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Re: A Proposal for Credential-based Login

From: Brent Shambaugh <brent.shambaugh@gmail.com>
Date: Mon, 17 Mar 2014 21:01:33 -0500
Message-ID: <CACvcBVp33MZS9NSQZCiTNOeZ88LteMN4BYQo42NXa3HKs1QShw@mail.gmail.com>
To: Manu Sporny <msporny@digitalbazaar.com>
Cc: Web Payments <public-webpayments@w3.org>
The other link I have is about INGA:

Loser, Alexander et al., Semantic Social Overlay Networks, IEEE Journal on
Selected Areas in Communication, Vol. 25, No. 1, January 2007

On Mon, Mar 17, 2014 at 8:59 PM, Brent Shambaugh

> Manu,
> Have you ever heard of Tribler (1)? It takes advantage of semantic
> information to improve the performance DHT. Does Telehash have these
> problems?
> (1) http://iptps06.cs.ucsb.edu/papers/Pouw-Tribler06.pdf
> On Sun, Mar 16, 2014 at 12:28 AM, Manu Sporny <msporny@digitalbazaar.com>wrote:
>> This blog post outlines some thoughts on how we could use the Identity
>> Credentials specification to also do Persona-like login for the Web. The
>> same mechanism would be used to login to websites and also deliver
>> verified credentials (such as government issued ID, shipping address
>> information):
>> http://manu.sporny.org/2014/credential-based-login/
>> The full-text of the blog post is included below for archival purposes
>> at W3C.
>> -----------------------------------------------------------------------
>> A Proposal for Credential-based Login
>>    Mozilla [1]Persona allows you to sign in to web sites using any
>>    of your existing email addresses without needing to create a new
>>    username and password on each website. It was a really promising
>>    solution for the password-based security nightmare that is login
>>    on the Web today.
>>    Unfortunately, all the paid engineers for Mozilla Persona have
>>    been [2]transitioned off of the project. While Mozilla is going to
>>    continue to support Persona into the foreseeable future, it isn't
>>    going to directly put any more resources into improving Persona.
>>    Mozilla had [3]very good reasons for doing this. That doesn't mean
>>    that the recent events aren't frustrating or sad. The Persona
>>    developers made a heroic effort. If you find yourself in the
>>    presence of Lloyd, Ben, Dan, Jed, Shane, Austin, or Jared (sorry
>>    if I missed someone!) be sure to thank them for their part in
>>    moving the Web forward.
>> If Not Persona, Then What?
>>    At the moment, the Web's future with respect to a better login
>>    experience is unclear. The current option seems to be OpenID
>>    Connect which, while implemented across millions of sites, is
>>    still not seeing the sort of adoption that you'd need for a
>>    general Web-based login. It's also [4]really complex, so complex
>>    that the lead editor of the foundation OpenID is built on left the
>>    work a long time ago in frustration.
>>    Somewhere else on the Internet, the [5]Web Payments Community
>>    Group is working on technology to build payments into the core
>>    architecture of the Web. Login and identity are a big part of
>>    payments. We need a solution that allows someone to login to a
>>    website and transmit their payment preferences at the same time. A
>>    single authorized click by you would provide your email address,
>>    shipping address, and preferred payment provider. Another
>>    authorized click by you would buy an item and have it shipped to
>>    your preferred address. There will be no need to fill out credit
>>    card information, shipping, or billing addresses and no need to
>>    create an email address and password for every site to which you
>>    want to send money. Persona was going to be this login solution
>>    for us, but that doesn't seem achievable at this point.
>> What Persona Got Right
>>    The [6]Persona after-action review that Mozilla put together is
>>    useful. If you care about identity and login, you should read it.
>>    Persona did four groundbreaking things:
>>     1. It was intended to be fully decentralized, being integrated
>>        into the browser eventually.
>>     2. It focused on privacy, ensuring that your identity provider
>>        couldn't track the sites that you were logging in to.
>>     3. It used an email address as your login ID, which is a proven
>>        approach to login on the Web.
>>     4. It was simple.
>>    It failed for at least three important reasons that were not
>>    specific to Mozilla:
>>     1. It required email providers to buy into the protocol.
>>     2. It had a temporary, centralized solution that required a
>>        costly engineering team to keep it up and running.
>>     3. If your identity provider goes down, you can't login to any
>>        website.
>>    Finally, the Persona solution did one thing well. It provided a
>>    verified email credential, but is that enough for the Web?
>> The Need for Verifiable Credentials
>>    There is a growing need for digitally verifiable credentials on
>>    the Web. Being able to prove that you are who you say you are is
>>    important when paying or receiving payment. It's also important
>>    when trying to prove that you are a citizen of a particular
>>    country, of a particular age, licensed to perform a specific task
>>    (like designing a house), or have achieved a particular goal (like
>>    completing a training course). In all of these cases, it requires
>>    the ability for you to collect digitally signed credentials from a
>>    third party, like a university, and store it somewhere on the Web
>>    in an interoperable way.
>>    The Web Payments group is working on just such a technology. It's
>>    called the [7]Identity Credentials specification.
>>    We had somewhat of an epiphany a few weeks ago when it became
>>    clear that Persona was in trouble. An email address is just
