Cryptography – Communication system using cryptography
Reexamination Certificate
1998-09-16
2001-06-05
Peeso, Thomas R. (Department: 2132)
Cryptography
Communication system using cryptography
C380S212000, C380S210000, C380S200000, C380S255000, C380S259000, C380S037000, C380S042000, C713S150000
Reexamination Certificate
active
06243469
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to a method and an apparatus for encrypting information in computer communication and data broadcasting, and transmitting the encrypted information.
2. Description of the Background Art
In
FIG. 25
, a conventional information transmission apparatus is shown. The conventional information transmission apparatus
1900
includes a transmitting unit
1910
, transmitter
1920
, and receiving unit
1930
. Description is now made by taking two types of specific examples, those are information transmission in the Internet as Example 1 and digital broadcasting as Example 2. A plurality of receiving units
1930
may correspond to one transmitting unit
1930
.
The transmitting unit
1930
produces transmission information It obtained by subjecting an information unit Iu to multiplexing and encryption, and output thereof. The information unit Iu is a collection of electronic data having meanings for a user, for example, such as text information, voice information, still image information, moving image information, HTML (Hypertext Makeup Language) information, and their combination.
Transmitting Unit
1910
The transmitting unit
1910
contains an information unit generator
1911
, a multiplexer
1912
, a lower layer scrambler
1913
, and a sender
1914
.
The information unit generator
1911
generates a plurality of information units Iu, and outputs thereof. In Example 1, the information unit generator
1911
outputs the information units Iu which are, for example, a text the user entered with a keyboard or the like, and an image taken into a computer, and others already stored in the computer. The information unit generator
1911
is an input screen portion of electronic mail software, and a server in a broadcasting station on the Internet, for example.
On the other hand, in Example 2, all information units Iu generated are previously stored in the information unit generator
1911
. A method for merely selectively outputting the information units Iu in accordance with a predetermined schedule is considered. The information unit generator
1911
is a broadcasting station system containing a program management system in a sending system of digital broadcasting, a cart machine of a VTR, an MPEG-2 encoder, an EPG (Electronic Program Guide) management sending system of digital broadcasting, and the like. Additional information such as EPG must be sent out with the same contents thereof maintained for a long time. Therefore, the same contents, in some cases, are repeatedly outputted in a period on the order of seconds in the information unit generator
1911
.
The multiplexer
1912
receives the plurality of information units Iu outputted by the information unit generator
1911
. Then, the multiplexer
1912
multiplexes the inputted information units Iu, and outputs the multiplexed information units Iu as multiple information Im. By the multiplexing, the plurality of information units Iu are converted into a format (multiple information lm) suitable for efficient transmission in the transmitter
1920
.
In Example 1, the multiplexer
1912
is an MIME (Multi-purpose Internet Mail Extensions) encoder used for sending multimedia information by an electronic mail on the Internet, for example. In this case, the multiplexer
1912
respectively takes text information, image information, voice information, and so forth which are the plurality of information units Iu as parts. Then the multiplexer
1912
converts the parts into a multipartite message conforming to MIME for collecting the plurality of parts, and outputs the message. The formal specification of the MIME is defined by RFC (Request for Comments) 1521/1522.
On the other hand, in Example 2, the multiplexer
1912
is a service multiplexer for obtaining TS (Transport Stream) of an MPEG-2 systems from a plurality of stream data, for example. The MPEG-2 systems and the TS are standardized by ISO/IEC CD 13818-1. In this case, the multiplexer
1912
divides each of the plurality of information units Iu outputted by the information unit generator
1911
into packets called PES (Packetized Elementary Stream), and multiplexes the obtained packets on the basis of a certain rule.
The lower layer scrambler
1913
receives the multiple information Im outputted by the multiplexer
1912
, and encrypts the multiple information Im in accordance with a predetermined encryption algorithm, and outputs the encrypted result as encrypted multiple information Ime. In Example 1, the lower layer scrambler
1913
may be software PGP (Pretty Good Privacy) on which an RSA cipher which is a public key cipher, for example, mounted therein is started with an encryption option. An output of the lower layer scrambler
1913
is a text of an electronic mail encrypted using the RSA cipher. The RSA cipher is described in detail in an article entitled by R. L. Rivest, A. Shamir, and L. Adleman which are contrivers themselves “A Method for Obtaining Digital Signatures and Public Key Cryptosystems” (Vol. 21, No. 2 issued on February, 1978 in Communications of the ACM). The PGP is described in detail in an article entitled by Simson Garfinkel “PGP: Pretty Good Privacy” (O'Reilly & Associates).
On the other hand, in Example 2, the lower layer scrambler
1913
may be, for example, a scrambler of a transport layer. The lower layer scrambler
1913
encrypts a payload portion of inputted TS of MPEG-2 using an encryption algorithm such as MULTI2 and DES(the Data Encryption Standard), and outputs the encrypted TS of the MPEG-2 which is the result thereof. Note that MULTI2 described in ARIB report No. 74 is developed by Hitachi Ltd. for the application of digital broadcasting system.
The sender
1914
receives the encrypted multiple information Ime outputted by the lower layer scrambler
1913
, and converts the encrypted multiple information Ime into transmission information It which will be inputted to the transmitter
1920
. In Example 1, the sender
1914
is a program for adding a mail header composed of a destination field, a sender field, and so forth to the text of the electronic mail. An output of the sender
1914
is the text of the electronic mail to which the mail header is added. On the other hand, in Example 2, the sender
1914
is an error-correcting encoder and a modulator for the TS of the MPEG-2.
Transmitter
1920
The transmitter
1920
transmits the inputted transmission information It to a physically distant point. Both inputs and outputs of the transmitter
1920
are the transmission information It. All the inputs of the transmitter
1920
may not appear in the outputs to the receiving unit
1930
without any error. In Example 1, the transmitter
1920
is a plurality of mail communication daemons which are connected to each other by a channel such as the Internet for interpreting and executing an SMTP (Simple Mail Transfer Protocol). Examples of the typical mail communication daemon include “sendmail”. The formal specification of the SMTP is defined by RFC 821, RFC 822, and RFC 974. The sendmail is described in detail in an article entitled by E. Allman ““SENDMAIL—An Internetwork Mail Router” Unix Programmer's manual” (CSRG U. C. Berkeley issued on July, 1983).
On the other hand, in Example 2, the transmitter
1920
is constituted by an up-converter, a parabola antenna for sending data to a satellite, a communication satellite, and a ground receiving antenna.
Receiving unit
1930
The receiving unit
1930
receives the transmission information It transmitted by the transmitter
1920
, and presents an information unit Iu to a user. The receiving unit
1930
includes a receiver
1931
, a lower layer descrambler
1932
, a demultiplexer
1933
, a reproducer
1934
, a storage
1935
, and presenter
1936
.
The receiver
1931
receives the transmission information It outputted by the transmitter
1920
, and takes out the whole or a part of thereof. Then, the receiver
1931
reproduces an encrypted multiple information Ime based on the transmission information It taken out. In Exa
Harada Takenosuke
Kataoka Mitsuteru
Machida Kazuhiro
Masuda Isao
Jack Todd
Matsushita Electric - Industrial Co., Ltd.
Peeso Thomas R.
Wenderoth , Lind & Ponack, L.L.P.
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