Enciphering apparatus and method, deciphering apparatus and method as well as information processing apparatus and method
View Patent ↗The invention provides an enciphering apparatus and method, a deciphering apparatus and method and an information processing apparatus and method by which illegal copying can be prevented with certainty. Data enciphered by a 1394 interface of a DVD player is transmitted to a personal computer and a magneto-optical disk apparatus through a 1394 bus. In the magneto-optical disk apparatus with which a change to a function is open to a user, the received data is deciphered by a 1394 interface. In contrast, in the personal computer with which a change to a function is open to a user, the enciphered data is deciphered using a time variable key by a 1394 interface, and a result of the decipherment is further deciphered using a session key by an application section.
1. An enciphering apparatus for enciphering data using a cryptographic key, comprising:
a first providing unit configured to provide a first key which is derived through an authentication process by communicating with another device;
a second providing unit configured to provide a second key which is changed during a term when said first key is used;
a producing unit configured to produce a cryptographic key based on the first key and the second key; and
an enciphering unit configured to encipher data using said cryptographic key, wherein said cryptographic key is changed at a predetermined timing during said term in accordance with a change of said second key.
2. The enciphering apparatus of claim 1 , wherein said first key and said second key are secret.
3. The enciphering apparatus of claim 2 , wherein said second key is based on information assigned to each enciphering apparatus.
4. The enciphering apparatus of claim 1 , wherein said cryptographic key is shared with a deciphering apparatus.
5. The enciphering apparatus of claim 4 , wherein said enciphering apparatus is substantially controlled by said deciphering apparatus.
6. The enciphering apparatus of claim 1 , wherein said other device is a deciphering apparatus.
7. The enciphering apparatus of claim 1 , wherein a source that provides said second key is changed to provide said second key by using seqret information shared with another device.
8. The enciphering apparatus of claim 7 , wherein said source that provides said second key is transmitted via a packet network.
9. The enciphering apparatus of claim 7 , wherein said secret information is a disturbance key to disturb the source of said second key.
10. The enciphering apparatus of claim 1 , wherein a source of said second key is extracted from a received packet.
11. The enciphering apparatus of claim 1 , further comprising a sharing unit configured to share said first key using a public key system.
12. The enciphering apparatus of claim 11 , wherein said sharing unit is configured to share said first key using a Diffie-Hellman key agreement procedure.
13. The enciphering apparatus of claim 1 , wherein said first key is derived by using an enciphering function based on information received from another device and a stored key.
14. The enciphering apparatus of claim 13 , wherein said first key is a pseudo-random number.
15. The enciphering apparatus of claim 1 , wherein said producing unit produces a cryptographic key by adding said second key into said first key.
16. The enciphering apparatus of claim 15 , wherein said adding includes an exclusive- or operation.
17. An enciphering apparatus for enciphering data using a cryptographic key, comprising:
a first providing unit configured to provide a session key which is usable for a session;
a second providing unit configured to provide a changing key which is changed during the session when said session key is used;
a producing unit configured to produce a cryptographic key based on the session key and the changing key; and
an enciphering unit configured to encipher data using said cryptographic key, wherein said cryptographic key is changed at a predetermined timing during the session in accordance with a change of said changing key.
18. The enciphering apparatus of claim 17 , wherein said session key and said changing key are secret.
19. The enciphering apparatus of claim 18 , wherein said changing key is based on information assigned to each enciphering apparatus.
20. The enciphering apparatus of claim 17 , wherein said cryptographic key is shared with a deciphering apparatus.
21. The enciphering apparatus of claim 20 , wherein said enciphering apparatus is substantially controlled by said deciphering apparatus.
22. The enciphering apparatus of claim 17 , wherein said session key is derived through an authentication process by communicating with another device and secretly shared.
23. The enciphering apparatus of claim 22 , wherein said other device is a deciphering apparatus.
24. The enciphering apparatus of claim 17 , wherein a source that provides said changing key is changed to provide said changing key by using secret information shared with another device.
25. The enciphering apparatus of claim 24 , wherein said source that provides said changing key is transmitted via a packet network.
26. The enciphering apparatus of claim 24 , wherein said secret information is a disturbance key to disturb the source of said changing key.
