Patent Application
20200012763
Aspects of this disclosure relate to methods, apparatuses, computer programs, computer program products and systems for sharing content.
In today's technological environment, it is easy for users to share content. For example, many people carry mobile phones with camera capabilities, thus making it very easy to capture photographs and video clips for instant sharing via social media applications, such as, for example, Facebook, Snapchat etc.
Today, the way many social media applications work is that a user, using a client side social media application, creates and uploads (i.e., “posts”) to a social media server a message to be shared with the user's friends, followers etc.
The Snapchat application enables a user to capture a picture or video together with a message (collectively referred to as a “Snap”), which are sent to Snapchat friends. Snapchat temporarily collects, processes and stores the contents of the Snap (such as photos, videos and/or captions) on its servers. The contents of the Snap are also temporarily stored on the devices of recipients. Content is automatically deleted (ephemeral), from servers and devices, once all recipients have viewed the Snap.
There also exist applications that enable several users to edit and access a shared file using shared folders (Dropbox is an example of such an application). An administrator is responsible for each folder and makes sure the right people have access to the right files. Access to files is determined on a per-folder basis.
Photo editing applications (e.g., Pixlr) provides a cloud-based set of image tools and utilities, including a number of photo editors, a screen grabber browser extension, and a photo sharing service. The apps range from simple to advanced photo editing. It can be used on PCs, and on smartphones or tablets using a mobile app.
There are also a many different collaborative content creation tools (e.g., collaborative whiteboard apps) used for co-creation of documents, e-book stories, drawings, song etc. by involving others like followers, audiences, colleagues, friends etc., and as disclosed in http://contentmarketinginstitute.com/2015/09/tools-cocreate-content/, retrieved on 13 Dec. 2016.
The content sharing applications available today suffer from various drawbacks. For example, while some existing content sharing application enable online, collaborative sharing of documents, it is difficult to avoid unwanted re-publishing or sharing of the content. As another example, some content sharing applications (e.g., Snapchat) store content temporarily on devices and on a server, but such applications do not offer any guaranties that content is kept secret. Existing applications are based on centralized service control and the service providers have full control of the content and communication transactions.
This disclosure aims to overcome at least some of the drawbacks associated with today's content sharing applications. In one aspect, this disclosure enables decentralized sharing of content based on crypto protocols and distributed database technology (e.g., blockchain technology). In one aspect, the content to be shared (e.g., a photograph with captions) is encrypted and included in a session document that is stored in a distributed database that can be shared without requiring a central administrator (e.g., a blockchain or other de-centralized databases). This contrasts with traditional (SQL or NoSQL) databases that are controlled by a single entity. In some embodiments, the session document can only be manipulated by interacting with a group session agent (GSA), which may be implemented as a so called “Smart Contract.” In such embodiments, each GSA maintains a copy of the distributed database and each GSA is configured such that it will not modify the state of the database that it maintains without first reaching a consensus with other GSAs. In some embodiments, the GSA is tamper resistant due to the use of the blockchain technology. That is, no one can manipulate the session document without authorization, and, further, as no one person or entity has full control the blockchain, the blockchain can be trusted.
In some embodiments, the GSA is configured to enforce access control with respect to the session documents stored in the GSA's database. For example, an owner of content can set rules with respect to who may access, modify, and/or re-publish the content contained in a session document. Preferably, the content stored in a session document is encrypted and the GSAs do not have access to the encryption key that is needed to decrypt the content, but the encryption key is available to those whom the owner of the content provides permission to access and/or modify the content (such persons are referred to as “recipients”). With this solution, it is only the owner and recipients that are able to access and manipulate the shared content.
