Blockchains use asymmetric encryption and database distribution/replication. Considering the challenges faced by those who a few years ago tried to implement public key infrastructures (PKI) we have make a giant leap! With blockchains, we now have enough evidence that a PKI infrastructure is possible. So, let’s start from there: asymmetric encryption.
Asymmetric encryption is enough to create verifiable claims: if a university creates a token with the content of a diploma and signs it with its private key, any attempt at tampering the token would invalidate the signature. Blockchains are simply redundant when claims are signed.
Now, imagine that we all owned a gizmo (I call it trust box) holding one or more key-pairs used for asymmetric encryption, we would then be able to apply our signature to every identifiable entity, whether the identifier is an email address, a URL, a public key, GPS coordinates, a picture or piece of text: take one of your private keys, encrypt the identifier (possibly augmented with a comment) and leave the matching public key next to the encrypted data and you have created a signature, that expresses a connection between you and the entity you have identified in the signature.
The connection of the public key left in a signature to a less abstract identification of oneself could be done simply by encrypting the frontpage of a chosen public representation on the web with the same private key, then leaving the matching public key plus a link to the encrypted page next to the frontpage. Web crawlers could finish the job — to connect the public keys discovered in the many signatures we have left on the Web with the chosen public representation. Alternatively we could publish this information directly into a directory. A university’s alumni page could do the trick.
This technique can be used to endorse a person (using the url of her blog if she doesn’t have a known public key) an Open Badge (it can be identified with a hash of its content) or an Amnesty International campaign to free a political prisoner (using the url of a campaign home page) etc.
Now imagine that we have issued millions of such signatures (I call them bits of trust) we would have created a high density ether, a sea of trust on which we could swim or navigate in confidence. By apposing our signature on identifiable entities, we are simultaneously contributing to the emergence of identities (ours and that of others) while expanding the milieu connecting them together.
Identities do not emerge as a set of attributes that could be isolated from their milieu but a singularity in a web of relationships. Identities have no boundaries. They are at the same time unique while encapsulating all the other existing identities. Self-sovereign identities are both individual and collective, they comprise past, present and possible futures (our aspirations).