# US 10,311,215 B2 · Secure recording and rendering of encrypted multimedia content

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- Number: US 10,311,215 B2
- Document ID: US10311215B2
- Status: Granted
- Kind: B2
- Application number: 15/943,759
- Filed: 2018-04-03
- Published: 2018-08-09
- Granted: 2019-06-04
- Earliest claimed: 2016-05-26
- Assignees: Adobe Inc.
- Applicants: Adobe Inc.
- Inventors: Joseph Steele; John Landwehr
- Web page: https://patentgrep.com/patent/US10311215B2

## CPC

- H04L 9/088: {Usage controlling of secret information, e.g. techniques for restricting cryptographic keys to pre-authorized uses, different access levels, validity of crypto-period, different key- or password length, or different strong and weak cryptographic algorithms (network architectures or network communication protocols for using time-dependent keys in a packet data network H04L63/068)}
- H04L 9/083: {involving central third party, e.g. key distribution center [KDC] or trusted third party [TTP]}
- H04L 9/0866: {involving user or device identifiers, e.g. serial number, physical or biometrical information, DNA, hand-signature or measurable physical characteristics}
- H04L 9/3231: {Biological data, e.g. fingerprint, voice or retina (network architectures or network communication protocols for supporting authentication of entities using biometrical features in a packet data network H04L63/0861)}
- H04L 9/3234: {involving additional secure or trusted devices, e.g. TPM, smartcard, USB or software token (network architectures or network communication protocols for supporting authentication of entities using an additional device in a packet data network H04L63/0853)}
- G06F 21/107: {License processing; Key processing}
- H04L 2209/60: Digital content management, e.g. content distribution
- H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M)
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)

## Abstract

An authorized user obtains a packaging license that grants permission to use a particular recording device to generate multimedia content in accordance with specified license terms. The packaging license includes a content key that is used to encrypt the multimedia content at the point of capture on the recording device. The encrypted multimedia content can be transmitted via unsecure channels (for example, via electronic mail) to a networked content repository or an intended recipient. For playback, an authorized user obtains a playback license that grants permission to decrypt and playback the multimedia content using a particular playback device. An authorization server and a key management server are used to manage which users are entitled to receive a license, and to define the terms of the granted licenses. A record of the granted authorizations and licenses is maintained, thereby allowing access to a given content item to be audited.

## Claims

### Claim 1

A computer-implemented secure content playback method comprising:
receiving, at a playback device, from a content repository, an encrypted content item that is identified by a content item identifier, wherein the encrypted content item includes a first validation hash;
sending, from the playback device to an authorization server, a playback authorization token request that includes a user identifier and the content item identifier;
receiving, at the playback device, from the authorization server, a playback authorization token;
sending, from the playback device to a key management server, a playback license request that includes the playback authorization token and a playback device identifier associated with the playback device;
receiving, at the playback device, from the key management server, a playback license that includes a content key;
decrypting the content item using the content key;
generating a second validation hash based on the decrypted content item;
verifying that the first and second validation hashes match;
causing the decrypted content item to be rendered on a display screen associated with the playback device;
making a determination that the content item is no longer being rendered on the display screen; and
in response to making the determination, sending a notification from the playback device to the authorization server, the notification indicating that the playback license is released.

### Claim 2 (depends on 1)

The computer-implemented secure content playback method of claim 1, wherein:
the content item is encrypted using authenticated encryption; and
the playback license further includes a second key that is used to authenticate a user associated with the user identifier.

### Claim 3 (depends on 1)

The computer-implemented secure content playback method of claim 1, wherein the playback authorization token is included in the playback license received from the key management server.

### Claim 4 (depends on 1)

The computer-implemented secure content playback method of claim 1, further comprising receiving, by the playback device, a command to display the encrypted content item, wherein the playback authorization token request is sent to the authorization server in response to receiving the command.

### Claim 5 (depends on 1)

The computer-implemented secure content playback method of claim 1, wherein the encrypted content item is received from the content repository before the playback authorization token request is sent from the playback device to the authorization server.

### Claim 6 (depends on 1)

The computer-implemented secure content playback method of claim 1, wherein:
the playback license includes a validity period;
the method further comprises making a determination that the playback license has not expired based on the validity period; and
the content item is decrypted in response to making the determination.