27. The enciphering apparatus of claim 17 , wherein a source of said changing key is extracted from a received packet.
28. The enciphering apparatus of claim 17 , further comprising a sharing unit configured to share said session key using a public key system.
29. The enciphering apparatus of claim 28 , wherein said sharing of said session key is performed using a Diffie-Hellman key agreement procedure.
30. The enciphering apparatus of claim 17 , wherein said session key is derived by using an enciphering function based on information received from another device and a stored key.
31. The enciphering apparatus of claim 30 , wherein said enciphering function is a hash function.
32. The enciphering apparatus of claim 31 , wherein said session key is a pseudo-random number.
33. The enciphering apparatus of claim 17 , wherein said producing unit produces a cryptographic key by adding said changing key into said session key.
34. The enciphering apparatus of claim 33 , wherein said adding includes an exclusive-or operation.
35. An enciphering method for enciphering data using a cryptographic key, comprising:
providing a first key which is derived through an authentication process by communicating with another device;
providing a second key which is changed during a term when said first key is used;
producing, by a processor, a cryptographic key based on the first key and the second key; and
enciphering data using said cryptographic key, wherein said cryptographic key is changed at a predetermined timing during said term in accordance with a change of said second key.
36. The enciphering method of claim 35 , wherein said first key and said second key are secret.
37. The enciphering method of claim 36 , wherein said second key is based on information assigned to each enciphering apparatus that performs the enciphering method.
38. The enciphering method of claim 35 , wherein said cryptographic key is shared with a deciphering apparatus.
39. The enciphering method of claim 38 , wherein said enciphering method is substantially controlled by said deciphering apparatus.
40. The enciphering method of claim 35 , wherein said other device is a deciphering apparatus.
41. The enciphering method of claim 35 , wherein a source that provides said second key is changed to provide said second key by using secret information shared with another device.
42. The enciphering method of claim 41 , wherein said source that provides said second key is transmitted via a packet network.
43. The enciphering method of claim 41 , wherein said secret information is a disturbance key to disturb the source of said second key.
44. The enciphering method of claim 35 , wherein a source of said second key is extracted from a received packet.
45. The enciphering method of claim 35 , further comprising sharing said first key using a public key system.
46. The enciphering method of claim 45 , wherein said first key is shared using a Diffie-Hellman key agreement procedure.
47. The enciphering method of claim 35 , wherein said first key is derived by using an enciphering function based on information received from another device and a stored key.
48. The enciphering method of claim 47 , wherein said first key is a pseudo-random number.
49. The enciphering method of claim 35 , wherein said cryptographic key is produced by adding said second key into said first key.
50. The enciphering method of claim 49 , wherein said adding includes an exclusive-or operation.
51. An enciphering method for enciphering data using a cryptographic key, comprising:
providing a session key which is usable for a session;
providing a changing key which is changed during the session when said session key is used;
producing, by a processor, a cryptographic key based on the session key and the changing key; and
enciphering data using said cryptographic key, wherein said cryptographic key is changed at a predetermined timing during the session in accordance with a change of said changing key.
52. The enciphering method of claim 51 , wherein said session key and said changing key are secret.
53. The enciphering method of claim 52 , wherein said changing key is based on information assigned to each apparatus that performs the enciphering method.
54. The enciphering method of claim 51 , wherein said cryptographic key is shared with a deciphering apparatus.
55. The enciphering method of claim 54 , wherein said enciphering method is substantially controlled by said deciphering apparatus.
56. The enciphering method of claim 51 , wherein said session key is derived through an authentication process by communicating with another device and secretly shared.
57. The enciphering method of claim 56 , wherein said other device is a deciphering apparatus.
58. The enciphering method of claim 51 , wherein a source that provides said changing key is changed to provide said changing key by using secret information shared with another device.
59. The enciphering method of claim 58 , wherein said source that provides said changing key is transmitted via a packet network.
60. The enciphering method of claim 58 , wherein said secret information is a disturbance key to disturb the source of said changing key.
61. The enciphering method of claim 51 , wherein a source of said changing key is extracted from a received packet.
62. The enciphering method of claim 51 , further comprising sharing said session key using a public key system.
63. The enciphering method of claim 62 , wherein said sharing of said session key is performed using a Diffie-Hellman key agreement procedure.
