The problem of identity takeover
The root cause of much identity theft and fraud today is the sad fact that customer reference numbers and personal identifiers are so easy to copy. Simple numerical data like bank account numbers and health IDs can be stolen from many different sources, and replayed in bogus trans-actions.
Our personal data nowadays is leaking more or less constantly, through breached databases, websites, online forms, call centres and so on, to such an extent that customer reference numbers on their own are no longer reliable. Privacy consequentially suffers because customers are required to assert their identity through circumstantial evidence, like name and address, birth date, mother's maiden name and other pseudo secrets. All this data in turn is liable to be stolen and used against us, leading to spiralling identity fraud.
To restore the reliability of personal data, we need to know its pedigree. We need to know that an attribute presented is genuine, that it originated from a trusted authority, it's been stored safely by its owner, and it's been presented with the owner's consent.
A practical response to ID theft
Several recent breaches of government registers leave citizens vulnerable to ID theft. In Korea, the national identity card system was attacked and it seems that all Korean's citizen IDs will have to be re-issued. In the US, Social Security Numbers are often stolen and used tin fraudulent identifications; recently, SSNs of 800,000 Post Office employees appear to have been stolen along with other personal records.
We could protect people against having their stolen identifiers used behind their backs. It shouldn't be necessary to re-issue every Korean's ID. And changes could be made to improve the relibaility of identification data, without dramatically changing the backend processes. That is, if a Relying Party has always used SSN fpor instance as part of its identification regime, they could continue to do so, if only the actual Social Security Numbers being received were reliable!
The trick is to be able to tell "original" ID numbers from "copies". But what does "original" even mean in the digital world? A more precise term for what we really want is pedigree. What we need is to be able to present numerical data in such a way that the receiver may be sure of its pedigree; that is, know that the data were originally issued by an authoritative body, that the data has been kept safe, and that each presentation of the data has occured under the owner's control.
These objectives can be met with the help of smart cryptographic technologies which today are built into most smart phones and smartcards, and which are finally being properly exploited by initiatives like the FIDO Alliance.
"Notarising" personal data in chip devices
There are ways of issuing personal data to a smart chip device that prevent those data from being stolen, copied and claimed by anyone else. One way to do so is to encapsulate and notarise personal data in a unique digital certificate issued to a chip. Today, a great many personal devices routinely embody cryptographically suitable chips for this purpose, including smart phones, SIM cards, "Secure Elements", smartcards and many wearable computers.
Consider an individual named Smith to whom Organisation A has issued a unique customer reference number N. If N is saved in ordinary computer memory or a magnetic stripe, then it has no pedigree. Once the number N is presented by the cardholder in a transaction, it looks like any other number. To better safeguard N in a smartcard, it can be sealed into a digital certificate, as follows:
1. generate a fresh private-public key pair inside Smith's chip
2. export the public key
3. create a digital certificate around the public key, with an attribute corresponding to N
4. have the certificate signed by (or on behalf of) organisation A.
The result of coordinating these processes and technologies is a logical triangle that inextricably binds cardholder Smith to their reference number N and to a specific personally controlled device. The certificate signed by organisation A attests to Smith's ownership of both N and a particular key unique to the device. Keys generated inside the chip are retained internally, never divulged to outsiders. It is impossible to copy the private key to another device, so the triangle cannot be cloned, reproduced or counterfeited.
Restoring privacy and consumer control
When Smith wants to present their personal number in an electronic transaction, instead of simply copying N out of memory (at which point it would lose its pedigree), Smith's transaction software digitally signs the transaction using the certificate containing N. With standard security software, any third party can then verify that the transaction originated from a genuine chip holding the unique key certified by A as matching the number N.
Note that N doesn't have to be a customer number or numeric identifier; it could be any personal data, such as a biometric template or a package of medical information like an allergy alert.
The capability to manage multiple key pairs and certificates, and to sign transactions with a nominated private key, is increasingly built into smart devices today. By narrowing down what you need to know about someone to a precise customer reference number or similar personal data item, we will reduce identity theft and fraud while radically improving privacy. This sort of privacy enhancing technology is the key to a safe Internet of Things, and fortunately now is widely available.
Addressing ID theft
Perhaps the best thing governments could do immediately is to adopt smartcards and equivalent smart phone apps for holding and presenting ID numbers. The US government has actually come close to such a plan many times. Chip-based Social Security Cards and Medicare Cards have been proppsed before, without relaising their full potential. For these devices would best be used as above to hold a citizen's identifiers and present them cryptographically, without vulnerability to ID theft and takeover. We wouldn't have to re-issue compormised SSNs; we would instead switch from manual presentation of these numbers to automatic online presentation, with a chip card or smart phone app conveying the data through digitally signatures.