### Claim 7 (depends on 1)

The computer-implemented secure content playback method of claim 1, wherein:
the content key is encrypted; and
the method further comprises decrypting the content key using the playback device identifier.

### Claim 8

A non-transitory computer readable medium having instructions encoded thereon that, when executed by one or more processors, cause a secure content playback process to be invoked, the process comprising:
receiving, at a playback device, from a content repository, an encrypted content item that is identified by a content item identifier, wherein the encrypted content item includes a first validation hash;
sending, from the playback device to an authorization server, a playback authorization token request that includes a user identifier and the content item identifier;
receiving, at the playback device, from the authorization server, a playback authorization token;
sending, from the playback device to a key management server, a playback license request that includes the playback authorization token and a playback device identifier associated with the playback device;
receiving, at the playback device, from the key management server, a playback license that includes a content key;
decrypting the content item using the content key;
generating a second validation hash based on the decrypted content item;
verifying that the first and second validation hashes match;
causing the decrypted content item to be rendered on a display screen associated with the playback device;
making a determination that the content item is no longer being rendered on the display screen; and
in response to making the determination, sending a notification from the playback device to the authorization server, the notification indicating that the playback license is released.

### Claim 9 (depends on 8)

The non-transitory computer readable medium of claim 8, wherein:
the playback license specifies that a secondary credential must be present for the content key to be operable;
the secure content playback process further comprises making a determination that the secondary credential is present; and
the content item is decrypted in response to making the determination.

### Claim 10 (depends on 8)

The non-transitory computer readable medium of claim 8, wherein:
the playback license includes a license term that restricts operability of the content key unless a particular user is operating the playback device; and
the secure content playback process further comprises making a determination that the particular user is operating the playback device based on a fingerprint authentication received by the playback device.

### Claim 11 (depends on 8)

The non-transitory computer readable medium of claim 8, wherein:
the playback license includes a geographical playback restriction;
the secure content playback process further comprises making a determination that the playback device is in a location that complies with the geographical playback restriction; and
the content item is decrypted in response to making the determination.

### Claim 12 (depends on 8)

The non-transitory computer readable medium of claim 8, wherein:
the playback license includes a security restriction that invalidates the playback license if the playback license has previously been released;
the secure content playback process further comprises making a determination that the playback license has not previously been released; and
the content item is decrypted in response to making the determination.

### Claim 13 (depends on 8)

The non-transitory computer readable medium of claim 8, wherein the encrypted content item is received from the content repository after the playback authorization token request is sent from the playback device to the authorization server.

### Claim 14 (depends on 8)

The non-transitory computer readable medium of claim 8, wherein the playback authorization token is (a) included in the playback license received from the key management server, and (b) encrypted with an escrow key.

### Claim 15 (depends on 8)

The non-transitory computer readable medium of claim 8, wherein:
the content key is encrypted; and
the secure content playback process further comprises decrypting the content key using the playback device identifier.

### Claim 16

A content playback device comprising:
a display screen;
a memory device; and
a processor that is operatively coupled to the display screen and the memory device, wherein the processor is configured to execute instructions stored in the memory device that, when executed, cause the processor to invoke a secure content playback process, the process comprising:
receiving, from a content repository, an encrypted content item that is identified by a content item identifier, wherein the encrypted content item includes a first validation hash;
sending, to an authorization server, a playback authorization token request that includes a user identifier and the content item identifier;
receiving, from the authorization server, a playback authorization token;
sending, to a key management server, a playback license request that includes the playback authorization token and a playback device identifier;
receiving, from the key management server, a playback license that includes a content key;
decrypting the content item using the content key;
generating a second validation hash based on the decrypted content item;
verifying that the first and second validation hashes match;
rendering the decrypted content item on the display screen;
making a determination that the content item is no longer being rendered on the display screen; and
in response to making the determination, sending a notification from the playback device to the authorization server, the notification indicating that the playback license is released.

### Claim 17 (depends on 16)

The content playback device of claim 16, wherein:
the playback license specifies that a secondary credential must be present for the content key to be operable;
the secure content playback process further comprises making a determination that the secondary credential is present; and
the content item is decrypted in response to making the determination.

### Claim 18 (depends on 16)

The content playback device of claim 16, wherein:
the content key is encrypted; and
the secure content playback process further comprises decrypting the content key using the playback device identifier.