>>    another type of credential. The process for transmitting a
>>    verified email address to a website should be the same as
>>    transmitting address information or your payment provider
>>    preference. Could we apply this concept and solve the login on the
>>    web problem as well as the transmission of verified credentials
>>    problem? It turns out that the answer is: most likely, yes.
>> Verified Credential-based Web Login
>>    The process for credential-based login on the Web would more or
>>    less work like this:
>>     1. You get an account with an identity provider, or run one
>>        yourself. Not everyone wants to run one themselves, but it's
>>        the Web, you should be able to easily do so if you want to.
>>     2. You show up at a website, it asks you to login by typing in
>>        your email address. No password is requested.
>>     3. The website then kick-starts a login process via
>>        navigator.id.login() that will be driven by a Javascript
>>        polyfill in the beginning, but will be integrated into the
>>        browser in time.
>>     4. A dialog is presented to you (that the website has no control
>>        over or visibility into) that asks you to login to your
>>        identity provider. Your identity provider doesn't have to be
>>        your email provider. This step is skipped if you've logged in
>>        previously and your session with your identity provider is
>>        still active.
>>     5. A digitally signed assertion that you control your email
>>        address is given by your identity provider to the browser,
>>        which is then relayed on to the website you're logging in to.
>>    Details of how this process works can be found in the section
>>    titled [8]Credential-based Login in the Identity Credentials
>>    specification. The important thing to note about this approach is
>>    that it takes all the best parts of Persona while overcoming key
>>    things that caused its demise. Namely:
>>      * Using an innovative new technology called [9]Telehash, it is
>>        fully decentralized from day one.
>>      * It doesn't require browser buy-in, but is implemented in such
>>        a way that allows it to be integrated into the browser
>>        eventually.
>>      * It is focused on privacy, ensuring that your identity provider
>>        can't track the sites that you are logging into.
>>      * It uses an email address as your login ID, which is a proven
>>        approach to login on the Web.
>>      * It is simple, requiring far fewer web developer gymnastics
>>        than OpenID to implement. It's just one Javascript library and
>>        one navigator.id.login() call.
>>      * It doesn't require email providers to buy into the protocol
>>        like Persona did. Any party that the relying party website
>>        trusts can digitally sign a verified email credential.
>>      * If your identity provider goes down, there is still hope that
>>        you can login by storing your email credentials in a
>>        password-protected decentralized hash table on the Internet.
>> Why Telehash?
>>    There is a part of this protocol that requires the system to map
>>    your email address to an identity provider. The way Persona did it
>>    was to query to see if your email provider was a Persona Identity
>>    Provider (decentralized), and if not, the system would fall back
>>    to Mozilla's email-based verification system (centralized).
>>    Unfortunately, if Persona's verification system was down, you
>>    couldn't log into a website at all. This rarely happened, but that
>>    was more because Mozilla's team was excellent at keeping the site
>>    up and there weren't any serious attempts to attack the site. It
>>    was still a centralized solution.
>>    The Identity Credentials specification takes a different approach
>>    to the problem. It allows any identity provider to claim an email
>>    address. This means that you no longer need buy-in from email
>>    providers. You just need buy-in from identity providers, and there
>>    are a ton of them out there that would be happy to claim and
>>    verify addresses like john.doe@gmail.com, or
>>    alice.smith@ymail.com. Unfortunately, this approach means that
>>    either you need browser support, or you need some sort of mapping
>>    mechanism that maps email addresses to identity providers. Enter
>>    [10]Telehash.
>>    Telehash is an Internet-wide distributed hashtable (DHT) based on
>>    the proven [11]Kademlia protocol used by BitTorrent and Gnutella.
>>    All communication is fully encrypted. It allows you to
>>    store-and-replicate things like the following JSON document:
>> {
>>   "email": "john.doe@gmail.com",
>>   "identityService": "https://identity.example.com/identities"
>> }
>>    If you want to find out who john.doe@gmail.com's identity provider
>>    is, you just query the Telehash network. The more astute readers
>>    among you see the obvious problem in this solution, though. There
>>    are massive trust, privacy, and distributed denial of service
>>    attack concerns here.
>> Attacks on the Distributed Mapping Protocol
>>    There are four problems with the system described in the previous
>>    section.
>>    The first is that you can find out which email addresses are
>>    associated with which identity providers; that leaks information.
>>    Finding out that john.doe@gmail.com is associated with the
>>    https://identity.example.com/ identity provider is a problem.
>>    Finding out that they're also associated with the
>>    https://public.cyberwarfare.usairforce.mil/ identity provider outs
>>    them as military personnel, which turns a regular privacy problem
>>    into a national security issue.
>>    The second is that anyone on the network can claim to be an
>>    identity provider for that email address, which means that there
