Social platforms are powerful tools which allow a user to communicate with their friends and family. They also allow for activists to organize and manage political movements. Unfortunately, they also allow for users to harass other users and the mitigations available for that harassment are generally lacking.
By implementing networks of consent using the techniques presented, centralized, federated and distributed social networking platforms alike can build effective mitigations against harassment. Not all techniques will be required, depending on the design and implementation of a given platform.
What does consent mean here?
In this case, consent does not have any special technical meaning. It means the same thing as it does in real life: you (or your agent) is allowing or disallowing an action concerning you in some way.
As computers are incapable of inferring whether consent is given, the user records a statement affirming their consent if granted. Otherwise, the lack of a consent statement must be taken to mean that consent was not granted for an action. How this affirmation is recorded is platform specific.
In technical terms, we refer to these affirmations of consent as an object capability. Many things in this world are already built on object capabilities, for example Mach’s port system and cryptographic assets are forms of object capabilities.
How object capabilities can be used
In a monolithic system, you don’t really need real object capabilities, as they access grants can simply be recorded in the backend, and enforced transparently.
In a federated or distributed system, there are a few techniques that can be used to represent and invoke object capabilities. For example, an object capability might be represented by a key pair. In this case, the capability is invoked by signing the request with that key. Alternatively, capability URLs are another popular option, popularized by the Second Life Grid.
In a distributed system, simply having an opaque pointer to a given set of rights (and demonstrating possession of it) is sufficient, as the actor invoking the capability will invoke it directly with all relevant participants. This works because all participants are able to directly verify the validity of the capability as they witnessed its issuance to begin with.
However, in a federated system, you also need a way to provide proof that the invocation of a capability was accepted. This is usually implemented in the form of a signed proof statement created by the participant which issued the capability to begin with. Other more exotic schemes exist, but for the purpose of explaining everything this should suffice.
Building networks of consent with object capabilities
Now that we understand the basic concepts behind object capabilities, we can use them to model what a social network built from the ground up with a consent-oriented design would look like.
It should be noted that the user may configure her user agent to automatically consent to any incoming action, but this is an implementation detail. The presence of a consent framework at the network level does not imply the requirement for a user to manage whether consent is granted, it just allows for the necessary decision points to exist.
An example on a monolithic network
Let’s say that Alice wants to reply to her friend Bob’s post on Tooter, an imaginary proprietary social network that is focused on microblogging. In a proprietary network, Alice composes her reply, and then sends it to the network. The network then asks Bob’s user agent to approve or disapprove the reply. Bob’s user agent can choose to automatically accept the reply because Alice and Bob are already friends.
Now, let’s say that Karen98734762153 wants to reply to Bob’s post as well. Karen98734762153 has no prior relationship with Bob, but because Bob’s user agent is asked to make the decision, it can present the message to Bob to accept or reject. As Karen98734762153 is wanting to suggest the use of apple-flavored horse paste as a possible prophylactic for COVID, he chooses to reject the post, and Karen98734762153 is not granted any new privileges.
The same example in a distributed system
On a proprietary network, all of this can be implemented transparently to the end user. But can it be implemented in a distributed system? In this case, we assume a simple peer to peer network like Scuttlebutt. How would this work there?
As noted before, we can use object capabilities here. In this case, both Alice and Karen98734762153 would send their replies to Bob. Alice would reference her pre-existing relationship, and Karen98734762153 would not reference anything. Bob would commit Alice’s reply to the Scuttlebutt ledger and distribute that commitment to the pub-servers he is subscribed to, and ignore Karen98734762153’s reply.
The same example in a federated system
As seen, in a distributed system with a distributed ledger, where all objects are signed, this approach can work. Federated systems are a lot trickier to get right in regards to trust relationships, but it can be done here too. In this case, we introduce proof objects to demonstrate the acceptance of a capability. We will refer to these proofs as endorsements.
To this end, both Alice and Karen98734762153 send their replies to Bob, like before. Bob’s user agent then makes the decision to accept or reject the replies. In this example, Bob would add the reply to his local copy of replies, and then at a minimum send an endorsement back to Alice. Either Alice, Bob or both would then distribute that endorsement to a list of interested subscribers, who could verify the validity of the endorsement.
While other instances may choose to accept replies without an endorsement, they can also choose to reject them, or to give endorsed replies special status in their user interface. As there is not a unified consensus mechanism in federated networks, that is all that can be done. But it’s still pretty good.
The application of these ideas to other scenarios is left as an exercise for the reader.