Reproduction of secure keys by using distributed key generation data

Claim 3

A system according to Claim 1, further comprising means (108, 111) for encrypting third key generation data (105) with the first key (122) in accordance with a third encryption algorithm to produce a third key (126); means (13) for processing the third key (126) to produce the keystream (25); wherein the distributing means further distribute the third key generation data (105, 185); and a second descrambler, including means (210) for providing the second key (83); means (186) for decrypting the distributed encrypted first-key prekey (118) with the second key (83b) in accordance with the second encryption algorithm to reproduce the first-key prekey (101); means (187, 190) for encrypting the distributed first-key generation data (184) with the reproduced first-key prekey (101) in accordance with the first encryption algorithm to reproduce the first key (122); means (188, 191) for encrypting the distributed third key generation data (185) with the reproduced first key (122) in accordance with the third encryption algorithm to reproduce the third key (126); means (33) for processing the reproduced third key (126) to reproduce the keystream (25); and means (34) for processing the distributed scrambled information signal (27) with the reproduced keystream (25) to descramble the distributed scrambled information signal.

Claim 4

A system according to Claim 1, further comprising means (106, 109) for encrypting the first key generation data (103) with the second key (83b) in accordance with a third encryption algorithm to produce an encrypted first key (118); wherein the distributing means further distribute the encrypted first key (118); and a second descrambler, including means (210) for providing the second key (83); means (186) for decrypting the distributed encrypted first key (118) with the second key (83b) in accordance with the third encryption algorithm to reproduce the first key (101); means (187, 190, 188, 191, 33) for processing the reproduced first key (101) to reproduce the keystream (25); and means (34) for processing the distributed scrambled information signal (27) with the reproduced keystream (25) to descramble the distributed scrambled information signal.

Claim 5

A descrambler for descrambling a scrambled information signal produced by a system that encrypts first-key generation data (17, 104) with a first-­key prekey (18, 101) in accordance with a first encryption algorithm to produce a first key (20, 122); processes the first key to produce a keystream (25); processes the information signal (26) with the keystream to produce a scrambled information signal (27); encrypts the first-key prekey with a second key (22, 83b) in accordance with a second encryption algorithm to produce an encrypted first-key prekey (23, 118); and distributes the scrambled information signal (27), the first-key generation data (17, 104, 184) and the encrypted first-key prekey (23, 118) the descrambler comprising means (29, 210) for providing the second key; means (30, 186) for decrypting the distributed encrypted first-key prekey (23, 118) with the second key (22, 83b) in accordance with the second encryption algorithm to reproduce the first-key prekey (18, 101); means (31, 32, 187, 190) for encrypting the distributed first-key generation data (17, 184) with the reproduced first-key prekey (18, 101) in accordance with the first encryption algorithm to reproduce the first key (20, 122); means (188, 191, 33) for processing the reproduced first key (20, 122) to reproduce the keystream (25); and means (34) for processing the distributed scrambled information signal (27) with the reproduced keystream (25) to descramble the distributed scrambled information signal.

Claim 6

A descrambler for descrambling a scrambled information signal produced by a system that encrypts first-key generation data (17, 104) with a first-­key prekey (18, 101) in accordance with a first encryption algorithm to produce a first key (20, 122); processes the first key to produce a keystream (25); processes the information signal (26) with the keystream to produce a scrambled information signal (27); encrypts the first-key prekey with a second key (22, 83b) in accordance with a second encryption algorithm to produce an encrypted first-key prekey (23, 118); and distributes the scrambled information signal (27), the first-key generation data (17, 104, 184) and the encrypted first-key prekey (23, 118) the descrambler comprising means (29, 210) for providing the second key; means (30, 186) for decrypting the distributed encrypted first-key prekey (23, 118) with the second key (22, 83b) in accordance with the second encryption algorithm to reproduce the first-key prekey (18, 101); means (31, 32, 187, 190) for encrypting the distributed first-key generation data (17, 184) with the reproduced first-key prekey (18, 101) in accordance with the first encryption algorithm to reproduce the first key (20, 122); means (188, 191, 33) for processing the reproduced first key (20, 122) to reproduce the keystream (25); and means (34) for processing the distributed scrambled information signal (27) with the reproduced keystream (25) to descramble the distributed scrambled information signal.

