Obtaining a signed rights label (SRL) for digital content and obtaining a digital license corresponding to the content based on the SRL in a digital rights management system

A method for providing a digital license from a license server to a user, the license for allowing the user to render corresponding published digital content, the content being encrypted according to a content key (CK) to result in (CK(content)), (CK(content)) being accompanied by a signed rights label (SRL) including (CK) protected according to a public key for the license server (PU-DRM), rights data protected according to (PU-DRM), and a digital signature based on a private key (PR-DRM) corresponding to (PU-DRM) and based at least in part on the protected rights data, the method comprising:

• receiving the SRL and a user key as part of a request for the license from the user;
• accessing the signature in the SRL;
• verifying the signature based on (PU-DRM) and based at least in part on the protected rights data;
• accessing the protected rights data in the SRL;
• reviewing the accessed rights data to determine whether the user is entitled to the license;
• and
• if so:
• accessing the protected (CK) in the SRL;
• protecting the accessed (CK) according to the received user key;
• and
• issuing the license to the user, the license including (CK) protected according to the user key, whereby the user can access (CK) from the license and apply (CK) to (CK(content)) to result in the content.

A method in combination with digital content and a digital license corresponding to the content and issued by a license server to a user to render the content,

• the content being encrypted according to a content key (CK) to result in (CK(content)), (CK(content)) being accompanied by a signed rights label (SRL) including (CK) encrypted according to a symmetric key (DES1) to result in (DES1(CK)), rights data encrypted according to the symmetric key (DES1) to result in (DES1(rightsdata)), (DES1) encrypted according to a public key for the license server (PU-DRM) to result in (PU-DRM(DES1)), and a digital signature based on a private key (PR-DRM) corresponding to (PU-DRM) and based at least in part on (DES1(rightsdata)),
• the license including (CK) protected according to a user key, whereby the user can access (CK) from the license and apply (CK) to (CK(content)) to result in the content, the license further including (DES1) encrypted according to the user key,
• the method for the user to alter the rights data in the SRL and comprising:
• retrieving (DES1) encrypted according to the user key from the license;
• decrypting (DES1) encrypted according to the user key to result in (DES1);
• retrieving (DES1(rightsdata)) from the SRL;
• applying (DES1) to (DES1(rightsdata)) to result in the rights data;
• altering the rights data as desired;
• encrypting the altered rights data according to (DES1) to result in (DES1(alteredrightsdata))
• submitting (DES1(alteredrightsdata)) and (DES1(CK)) as a republished rights label to the license server for signing thereby, the license server validating the republished rights label and, if valid, creating a digital signature based on (PR-DRM) and based at least in part on (DES1(alteredrightsdata)) to result in a signed republished rights label (SRRL) and returning the SRRL;
• receiving the returned SRRL and concatenating such received SRRL with (CK(content)) to form a content package;
• and
• distributing the content package to one or more users, whereby a user desiring to render the content retrieves the SRRL from the content package and submits the retrieved SRRL to the license server as part of a request for a license corresponding to the content, whereby the license server verifying the signature of the SRRL based on (PU-DRM) and based at least in part on (DES1(alteredrightsdata)), accesses (DES1(alteredrightsdata)) in the SRRL and reviews same to determine whether the user is entitled to the license, and if so issues the license to the user, the license including (CK) in a protected form accessible to the user.

A method of self-publishing digital content to enable a license server to issue a digital license corresponding to the content to one or more users desiring to render the content, the method comprising:

• receiving from the license server an authorizing certificate including a public key (PU-CERT) and a corresponding private key (PR-CERT) encrypted according to a public key of the user (PU-USER) to result in (PU-USER(PR-CERT), the certificate being signed by a private key of the license server (PR-DRM);
• encrypting the content according to a content key (CK) to result in (CK(content));
• protecting the content key (CK) according to a public key of the license server (PU-DRM) corresponding to (PR-DRM);
• generating rights data associated with the content;
• protecting the rights data according to (PU-DRM);
• submitting the protected rights data and the protected content key (CK)) as a rights label;
• obtaining (PR-CERT) from the received authorizing certificate;
• signing the submitted rights label with the obtained (PR-CERT) based at least in part on the protected rights data to result in a signed rights label (SRL);
• concatenating the SRL and the authorizing certificate with (CK(content)) to form a content package;
• and
• distributing the content package to the one or more users, whereby a user desiring to render the content retrieves the SRL and the authorizing certificate from the content package and submits the retrieved SRL and certificate to the license server as part of a request for the license corresponding to the content, whereby the license server verifies the signature of the certificate based on (PU-DRM), obtains (PU-CERT) from the certificate, verifies the signature of the SRL based on the obtained (PU-CERT), accesses the protected rights data in the SRL and reviews same to determine whether the user is entitled to the license, and if so issues the license to the user, the license including (CK) in a protected form accessible to the user.