US 5,400,403 A · Abuse-resistant object distribution system and method

Abstract

Encrypted data objects are distributed via a broadcast communication channel or media. Relatively large access indicia may also be pre-distributed to any potential data object users and/or purchasers via an access communication channel or media. Subsequently, when a particular potential user or purchaser wishes to decrypt a given data object, he or she communicates to a data distribution point the identity of the desired data object and the identity of a valid access incidium. A relatively short decryption key is then furnished via a key distribution communication channel or media to permit decryption while at the same time permitting appropriate accounting operations to take place. The system is resistant to abuse in several ways but in part because such abuse would be approximately as difficult as would be re-distribution of the entire decrypted data object itself.

Claims54

Dependent claims

A data distribution unit including electronic signal processing circuits comprising:

a source of data signals m.sub.j ;
an access indicia generator means providing access indicia signals A.sub.i for selected distribution to potential users over an access channel;
a data encryptor means providing encrypted data signals c.sub.j =E.sub.j (m.sub.j) for broadcast distribution to potential users over a broadcast channel where E.sub.j is a predetermined encryption signal processing function;
and
a decryption key generator means coupled to said encryptor means and to said access indicia generator means and providing unique keys data signals t.sub.ij for selected distribution to an authorized user over a key channel such that m.sub.j =D(A.sub.i, t.sub.ij, c.sub.j) where D is a predetermined decryption signal processing function for decrypting data signals encrypted with the predetermined signal processing function E.sub.j.

2 more elements

A data distribution system comprising:

a source of data signals m.sub.j ;
an access indicia generator providing access indicia signals A.sub.i ;
a data encryptor providing encrypted data signals c.sub.j =E.sub.j (m.sub.j) where E.sub.j is a predetermined encryption signal processing function;
and
a decryption key generator coupled to said encryptor and to said access indicia generator and providing unique key signals t.sub.ij such that data signals m.sub.j =D(A.sub.i, t.sub.ij, c.sub.j) where D is a predetermined decryption signal processing function for decrypting data encrypted with the predetermined signal processing function E.sub.j ;
a plurality of terminals coupled to receive said data signals c.sub.j ;
and
each said terminal including a decryptor means adapted to receive a decryption key signal t.sub.ij based on a supplied signal A.sub.i and a selected signal c.sub.j and to provide a decryption signal m'.sub.j of the selected encrypted data.

5 more elements

A data object distribution system, comprising

(a) a broadcast channel for transmitting identical encrypted signals representing data objects from a distribution unit to a plurality of terminals;
(b) an access number channel for transmitting a unique access number signal from said distribution unit to any one of said terminals,
(c) a key distribution channel for transmitting signals representing indexes of an encrypted data object signal and of an access number signal from any one of said terminals to said distribution unit and for transmitting a key signal from the distribution unit to said one terminal which, in combination with the access number signal enables access to the data object,
(d) a distribution unit means coupled to said broadcast channel, said access number channel, and said key distribution channel, and adapted for
i. generating an access number signal A.sub.i, where i is the index of the access number signal,
ii. transmitting signal A.sub.i on said access number channel,
iii. transforming a data object signal m.sub.j into an encrypted data object signal c.sub.j, where j is the index of the data object signal,
c.sub.j =E.sub.j (m.sub.j),
and E.sub.j is a signal processing function,
iv. transmitting signal c.sub.j on said broadcast channel,
v. computing a key signal t.sub.ij such that
m.sub.j =D(A.sub.i, t.sub.ij, c.sub.j),
where D is a signal processing function,
vi. receiving signals representing index numbers i and j from said key distribution channel, and
vii. transmitting signal t.sub.ij on said key distribution channel, and
(e) a plurality of terminal means, each terminal means being coupled to said broadcast channel, said access number channel, and said key distribution channel, and adapted for
i. receiving signal c.sub.j from said broadcast channel,
ii. receiving signal A.sub.i from said access number channel,
iii. transmitting signals representing i and j on said key distribution channel, and
iv. transforming signal c.sub.j into a data object signal m'.sub.j, where
m'.sub.j =D(A.sub.i, t.sub.ij, c.sub.j).

18 more elements

A data distribution method comprising:

providing a source of data signal m.sub.j ;
providing access indicia signal A.sub.i ;
providing encrypted data signal c.sub.j =E.sub.j (m.sub.j) where E.sub.j is a predetermined encryption signal processing function;
and
providing unique key signals t.sub.ij such that m.sub.j =D(A.sub.i, t.sub.ij, c.sub.j) where D is a predetermined decryption signal processing function for decrypting data encrypted with the predetermined signal processing function E.sub.j ;
providing a plurality of terminals coupled to receive said signal c.sub.j ;
and
providing a decryptor in each terminal adapted to receive a decryption key signal t.sub.ij based on a supplied signal A.sub.i and a selected signal c.sub.j and to provide a decryption signal m'.sub.j of the selected encrypted data.

5 more elements

A data object distribution method, comprising

(a) transmitting identical encrypted signals representing data objects from a distribution unit via a broadcast channel to a plurality of terminals;
(b) transmitting a unique access number signal from said distribution unit to any one of said terminals via an access number channel,
(c) transmitting index signals of an encrypted data object and of an access number signal from any one of said terminals to said distribution unit via a key distribution channel and transmitting a key signal from the distribution unit to said one terminal which, in combination with the access number signal enables access to the data object signal,
(d) coupling a distribution unit to said broadcast channel, said access number channel, and said key distribution channel, and adapting the distribution unit for
i. generating an acess number signal A.sub.i, where signal i is the index of the access number signal,
ii. transmitting signal A.sub.i on said access number channel,
iii. transforming a data object signal m.sub.j into an encrypted data object signal c.sub.j, where signal j is the index of the data object signal,
c.sub.j =E.sub.j (m.sub.j),
and E.sub.j is a signal processing function,
iv. transmitting signal c.sub.j on said broadcast channel,
v. computing a key signal t.sub.ij such that
m.sub.j =D(A.sub.i, t.sub.ij, c.sub.j),
where D is a signal processing function,
vi. receiving signals representing index numbers i and j from said key distribution channel, and
vii. transmitting signal t.sub.ij on said key distribution channel, and
(e) coupling a plurality of terminals to said broadcast channel, said access number channel, and said key distribution channel, and adapting each terminal for
i. receiving signal c.sub.j from said broadcast channel,
ii. receiving signal A.sub.i from said access number channel,
iii. transmitting signals i and j on said key distribution channel, and
iv. transforming signal c.sub.j into a data object signal m'.sub.j, where
m'.sub.j =D(A.sub.i, t.sub.ij, c.sub.j).

18 more elements

Dependencies are inferred from the claim text.

Abuse-resistant object distribution system and method

Life of this patent

Abuse-resistant object distribution system and method

Life of this patent

Abstract

Claims54