Accordingly, in one aspect there is provided a method for sharing content that is performed by a first group session agent (GSA). In some embodiments the method includes: obtaining, at the first GSA, session document transaction information associated with a session document transaction, wherein the session document transaction information was transmitted by a user device, and the session document transaction information comprises: a first user identifier for identifying a first user, a session document identifier for identifying a session document; an operation code for identifying an operation to be performed with respect to the session document, and a digital signature. The method further includes, the first GSA using the first user identifier to obtain an encryption key associated with the first user identifier. The method further includes the first GSA determining whether the digital signature is a valid digital signature using the obtained encryption key. The method also includes the first GSA obtaining a rule contained in the session document identified by the session document identifier. The method further includes the first GSA determining whether the rule indicates that the first user identified by the first user identifier has the authority to perform the operation on the identified session document. The method also includes, as a result of determining that the signature is valid and the rule indicates that the user has the authority to perform the operation, the first GSA transmitting to at least a subset of a set of other GSAs a transaction confirmation message comprising an indicator indicating that the session document transaction is valid, said set of other GSAs including a second GSA and a third GSA (the confirmation message may further comprise the obtained session document transaction information). The method also includes the first GSA determining the validity of the session document transaction using a distributed consensus algorithm (e.g., the first GSA determines whether at least a certain number of other GSAs included in said set of other GSAs have determined that the session document transaction is valid). The method further includes, as a result of determining that the session document transaction is valid, the first GSA performing the operation with respect to the session document.
In some embodiments, the session document comprises: i) encrypted content data that can be decrypted using a first encryption key, ii) the first user identifier, and iii) a first encrypted version of the first encryption key, wherein the first encrypted version of the first encryption key was encrypted using a second encryption key belonging to the first user (e.g., the first user's public key). In such embodiments, performing the operation with respect to the session document may include the first GSA transmitting to the first user the first encrypted version of the first encryption key and the encrypted content data. In some embodiments, the session document further comprises: an owner identifier identifying the owner of the encrypted content and a second encrypted version of the first encryption key, wherein the second encrypted version of the first encryption key was encrypted using a third encryption key associated with the owner of the encrypted content (e.g., the owner's public key).
In another aspect there is provided a GSA apparatus that is adapted to perform the above described method.
In another aspect there is provided a method for sharing content that is performed by a communication device. That is, a communication device is adapted to perform the method. In some embodiments, the method includes obtaining an indication that an owner of the content desires to share the content with a first recipient. The method further includes encrypting the content to be shared, thereby creating an encrypted version of the content to be shared, wherein the encrypted version of the content to be shared can be decrypted using a first encryption key (a.k.a., “secret” encryption key). The method also includes obtaining a second encryption key, wherein the second encryption key belongs to the first recipient. The method further includes encrypting the first encryption key using the second encryption key belonging to the first recipient, thereby creating a first encrypted version of the first encryption key. The method also includes generating a session document, wherein the session document comprises: 1) an owner identifier identifying the owner of the content, 2) a session document identifier for identifying the session document, 3) the first encrypted version of the first encryption key, 4) the encrypted version of the content to be shared, 5) and a rule comprising a first user identifier identifying the first recipient and information indicating a set of operations the first recipient may perform on the session document. The method further includes publishing the session document.
In some embodiments, the method further comprises encrypting the first encryption key using an encryption key belonging to the owner of the content, thereby creating a second encrypted version of the first encryption key, and the session document further comprises the second encrypted version of the first encryption key.
In some embodiments, publishing the session document comprises transmitting to a group session agent (GSA) a message comprising the session document. In some embodiments, publishing the session document comprises transmitting to a set of two or more GSAs the message comprising the session document. In either embodiment, the message may further comprise a digital signature for use in determining that the session document was generated on behalf of the owner of the content, wherein the digital signature was generated using a private key belonging to the owner of the content.
The above and other aspects and embodiments are described below with reference to the accompanying drawings.
The accompanying drawings, which are incorporated herein and form part of the specification, illustrate various embodiments.
