External security module for a television signal decoder
First Claim
1. A security system for transmission of a signal comprising:
- encoder means for encoding said signal, said encoder means comprising;
signal scrambling means for scrambling signal and outputting a scrambled signal and a key for descrambling said scrambled signal;
first key encryptor means coupled to said signal scrambling means, for performing a first encryption on said key using a first confidential serial number and outputting a once-encrypted key, and second key encryptor means coupled to said first key encryptor means, for performing a further encryption on said once once-encrypted key using a second confidential serial number and outputting a twice-encrypted key, transmission means coupled to said signal scrambling means and said second key encrypted means for transmitting said scrambled signal and said twice-encrypted key, decoder means coupled to said transmission means for receiving and descrambling said scrambled signal, said decoder means comprising;
first key decryptor means coupled to said transmission means, for performing a first key decryption on said twice twice-encrypted key using said second confidential serial number and outputting a partially decrypted key, a replaceable security module, removably attached to said decoder means and containing a second key decryptor means coupled to said first key decryptor means, for performing a second key decryption on said partially decrypted key using a said first confidential serial number and outputting a decrypted key, and signal descrambling means coupled to said second key decryptor means and said transmission means for descrambling said scrambled signal using said twice-decrypted decrypted key and outputting a descrambled signal.
2 Assignments
0 Petitions
Accused Products
Abstract
A decoder for descrambling encoded satellite transmissions comprises an internal security element and a replaceable security module. The program signal is scrambled with a key and then the key itself is twice-encrypted and multiplexed with the scrambled program signal. The key is first encrypted with a first secret serial number (SSN1) which is assigned to a given replaceable security module. The key is then encrypted with a second secret serial number (SSN0) which is assigned to a given decoder. The decoder performs a first key decryption using the second secret serial number (SSN0) stored within the decoder. The partially decrypted key is then further decrypted by the replaceable security module using the first secret serial number (SSN1) stored within the replaceable security module. The decoder then descrambles the program using the twice-decrypted key. The replaceable security module can be replaced, allowing the security system to be upgraded or changed following a system breach.
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Citations
59 Claims
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1. A security system for transmission of a signal comprising:
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encoder means for encoding said signal, said encoder means comprising;
signal scrambling means for scrambling signal and outputting a scrambled signal and a key for descrambling said scrambled signal;
first key encryptor means coupled to said signal scrambling means, for performing a first encryption on said key using a first confidential serial number and outputting a once-encrypted key, and second key encryptor means coupled to said first key encryptor means, for performing a further encryption on said once once-encrypted key using a second confidential serial number and outputting a twice-encrypted key, transmission means coupled to said signal scrambling means and said second key encrypted means for transmitting said scrambled signal and said twice-encrypted key, decoder means coupled to said transmission means for receiving and descrambling said scrambled signal, said decoder means comprising;
first key decryptor means coupled to said transmission means, for performing a first key decryption on said twice twice-encrypted key using said second confidential serial number and outputting a partially decrypted key, a replaceable security module, removably attached to said decoder means and containing a second key decryptor means coupled to said first key decryptor means, for performing a second key decryption on said partially decrypted key using a said first confidential serial number and outputting a decrypted key, and signal descrambling means coupled to said second key decryptor means and said transmission means for descrambling said scrambled signal using said twice-decrypted decrypted key and outputting a descrambled signal. - View Dependent Claims (2, 3, 4, 5, 6, 9, 10, 11, 12, 13, 14, 15)
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7. A security system for transmission of a signal comprising:
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encoder means for encoding said signal, said encoder means comprising;
signal scrambling means for scrambling said signal and outputting a scrambled signal and a key for descrambling said scrambled signal, first key encryptor means coupled to said signal scrambling means, for performing a first encryption on said key using a first confidential serial number and outputting a once-encrypted key, and second key encryptor means coupled to said first key encryptor means, for performing a further encryption on said once once-encrypted key using a second confidential serial number and outputting a twice-encrypted key, transmission means coupled to said signal scrambling means and said second key encryptor means for transmitting said scrambled signal and said twice-encrypted key, decoder means coupled to said transmission means for receiving and descrambling said scrambled signal, said decoder means comprising;
a replaceable security module, removably attached to said decoder means and containing a first key decryptor means coupled to said transmission means, for performing a first key decryption on said twice twice-encrypted key using said second confidential serial number and outputting a partially decrypted key, a second key decryptor means coupled to said first key decryptor means, for performing a second key decryption on said partially decrypted key using a said first confidential serial number and outputting a decrypted key, and signal descrambling means coupled to said first second key decryptor means and said transmission means for descrambling said scrambled signal using said twice-decrypted decrypted key and outputting a descrambled signal. - View Dependent Claims (8)
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16. A decoder for receiving and descrambling a signal which has been scrambled using a key which has been subsequently twice-encrypted, said decoder comprising:
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first key decryptor means for performing a first key decryption on said twice twice-encrypted key using said a second confidential serial number and outputting a partially decrypted key, a replaceable security module, removably attached to said decoder and containing a second key decryptor means coupled to said first key decryptor means for performing a second key decryption on said partially decrypted key using a first confidential serial number and outputting a decrypted key, and signal descrambling means coupled to said second key decryptor means for descrambling said scrambled signal using said twice-decrypted decrypted key and outputting a descrambled signal. - View Dependent Claims (17, 18, 20, 21, 22, 23, 24, 25, 26, 27)
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19. A decoder for receiving and descrambling a signal which has been scrambled using a key which has been subsequently twice-encrypted, said decoder comprising:
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a replaceable security module, removably attached to said decoder and containing a first key decryptor means for performing a first key decryption on said twice twice-encrypted key using said a second confidential serial number and outputting a partially decrypted key, second key decryptor means coupled to said first key decryptor means for performing a second key decryption on said partially decrypted key using a first confidential serial number and outputting a decrypted key, and signal descrambling means coupled to said second key decryptor means for descrambling said scrambled signal using said twice-decrypted decrypted key and outputting a descrambled signal.