>>    is a big phishing risk. A nefarious identity provider need only
>>    put an entry for john.doe@gmail.com in the DHT pointing to their
>>    corrupt identity provider service and watch the personal data
>>    start pouring in.
>>    The third is that a website wouldn't know which digital signature
>>    on a email to trust. Which verified credential is trustworthy and
>>    which one isn't?
>>    The fourth is that you can easily harvest all of the email
>>    addresses on the network and spam them.
>> Attack Mitigation on the Distributed Mapping Protocol
>>    There are ways to mitigate the problems raised in the previous
>>    section. For example, replacing the email field with a hash of the
>>    email address and passphrase would prevent attackers from both
>>    spamming an email address and figuring out how it maps to an
>>    identity provider. It would also lower the desire for attackers to
>>    put fake data into the DHT because only the proper email +
>>    passphrase would end up returning a useful result to a query. The
>>    identity service would also need to be encrypted with the
>>    passphrase to ensure that injecting bogus data into the network
>>    wouldn't result in an entry collision.
>>    In addition to these three mitigations, the network would employ a
>>    high CPU/memory [12]proof-of-work to put a mapping into the DHT so
>>    the network couldn't get flooded by bogus mappings. Keep in mind
>>    that the proof-of-work doesn't stop bad data from getting into the
>>    DHT, it just slows its injection into the network.
>>    Finally, figuring out which verified email credential is valid is
>>    tricky. One could easily anoint 10 non-profit email verification
>>    services that the network would trust, or something like the
>>    certificate-authority framework, but that could be argued as
>>    over-centralization. In the end, this is more of a policy decision
>>    because you would want to make sure email verification services
>>    are legally bound to do the proper steps to verify an email while
>>    ensuring that people aren't gouged for the service. We don't have
>>    a good solution to this problem yet, but we're working on it.
>>    With the modifications above, the actual data uploaded to the DHT
>>    will probably look more like this:
>> {
>>   // SHA256 hash of john.doe@gmail.com + >15 character passphrase
>>   "id": "c8e52c34a306fe1d487a6b60b10d452bcbe268d37b0",
>>   // Proof of work for email to identity service mapping
>>   "proofOfWork": "000000000000f7322e6add42",
>>   // Passphrase-encrypted identity provider service URL
>>   "identityService": "GZtJR2B5uyH79QXCJ...s8N2B5utJR2B54m0Lt"
>> }
>>    To query the network, the customer must provide both an email
>>    address and a passphrase which are hashed together. If the hash
>>    doesn't exist on the network, then nothing is returned by
>>    Telehash.
>>    Also note that this entire Telehash-based mapping mechanism goes
>>    away once the technology is built into the browser. The telehash
>>    solution is merely a stop-gap measure until the identity
>>    credential solution is built into browsers.
>> The Far Future
>>    In the far future, browsers would communicate with your identity
>>    providers to retrieve data that are requested by websites. When
>>    you attempt to login to a website, the website would request a set
>>    of credentials. Your browser would either provide the credentials
>>    directly if it has cached them, or it would fetch them from your
>>    identity provider. This system has all of the advantages of
>>    Persona and provides realistic solutions to a number of the
>>    scalability issues that Persona suffers from.
>>    The greatest challenges ahead will entail getting a number of
>>    things right. Some of them include:
>>      * Mitigate the attack vectors for the Telehash +
>>        Javascript-based login solution. Even though the
>>        Telehash-based solution is temporary, it must be solid until
>>        browser implementations become the norm.
>>      * Ensure that there is buy-in from large companies wanting to
>>        provide credentials for people on the Web. We have a few major
>>        players in the pipeline at the moment, but we need more to
>>        achieve success.
>>      * Clearly communicate the benefits of this approach over OpenID
>>        and Persona.
>>      * Make sure that setting up your own credential-based identity
>>        provider is as simple as dropping a PHP file into your
>>        website.
>>      * Make it clear that this is intended to be a W3C standard by
>>        [13]creating a specification that could be taken
>>        standards-track within a year.
>>      * Get buy-in from web developers and websites, which is going to
>>        be the hardest part.
>> References
>>    1. http://www.mozilla.org/en-US/persona/
>>    2.
>> http://identity.mozilla.com/post/78873831485/transitioning-persona-to-community-ownership
>>    3. https://news.ycombinator.com/item?id=7362613
>>    4. http://hueniverse.com/2012/07/on-leaving-oauth/
>>    5. https://web-payments.org/
>>    6. https://wiki.mozilla.org/Identity/Persona_AAR
>>    7. https://web-payments.org/specs/source/identity-credentials/
>>    8.
>> https://web-payments.org/specs/source/identity-credentials/#web-credential-based-login
>>    9. http://telehash.org/
>>   10. http://telehash.org/
>>   11. http://en.wikipedia.org/wiki/Kademlia
>>   12. http://en.wikipedia.org/wiki/Proof_of_work
>>   13. https://web-payments.org/specs/source/identity-credentials/
>> -- manu
>> --
>> Manu Sporny (skype: msporny, twitter: manusporny, G+: +Manu Sporny)
>> Founder/CEO - Digital Bazaar, Inc.
>> blog: The Worlds First Web Payments Workshop
>> http://www.w3.org/2013/10/payments/
Received on Tuesday, 18 March 2014 02:02:02 UTC

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