As described in summary above, this disclosure enables decentralized sharing of content based on crypto protocols and distributed ledger technology (e.g., blockchain technology). In one aspect, content to be shared (e.g., a photograph with captions) is encrypted and included in a session document that is stored in a distributed database and that can be shared without requiring a central administrator. In some embodiments, the session document can only be manipulated by interacting with a group session agent (GSA). In such embodiments, each GSA maintains a copy of the distributed database and each GSA is configured such that it will not modify the state of the database that it maintains without first reaching a consensus with other GSAs
In this example shown, we shall assume that user 112 is in possession of content that user 112 would like to share with users 114 and 116. For example, user 112 may have used his communication device 102 (which in this example is a mobile phone) to take a video and user 112 wants to share the video with users 114 and 116, who are friends of user 112, and further wants to allow users 114 and 116 to add content (e.g., comments) to the video. In such a scenario, user 112 is referred to as the “owner” of the content and user 114 and 116 are referred to as the “recipients.” While user 112 is referred to as the “owner” of the content, this is not meant to imply that the user 112 necessarily possesses legal ownership of the content, rather it signifies that the user 112 is in possession of the content to be shared.
To share the content using the content sharing system 100, user 112, in some embodiments, must first install a group session app 200 (see
Thus, using
In step 404, GSC 206 encrypts the content to be shared using an encryption key, thereby creating an encrypted version of the content to be shared that can be decrypted using a first encryption key (a.k.a., the secret encryption key). The first encryption key may be identical to the encryption key used to encrypt the content, which may be a randomly generated encryption key.
In step 406, GSC 206 obtains a second encryption key belonging to the first recipient. In some embodiments, the second encryption key is the first recipient's public key.
In step 408, GSC 206 encrypts the first encryption key using the second encryption key belonging to the first recipient, thereby creating a first encrypted version of the first encryption key.
In step 410, GSC 206 generates a session document, wherein the session document comprises: 1) an owner identifier identifying the owner of the content, 2) a session document identifier for identifying the session document, 3) the first encrypted version of the first encryption key, 4) the encrypted version of the content to be shared, 5) and a rule comprising a first user identifier identifying the first recipient and information indicating a set of operations the first recipient may perform on the session document.
In step 412, GSC 206 publishes the session document. In some embodiments, GSC 206 publishes the session document by transmitting to a GSA a message comprising the session document. In other embodiments, GSC 206 publishes the session document by transmitting to a set of two or more GSAs the message comprising the session document. In some embodiments, the message further comprises a digital signature for use in determining that the session document was generated on behalf of the owner of the content, wherein the digital signature was generated using an encryption key belonging to the owner of the content, such as, for example, a private encryption key (or “private key” for short) associated with the user in the public key cryptography system (asymmetric cryptography). That is, in some embodiments, GSC 206 obtains the owner's private key and generates a digital signature using the private key using known techniques and includes the generated digital signature in the message.
In some embodiments, process 400 also includes the GSC 206 encrypting the first encryption key using an encryption key belonging to the owner of the content (see step 409) (e.g., the owner's public key), thereby creating a second encrypted version of the first encryption key, and the session document further comprises the second encrypted version of the first encryption key.
In some embodiments, the session document transaction information comprises: a first user identifier for identifying a first user; a session document identifier for identifying a session document; an operation code for identifying an operation to be performed with respect to the session document, and a digital signature. For example, the operation code may indicate that the first user desires to obtain or modify the encrypted content data that is included in the identified session document.
In some embodiments, the session document identified by the session document identifier comprises: i) encrypted content data that can be decrypted using a secret encryption key, ii) the first user identifier, and iii) a first encrypted version of the secret encryption key, wherein the first encrypted version of the secret encryption key was encrypted using an encryption key (e.g., public key) belonging to the first user. In some embodiments, the session document further comprises: an owner identifier identifying the owner of the encrypted content and a second encrypted version of the secret encryption key, wherein the second encrypted version of the secret encryption key was encrypted using an encryption key associated with the owner of the encrypted content (e.g., the owner's public key).
In step 504, the first GSA uses the first user identifier to obtain an encryption key associated with the first user identifier (e.g., the first GSA obtains a public key associated with the first user identifier).
In step 506, the first GSA uses the obtained encryption key to determine whether the digital signature is a valid digital signature. For example, in step 506, the first GSA uses the obtained encryption key to generate a digital signature and then compares this generated digital signature with the digital signature obtained in step 502. If the digital signatures match, then the obtained digital signature is a valid digital signature.
In step 508, the first GSA obtains a rule contained in the identified session document.