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28. A method of transmitting a secure signal comprising the steps of:
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scrambling said signal using a key to produce a scrambled signal, encrypting said key using a first confidential serial number to produce a once-encrypted key. key, further encrypting said once once-encrypted key using a second confidential serial number to produce a twice-encrypted key, transmitting said scrambled signal and said twice-encrypted key, receiving said scrambled signal and said twice-encrypted key in a decoder, performing a first decryption of said twice-encrypted key using said second confidential serial number to produce a partially decrypted key, performing a second decryption on said partially decrypted key in a replaceable security module removably attached to said decoder using a said first confidential serial number to produce a decrypted key, descrambling said scrambled signal using said decrypted key to produce a descrambled signal, and outputting said descrambled signal. - View Dependent Claims (29, 32, 33, 34)
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30. A method of transmitting a secure signal comprising the steps of:
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scrambling said signal using a key to produce a scrambled signal, encrypting said key using a first confidential serial number to produce a once-encrypted key, further encrypting said once once-encrypted key using a second confidential serial number to produce a twice-encrypted key, transmitting said scrambled signal and said twice-encrypted key, receiving said scrambled signal and said twice-encrypted key in a decoder, performing a first decryption of said twice-encrypted key in a replaceable security module removably attached to said decoder using said second confidential serial number to produce a partially decrypted key, performing a second decryption on said partially decrypted key using a said first confidential serial number to produce a decrypted key, descrambling said scrambled signal using said decrypted key to produce a descrambled signal, and outputting said descrambled signal. - View Dependent Claims (31)
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35. A method of decoding a signal comprising the steps of:
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receiving a scrambled signal and a twice-encrypted key in a decoder, performing a first decryption of said twice-encrypted key using a second confidential serial number to produce a partially decrypted key, performing a second decryption on said partially decrypted key in a replaceable security module removably attached to said decoder using a first confidential serial number to produce a decrypted key, descrambling said scrambled signal using said decrypted key to produce a descrambled signal, and outputting said descrambled signal. - View Dependent Claims (39, 40)
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36. A method of decoding a signal comprising the steps of:
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receiving a scrambled signal and a twice-encrypted key in a decoder, performing a first decryption of said twice-encrypted key in a replaceable security module removably attached to said securing using a second confidential serial number to produce a partially decrypted key, performing a second decryption on said partially decrypted key using a first confidential serial number to produce a decrypted key, descrambling said scrambled signal using said decrypted key to produce a descrambled signal, and outputting said descrambled signal. - View Dependent Claims (37, 38)
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41. A decoder for receiving and descrambling a signal scrambled using a twice-encrypted key, said decoder comprising:
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connector means for connecting said decoder to a replaceable security module, through which connector means said twice-encrypted key is transmitted to said replaceable security module and a partially-decrypted key is received from said replaceable security module, key decryptor means, coupled to said connector means for performing a decryption on said partially-decrypted key using a second confidential serial number, and outputting a decrypted key, and signal descrambling means coupled to said key decryptor for descrambling said signal with said decrypted key and outputting a descrambled signal. - View Dependent Claims (42, 43, 44, 45, 46, 47, 48)
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49. A decoder for receiving and descrambling a signal scrambled using a twice-encrypted key, said decoder comprising:
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key decryptor means, for performing a first key decryption on said twice-encrypted key using a first confidential serial number and outputting a partially decrypted key, connector means, coupled to said key decryptor means for connecting said decoder to a replaceable security module, through which connector means said partially decrypted key is transmitted to said replaceable security module and a descrambling control signal is received from said replaceable security module, signal descrambling means, coupled to said connector means and receiving said descrambling control signal for descrambling said signal and outputting a descrambled signal. - View Dependent Claims (50, 51, 52, 53, 54, 55)
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56. A replaceable security module for storing confidential serial number and performing a partial decryption of a twice-encrypted key and outputting a partially decrypted key, said replaceable security module comprising;
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comprising;
connector means for connecting said replaceable security module to a decoder and through which a said twice-encrypted key is received from said encoder decoder and a partially decrypted key is transmitted to said decoder, memory means for storing at least a said confidential serial number, and decryption means, coupled to said connector means and said memory means for performing a partial decryption on said twice-encrypted key and outputting a said partially-decrypted key. - View Dependent Claims (57)
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comprising;
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58. A replaceable security module for storing a secret serial number and performing a decryption of a partially decrypted key and outputting a descrambling control signal, said replaceable security module comprising;
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comprising;
connector means for connecting said replaceable security module to a decoder and through which a said partially decrypted key is received from said encoder decoder and said descrambling control signal is transmitted to said decoder, memory means for storing at least a said secret serial number, and decryption means, coupled to said connector means and said memory means for performing a decryption on said partially decrypted key and outputting a descrambling control signal. - View Dependent Claims (59)
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comprising;
Specification