[keycloak-dev] Zero-knowledge proof of password?

[Bill Burke]

I think HTTP Digest was written for non-TLS connections and works similarly.

FYI, this also requires the client provide a username prior to 
authentication as you need to know the salt, algorithm, and number of 
hash iterations that were used to hash the password for that particular 
user.  To prevent attackers from guessing usernames, the client should 
always be provided with this information whether or not the username exists.

I think you could definitely implement something here.  Would be a nice 
feature for Keycloak.


On 3/9/17 8:14 AM, Peter K. Boucher wrote:
> I think if I were going to tweak it myself, I would do something patterned
> after what NTLM did:
>
> Server generates pseudo-random nonce and sends it with the ID of the
> hash-algorithm it used when storing the password:
> Server ----(hash algorithm, salt, nonce)----> Client
>
> Client hashes password with specified algorithm and salt.
> Client generates pseudo-random IV and encrypts the specified nonce, using
> the output of the hash as the key, and sends the IV and the encrypted nonce
> to the Server:
> Client ----(IV, AES block-encrypted nonce with hash as key)----> Server
>
> Server uses stored hash and specified IV to decrypt nonce, and compares
> nonce to what was sent to the Client.
>
> This way, the password is never transmitted at all, but this
> challenge-response protocol serves to prove that the Client knows the
> password.
>
> Anyway, I think my main question was answered that no one has done such a
> proof-based protocol with keycloak so far, right?
>
> -----Original Message-----
> From: keycloak-dev-bounces at lists.jboss.org
> [mailto:keycloak-dev-bounces at lists.jboss.org] On Behalf Of Bill Burke
> Sent: Wednesday, March 8, 2017 8:46 PM
> To: keycloak-dev at lists.jboss.org
> Subject: Re: [keycloak-dev] Zero-knowledge proof of password?
>
> So, you want to create the hash in the browser or proxy, then transmit
> this to Keycloak.  Keycloak compares the hash to the precalculated hash
> it has stored?  I don't see how this is any more secure.  You're still
> passing the credential (the hash) in clear text.
>
> BTW, I think other issues that make things more complex with client
> hashing is if
>
> * You need to bump up the number of hashing iterations. (recommended
> value changes every 5 years or so)
>
> * Change the hashing algorithm. (SHA-1 was just broken).
>
>
>
> On 3/8/17 6:45 PM, Niels Bertram wrote:
>> Hi Peter, your security is only ever as good as the weakest link. Given
> you transmit the password using SSL up to your VPC why would you need to
> "strengthen" (obfuscate rather) the password from there to the keycloak
> socket? From what I have seen there are 2 ways to proxy a message, 1) to
> tunnel the SSL or 2) reencrypt it in the proxy. Maybe 1) is an option for
> you as this setup would not decrypt your message ... although this comes
> with other drawbacks. I am intrigued as to what exactly you are trying to
> achieve by modifying the messages on the way though a proxy. Any chance you
> could elaborate on your security requirement?
>>> On 8 Mar. 2017, at 23:33, Peter K. Boucher <pkboucher801 at gmail.com>
> wrote:
>>> Sorry, I should have described our scenario more thoroughly.
>>>
>>> We have one of these at the border of our VPC:
>>> https://en.wikipedia.org/wiki/TLS_termination_proxy
>>>
>>> We can accept the risk of data being transmitted in the clear inside the
>>> VPC, but we would prefer that passwords not be transmitted in the clear.
>>>
>>> It's an old problem.  NTLM also used a proof of the password rather than
>>> transmitting the password for similar reasons.
>>>
>>> We could force that TLS be used inside the VPC between the TLS
> termination
>>> proxy and Keycloak, but even then, the passwords are decrypted and then
>>> re-encrypted.
>>>
>>> We are considering trying to use something like the client-side hashing
>>> described here: https://github.com/dxa4481/clientHashing
>>>
>>> The question for this group was related to whether anyone has already
>>> developed anything along these lines for use with Keycloak.
>>>
>>> Thanks!
>>>
>>>
>>> -----Original Message-----
>>> From: keycloak-dev-bounces at lists.jboss.org
>>> [mailto:keycloak-dev-bounces at lists.jboss.org] On Behalf Of Bill Burke
>>> Sent: Tuesday, March 7, 2017 6:06 PM
>>> To: keycloak-dev at lists.jboss.org
>>> Subject: Re: [keycloak-dev] Zero-knowledge proof of password?
>>>
>>> What does that even mean?  Keycloak's SSL mode can forbid non SSL
>>> connections.  FYI, OIDC requires SSL.
>>>
>>>
>>>> On 3/7/17 4:22 PM, Peter K. Boucher wrote:
>>>> Suppose you don't want your passwords transmitted in the clear after SSL
>>> is
>>>> terminated by a proxy.
>>>>
>>>>
>>>>
>>>> Has anyone developed a secure way for the client to prove they have the
>>>> password, rather than transmitting it in the body of a post?
>>>>
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