64. The enciphering method of claim 51 , wherein said session key is derived by using an enciphering function based on information received from another device and a stored key.
65. The enciphering method of claim 64 , wherein said enciphering function is a hash function.
66. The enciphering method of claim 65 , wherein said session key is a pseudo-random number.
67. The enciphering method of claim 51 , wherein said cryptographic key is produced by adding said changing key into said session key.
68. The enciphering method of claim 67 , wherein said adding includes an exclusive- or operation.
69. A non-transitory computer readable medium on which is stored instructions which, when executed by a processor performs an enciphering method for enciphering data using a cryptographic key, comprising:
providing a first key which is derived through an authentication process by communicating with another device;
providing a second key which is changed during a term when said first key is used;
producing a cryptographic key based on the first key and the second key; and
enciphering data using said cryptographic key, wherein said cryptographic key is changed at a predetermined timing during said term in accordance with a change of said second key.
70. The medium of claim 69 , wherein said first key and said second key are secret.
71. The medium of claim 70 , wherein said second key is based on information assigned to each enciphering apparatus that performs the enciphering method.
72. The medium of claim 69 , wherein said cryptographic key is shared with a deciphering apparatus.
73. The medium of claim 72 , wherein said enciphering method is substantially controlled by said deciphering apparatus.
74. The medium of claim 69 , wherein said other device is a deciphering apparatus.
75. The medium of claim 69 , wherein a source that provides said second key is changed to provide said second key by using secret information shared with another device.
76. The medium of claim 75 , wherein said source that provides said second key is transmitted via a packet network.
77. The medium of claim 75 , wherein said secret information is a disturbance key to disturb the source of said second key.
78. The medium of claim 69 , wherein a source of said second key is extracted from a received packet.
79. The medium of claim 69 , further comprising sharing said first key using a public key system.
80. The medium of claim 79 , wherein said first key is shared using a Diffie-Hellman key agreement procedure.
81. The medium of claim 69 , wherein said first key is derived by using an enciphering function based on information received from another device and a stored key.
82. The medium of claim 81 , wherein said first key is a pseudo-random number.
83. The medium of claim 69 , wherein said cryptographic key is produced by adding said second key into said first key.
84. The medium of claim 83 , wherein said adding includes an exclusive-or operation.
85. A non-transitory computer readable medium on which is stored instructions which, when executed by a processor performs an enciphering method for enciphering data using a cryptographic key, comprising:
providing a session key which is usable for a session;
providing a changing key which is changed during the session when said session key is used;
producing a cryptographic key based on the session key and the changing key; and
enciphering data using said cryptographic key, wherein said cryptographic key is changed at a predetermined timing during the session in accordance with a change of said changing key.
86. The medium of claim 85 , wherein said session key and said changing key are secret.
87. The medium of claim 86 , wherein said changing key is based on an ID assigned to each apparatus that performs the enciphering method.
88. The medium of claim 85 , wherein said cryptographic key is shared with a deciphering apparatus.
89. The medium of claim 88 , wherein said enciphering method is substantially controlled by said deciphering apparatus.
90. The medium of claim 85 , wherein said session key is derived through an authentication process by communicating with another device and secretly shared.
91. The medium of claim 90 , wherein said other device is a deciphering apparatus.
92. The medium of claim 85 , wherein a source that provides said changing key is changed to provide said changing key by using secret information shared with another device.
93. The medium of claim 92 , wherein said source that provides said changing key is transmitted via a packet network.
94. The medium of claim 92 , wherein said secret information is a disturbance key to disturb the source of said changing key.
95. The medium of claim 85 , wherein a source of said changing key is extracted from a received packet.
96. The medium of claim 85 , further comprising sharing said session key using a public key system.
97. The medium of claim 96 , wherein said sharing of said session key is performed using a Diffie-Hellman key agreement procedure.
98. The medium of claim 85 , wherein said session key is derived by using an enciphering function based on information received from another device and a stored key.
99. The medium of claim 98 , wherein said enciphering function is a hash function.
100. The medium of claim 99 , wherein said session key is a pseudo-random number.
101. The medium of claim 85 , wherein said cryptographic key is produced by adding said changing key into said session key.
102. The medium of claim 101 , wherein said adding includes an exclusive-or operation.