stored in a first portion of a one-time programmable memory and the production hash in a remaining portion, with the first portion being less than or equal to the remaining portion.
Abstract:
Methods and systems for preventing revocation denial of service attacks are disclosed and may include receiving and decrypting a command for revoking a secure key utilizing a hidden key, and revoking the secure key upon successful verification of a signature. The command may comprise a key ID that is unique to a specific set-top box. A key corresponding to the command for revoking the secure key may be stored in a one-time programmable memory, compared to a reference, and the security key may be revoked based on the comparison. The command for revoking the secure key may be parsed from a transport stream utilizing a hardware parser. The method and system may also comprise generating a command for revoking a secure key. The command may be encrypted and signed utilizing a hidden key and may comprise a key ID that is unique to a specific set-top box.
Abstract:
Methods and systems for protection of customer secrets in a secure reprogrammable system are disclosed, and may include controlling, via hardware logic and firmware, access to customer specific functions. The firmware may comprise trusted code, and may comprise boot code, stored in non-volatile memory, which may comprise read only memory, or a locked flash memory. A customer mode may be checked via the trusted code prior to allowing downloading of code written by a customer to the reprogrammable system. Access to customer specific functions may be restricted via commands from a trusted source. The hardware logic may be latched at startup in a disabled mode by the firmware, determined by the customer mode stored in a one time programmable memory. The customer mode may be re-checked utilizing the firmware, and may disallow the use of code other than trusted code in the reprogrammable system when the re-checking fails.
Abstract:
Methods and systems for software security in a secure communication system are disclosed and may include verifying downloaded code in a reprogrammable system and reloading prestored unmodifiable first stage code upon failure. The prestored unmodifiable first stage code, which may comprise boot code for the reprogrammable system, may be stored in locked flash, and the downloaded software code may be stored in unlocked flash. The downloaded software code may be verified by comparing a signature of the downloaded code to a private key. A first sticky bit may be utilized to indicate a failure of the verification and a second sticky bit may be utilized to indicate passing of the verification and the use of the downloaded software code. Whether to reset the reprogrammable system and reload the prestored unmodifiable first stage code may be determined from within the reprogrammable system, which may comprise a set-top box.
Abstract:
A boot code may be segmented to allow separate and independent storage of the code segments in a manner that may enable secure system boot by autonomous fetching and assembling of the boot code by a security sub-system. The code fetching may need to be done without the main CPU running on the chip for security reasons. Because the boot code may be stored in memory devices that require special software application to account for non-contiguous storage of data and/or code, for example a NAND flash memory which would require such an application as Bad Block Management, code segments stored in areas guaranteed to be usable may enable loading remaining segment separately and independently. Each of the code segments may be validated, wherein validation of the code segments may comprise use of hardware-based signatures.
Abstract:
Methods and systems for preventing revocation denial of service attacks are disclosed and may include receiving and decrypting a command for revoking a secure key utilizing a hidden key, and revoking the secure key upon successful verification of a signature. The command may comprise a key ID that is unique to a specific set-top box. A key corresponding to the command for revoking the secure key may be stored in a one-time programmable memory, compared to a reference, and the security key may be revoked based on the comparison. The command for revoking the secure key may be parsed from a transport stream utilizing a hardware parser. The method and system may also comprise generating a command for revoking a secure key. The command may be encrypted and signed utilizing a hidden key and may comprise a key ID that is unique to a specific set-top box.
Abstract:
Methods and systems for preventing revocation denial of service attacks are disclosed and may include receiving and decrypting a command for revoking a secure key utilizing a hidden key, and revoking the secure key upon successful verification of a signature. The command may comprise a key ID that is unique to a specific set-top box. A key corresponding to the command for revoking the secure key may be stored in a one-time programmable memory, compared to a reference, and the security key may be revoked based on the comparison. The command for revoking the secure key may be parsed from a transport stream utilizing a hardware parser. The method and system may also comprise generating a command for revoking a secure key. The command may be encrypted and signed utilizing a hidden key and may comprise a key ID that is unique to a specific set-top box.
Abstract:
Methods and systems for software security in a secure communication system are disclosed and may include verifying downloaded code in a reprogrammable system and reloading prestored unmodifiable first stage code upon failure. The prestored unmodifiable first stage code, which may comprise boot code for the reprogrammable system, may be stored in locked flash, and the downloaded software code may be stored in unlocked flash. The downloaded software code may be verified by comparing a signature of the downloaded code to a private key. A first sticky bit may be utilized to indicate a failure of the verification and a second sticky bit may be utilized to indicate passing of the verification and the use of the downloaded software code. Whether to reset the reprogrammable system and reload the prestored unmodifiable first stage code may be determined from within the reprogrammable system, which may comprise a set-top box.
Abstract:
Securely loading code in a security processor may include autonomous fetching an encrypted security data set, which may comprise security code and/or root keys, by a security processor integrated within a chip. The encrypted security data set may be decrypted via the on-chip security processor and the decrypted code set may be validated on-chip using an on-chip locked value. The on-chip locked value may be stored in a one-time programmable read-only memory (OTP ROM) and may include security information generated by applying one or more security algorithms, for example SHA-based algorithms, to the security data set. The encryption of the security data set may utilize various security algorithms, for example AES-based algorithms. The on-chip locked value may be created and locked after a virgin boot of a device that includes the security processor. The security data set may be authenticated during the virgin boot of the device.
Abstract:
Methods and systems for preventing revocation denial of service attacks are disclosed and may include receiving and decrypting a command for revoking a secure key utilizing a hidden key, and revoking the secure key upon successful verification of a signature. The command may comprise a key ID that is unique to a specific set-top box. A key corresponding to the command for revoking the secure key may be stored in a one-time programmable memory, compared to a reference, and the security key may be revoked based on the comparison. The command for revoking the secure key may be parsed from a transport stream utilizing a hardware parser. The method and system may also comprise generating a command for revoking a secure key. The command may be encrypted and signed utilizing a hidden key and may comprise a key ID that is unique to a specific set-top box.