초록 ▼

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 wit

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.

대표청구항 ▼

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 sai

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 encrypted key using a second confidential serial number and outputting a 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 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 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 key and outputting a descrambled signal.