Discouraging credential sharing with Mojo

[Anonymous]

Some credential issuing schemes, such as those from Brands as well as from
Camenisch & Lysyanskaya, try to avoid credential sharing by embedding
into the credential some secret which is important and valuable to the
credential holder.  Then if the credential is shared, the recipient
learns the important secret, to the detriment of the person sharing
the credential.  So he won't do it.

The problem is that there don't seem to be any secrets that will work
well in discouraging sharing.  The most obvious is a credit card number,
but this has a number of problems: some people don't have credit cards;
people could cancel their credit cards after receiving the credentia;
and underground hackers have access to thousands of stolen credit card
numbers that they don't mind sharing.

Clearly we need a new approach.  Here is a suggestion for a simple
solution which will give everyone an important secret that they will
avoid sharing.

At birth each person will be issued a secret key.  This will be called
his Mojo.  He will also get the associated public key which will assist
in protocols which involve commiting to his Mojo.  The public key can
be revealed but the Mojo should be kept secret at all costs.

Then in a credential issuing protocol, the user embeds his Mojo into
his credential in a provable way.  It is important that the protocol
not reveal the Mojo to the issuer, but rather that some kind of zero
knowledge proof be used so that the issuer is confident that sharing
the credential will reveal the Mojo.

Now all that is needed is a simple change to the law so that knowing
someone's Mojo makes him your slave.

That is, if you know someone's Mojo you own him.  You get access to all
his money and all his assets.  You can force him to work for you and
take all he earns.  You can mistreat and even kill him.  If he tries to
escape, the Runaway Mojo Slave act will commit the government to tracking
him down and returning him to you.

With this small change to the law, everyone will be gifted with an
important secret which they can use to bind and commit themselves in
a variety of protocols.  By embedding their Mojo into their secret
credentials, they can assure the credential issuer that the credential
won't be shared.  Mojo can also serve as an "is a person" credential
and allow for secure electronic voting and other protocols where each
person should only participate once.

Please join me in supporting this important reform.

Just say, "I want my Mojo!"