Claim 7

A descrambler according to Claim 4 for descrambling an information signal scrambled by a said system in which the first key (122) is produced by encrypting the first-key generation data (104) with the first-key prekey (101) in accordance with the first encryption algorithm to produce encrypted first key-­generation data (120); and processing the first key generation data (104) with the encrypted first-key generation data (120) to produce the first key (122), wherein the means for reproducing the first key comprise means (187) for encrypting the distributed first-key generation data (184) with the reproduced first-key prekey (101) in accordance with the first encryption algorithm to reproduce the encrypted first-key generation data (120); and means (190) for processing the distributed first-key generation data (184) with the reproduced encrypted first-key generation data (120) to reproduce the first key (122).

Claim 8

A descrambler according to Claim 5 for descrambling an information signal scrambled by a said system in which the first key (122) is further produced by truncating the encrypted first-key generation data (120) and exclusive-ORing the truncated first-key generation data (121) with the first key generation data (104) to produce the first key (122), wherein the means for reproducing the first key comprises means (193) for truncating the encrypted first-key generation data (120; and means (190) for exclusive-ORing the truncated encrypted first-key generation data (121) with the distributed first-key generation (184) data to reproduce the first key (122).

Claim 9

A descrambler according to Claim 4 for descrambling an information signal scrambled by a said system, wherein the first-key generation data (17) includes a quantity of data that must be processed by an authorization processor (35) in the descrambler in order to enable the descrambler, and wherein said quantity of data exceeds the encryption capacity of a single operation of said first encryption algorithm; and in which system the first key (126) is produced by encrypting a first block (104) of the first-key generation data with the first-key prekey (101) in accordance with the first encryption algorithm to produce an intermediate key (122); and encrypting a second block (105) of the first-key generation data with the intermediate key (122) in accordance with a third encryption algorithm to produce the first key (126), wherein the means in the descrambler for reproducing the first key comprise means (187, 190) for encrypting said first block (184) of the distributed first-key generation data with the reproduced first-key prekey (101) in accordance with the first encryption algorithm to reproduce the intermediate key (122); and means (188, 191) for encrypting said second block (185) of the distributed first-key generation data with the reproduced intermediate key (122) in accordance with a third encryption algorithm to reproduce the first key (126); wherein the descrambler further includes an authorization processor (35) for processing the distributed first-key generation data in order to enable the descrambler.

Claim 10

A descrambler according to Claim 4 for descrambling an information signal scrambled by a said system, wherein the first-key generation data (17) includes a quantity of data that must be processed by an authorization processor (35) in the descrambler in order to enable the descrambler, and wherein said quantity of data exceeds the encryption capacity of a single operation of said first encryption algorithm; and in which system the first key (20) is produced by encrypting a first block (41, 51) of the first-key generation data (17) with the first-­key prekey (18) in accordance with the first encryption algorithm to produce a first intermediate key (42, 52); encrypting the first intermediate key (42, 52) with a second block (43, 53) of the first-key generation data in accordance with a third encryption algorithm to produce a second intermediate key (44, 54); encrypting the second intermediate key (44, 54) with a third block (45, 55) of the first-key generation data (17) in accordance with a fourth encryption algorithm to produce the first key (20), wherein the means in the descrambler for reproducing the first key comprise means (37, 47) for encrypting the first block (41, 51) of the distributed first-key generation data (17) with the reproduced first-key prekey (18) in accordance with the first encryption algorithm to reproduce the first intermediate key (42, 52); means (38, 48) for encrypting the reproduced first intermediate key (42 , 52) with the second block (43, 53) of the distributed first-key generation data (17) in accordance with the third encryption algorithm to reproduce the second intermediate key (44, 54); means (39, 49) for encrypting the reproduced second intermediate key (44, 54) with the third block (45, 55) of the distributed first-key generation data (17) in accordance with the fourth encryption algorithm to reproduce the first key (20); wherein the descrambler further includes an authorization processor (35) for processing the distributed first-key generation data (17) in order to enable the descrambler.