In step 510, the first GSA determines whether the rule indicates that the first user identified by the first user identifier has the authority to perform the operation on the identified session document (e.g., has the authority to obtain or modify the encrypted content).
In step 512, as a result of determining that the signature is valid and the rule indicates that the user has the authority to perform the operation, the first GSA transmits to at least a subset of a set of other GSAs (e.g., a second GSA and a third GSA) a transaction confirmation message comprising an indicator indicating that the session document transaction is valid.
In step 514, the first GSA determines the validity of the session document transaction using a distributed consensus algorithm such as, for example, a proof-of-work algorithm, a proof-of-stake algorithm, or a traditional distributed consensus algorithm like the practical byzantine fault tolerance algorithm. In some embodiments, determining the validity of the session document transaction using the distributed consensus algorithm comprises determining whether at least a certain number of other GSAs included in said set of other GSAs have determined that the session document transaction is valid. In some embodiments, the first GSA will determine that at least the certain number of other GSAs have determined that the session document transaction is valid by receiving from each of at least N (N>0) of the other GSAs a transaction confirmation message comprising an indicator indicating that the session document transaction is valid.
In step 516, as a result of determining that at least the certain number of other GSAs have determined that the session document transaction is valid, the first GSA performs the operation with respect to the session document stored in the first GSA's corresponding database. In some embodiments, each of the other GSA in system 100 will also perform process 500. For example, in some embodiments, each other GSA will obtain the same session document transaction information as was obtained by the first GSA in step 502. For example, in some embodiments, the transaction confirmation message transmitted by the first GSA to the other GSAs further comprises the obtained session document transaction information, and in other embodiments the GSC that transmitted the session document transaction information broadcasts the session document transaction information (e.g., transmits the session document transaction information to each GSA). In this way, the databases 131-133 will stay synchronized. Moreover, since, in some embodiments, the transaction are stored in a blockchain and each block contains the hash of the previous block, the GSAs will never come to consensus if they don't agree on previous history of transactions. In other word, they not only need to agree on the validity of new transaction but also the all previous history, which is much stronger and one of the benefits of a blockchain.
For example, if the obtained operation code indicates that the first user desires to modify the encrypted content data, then in step 516, the first GSA will modify the identified session document stored in its corresponding database and each of the other GSA's will modify the identified session document stored in its corresponding database, thereby maintaining synchronization.
As another example, in some embodiments, if the obtained operation code indicates that the first user desires to obtain the encrypted content data, then in step 516, the first GSA will obtain from the identified session document the encrypted content data and the appropriate encrypted version of the secret encryption key that is stored in the session document in association with the first user identifier (e.g., the first GSA retrieves the session document from its corresponding database and extracts the encrypted content data and the first encrypted version of the secret encryption key from the retrieved session document) and transmit the obtained encrypted content and encrypted secret encryption key to the first user's device.
In step 518 (optional), the first GSA sends an ACK to the first user's device and may also send one or more notifications. For example, if a recipient modified the encrypted content, then in step 518 the first GSA may provide a notification of this event to the owner as well as to the other recipients identified in the session document, if any. Similarly, if the owner modified the encrypted content, then in step 518 the first GSA provides a notification of this event to the recipients identified in the session document. Likewise, if an owner creates a new session document that is added to the databases 131-133, then a notification may be provided to the recipients, if any, identified in the session document.
In step 520 (optional), in the event that either the digital signature is not valid or the first user is not authorized to perform the operation, then the first GSA may send a NACK to the first user's device.
As shown in
While various embodiments of the present disclosure are described herein, it should be understood that they have been presented by way of example only, and not limitation. Thus, the breadth and scope of the present disclosure should not be limited by any of the above-described exemplary embodiments. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the disclosure unless otherwise indicated herein or otherwise clearly contradicted by context.
Additionally, while the processes described above and illustrated in the drawings are shown as a sequence of steps, this was done solely for the sake of illustration. Accordingly, it is contemplated that some steps may be added, some steps may be omitted, the order of the steps may be re-arranged, and some steps may be performed in parallel.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/SE2016/051260 | 12/15/2016 | WO | 00 |