Claim 11

A descrambler according to Claim 4 for descrambling an information signal scrambled by a said system, wherein the first-key generation data (17) includes a quantity of data that must be processed by an authorization processor (35) in the descrambler in order to enable the descrambler, and wherein said quantity of data exceeds the encryption capacity of a single operation of said first encryption algorithm; and in which system the first key (20) is produced by encrypting a first block (65) of the first-key generation data (17) with the first-key prekey (18) in accordance with the first encryption- algorithm to produce a first intermediate key (66); processing a second block (67) of the first-key generation data (17) with the first intermediate key (66); to produce a preencrypted second block of data (68); encrypting the preencrypted second block of data (68) a third block (69) of the first-key generation data (17) in accordance with a third encryption algorithm to produce an encrypted second block of data (70); processing the encrypted second block of data (70) with the second block of data (67) to produce a second intermediate key (71); processing a fourth block (72) of the first-key generation data (17) with the second intermediate key (71) to produce a preencrypted fourth block of data (73); encrypting the preencrypted fourth block of data (73) with a fifth block (74) of the first-key generation data (17) in accordance with a fourth encryption algorithm to produce an encrypted fourth block of data (75); and processing the encrypted fourth block of data (75) with the fourth block of data (72) to produce the first key (20), wherein the means in the descrambler for reproducing the first key comprise means (57) for encrypting the first block (65) of the distributed first-key generation data (17) with the reproduced first-key prekey (18) in accordance with the first encryption algorithm to reproduce the first intermediate key (66); means (60) for processing the second block (67) of the distributed first-key generation data (17) with the reproduced first intermediate key (66) to reproduce the preencrypted second block of data (68); means (58) for encrypting the reproduced preencrypted second block of data (68) with the third block (69) of the distributed first-key generation data (17) in accordance with the third encryption algorithm to reproduce the encrypted second block of data (70); means (61) for processing the reproduced encrypted second block of data (70) with the second block of data (67) to reproduce a second intermediate key (71); means (62) for processing the fourth block (72) of the distributed first-key generation data (17) with the reproduced second intermediate key (71) to reproduce the preencrypted fourth block of data (73); means (59) for encrypting the reproduced preencrypted fourth block of data (73) with the fifth block (74) of the distributed first-key generation data (17) in accordance with the fourth encryption algorithm to reproduce the encrypted fourth block of data (75); and means (63) for processing the reproduced encrypted fourth block of data (75) with the fourth block of data (72) to reproduce the first key (20); wherein the descrambler further includes an authorization processor (35) for processing the distributed first-key generation data (17) in order to enable the descrambler.

Claim 12

A descrambler according to Claim 4 for descrambling an information signal scrambled by a said system in which the first-key generation data (17) includes a sequence number (81) associated with the second key (83), wherein the means (210, 214) for providing the second key (83) include means for processing the distributed sequence number (81) to provide the second key (83),

Claim 13

A descrambler according to Claim 4 or 10 for descrambling an information signal scrambled by a said system in which the key generation data (17) further includes a key index (82) used for accessing data (200) processed to provide the second key (83) in the descrambler, wherein the means (202, 210) for providing the second key (83) further include means (202) for processing the distributed key index (82) to provide the second key (83).

Claim 14

A descrambler according to Claim 4 for descrambling an information signal scrambled by a said system in which the first key (122) is processed to produce the keystream (25) by encrypting third key generation data (105) with the first key (122) in accordance with a third encryption algorithm to produce a third key (126); and the third key (126) is processed to produce the keystream (25); and the third key generation data (105, 185) is also distributed, wherein the means for processing the reproduced first key (122) to reproduce the keystream, comprise means (188, 191) for encrypting the distributed third key generation data (185) with the reproduced first key (122) in accordance with the third encryption algorithm to reproduce the third key (126); and means (33) for processing the reproduced third key (126) to reproduce the keystream (25).

Claim 15

A descrambler according to Claim 4 for descrambling an information signal scrambled by a said system in which first-key prekey generation data (87) is encrypted with a first-key prekey (84) prekey in accordance with a third encryption algorithm to produce the first-key prekey (101); the first-key prekey prekey (84) is encrypted with the second key (83a) in accordance with a fourth encryption algorithm to produce an encrypted first-key prekey prekey (97); and the encrypted first-key prekey prekey (97), the first-key prekey generation data (87, 167) and a descrambler category identification number (80) are also distributed, wherein the descrambler further comprises means (167) for decrypting the distributed encrypted first-key prekey prekey (97) with the second key (83a) in accordance with the fourth encryption algorithm to reproduce the first-key prekey prekey (84); means (169, 171) for encrypting the distributed first-key prekey generation data (167) with the reproduced first-key prekey prekey (84) in accordance with the third encryption algorithm to reproduce the first-key prekey; and (101); switching means (162) responsive to the distributed descrambler category identification number (80) for causing the first-key prekey (101) that is used to encrypt the distributed first-key generation data (184) to be reproduced by either (a) decrypting the distributed encrypted first-key prekey (118) with the second key (83b) in accordance with the second algorithm or (b) decrypting the distributed encrypted first-key prekey prekey (97) with the second key (83a) in accordance with the fourth algorithm to reproduce the first-key prekey prekey (84) and encrypting the distributed first-key prekey generation data (167) with the reproduced first-key prekey prekey (84) in accordance with the third algorithm.