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location Marseille, France
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visits member for 1 year, 4 months
seen Oct 13 '13 at 8:06

Dec
9
comment How to prove membership of a list without disclosing the list members?
I assigned you the answer because this is the solution I was looking for. Congratulation. I'm very impressed. Not only by the result, also because you didn't gave up. I was about to give up. Your solution uses only hashes with random number for perfect obfuscation to the verifier and one signature per sent message. It's PERFECT! Thank you very much.
Dec
9
awarded  Scholar
Dec
9
accepted How to prove membership of a list without disclosing the list members?
Dec
4
comment How to prove membership of a list without disclosing the list members?
If I understood correctly, a zero knowledge set is like an accumulator and is equivalent to my list of hashes. It allows a third party to probe membership and may thus indirectly leak information on the membership. However its power is to provide a much more compact member set representation than my hash list.
Dec
4
comment How to prove membership of a list without disclosing the list members?
An obvious solution is for Alice to send one distinct signed message with the same text to each member in her To: list. But this requires that Alice provides as many signatures as there are receivers (recipients) of her message. This also requires to send as many copies of the same text as there are receiver of the message. This isn't green ;) So I was searching a solution where Alice could produce one signed message with the list of receivers and send this unique message to each receiver. The receivers need that list anyway for the reply-all. The verifier must not see the message and the list
Dec
4
comment How to prove membership of a list without disclosing the list members?
I'm not sure I understood your protocol. I'm afraid there is a confusion by what I called receiver. I'm French, sorry for the inaccuracy of my language. When Alice writes the message m, she also provides a list of receivers (recipients?). These are the address list we find in the To: field of a mail. Alice will sign the message content the the address list in the To: field. The receiver Rob, will have its address in this list. Other users will too. How could Rob prove to a verifier that he is in the To: list without disclosing the other list member and the message ?
Dec
3
revised How to prove membership of a list without disclosing the list members?
added 1057 characters in body
Dec
3
awarded  Supporter
Dec
3
comment How to prove membership of a list without disclosing the list members?
Thank you very much for this answer proposal which is technically valid. Unfortunately it requires that Alice interacts with the verified which is not desirable in the messaging schema I'm implementing. Sorry for not making it clear when I presented the problem. The main reason is because the frequency of verification requests is much much lower than message sending operations and the other reason is to benefit from locality when considering a world wide communication system. Ri will communicate with a verifier close to him.
Nov
30
revised How to prove membership of a list without disclosing the list members?
added 909 characters in body
Nov
30
revised How to prove membership of a list without disclosing the list members?
added 909 characters in body
Nov
30
comment How to prove membership of a list without disclosing the list members?
I found the following article : infoscience.epfl.ch/record/128718/files/?ln=fr titled "Efficient Protocols for Set Membership and Range Proofs". Can someone explain me the algorithm ?
Nov
29
comment How to prove membership of a list without disclosing the list members?
This observation is perfectly right ! I overlooked this weakness of my solution. Since it is a communication system, it could be easy to build a list of communication pals of R1 and thus have a short list of potential R2 identity.
Nov
28
revised How to prove membership of a list without disclosing the list members?
added 8 characters in body
Nov
28
awarded  Student
Nov
27
comment How to prove membership of a list without disclosing the list members?
It means hash(a || b || c). Sorry for not using the conventional notation.
Nov
27
awarded  Editor
Nov
27
revised How to prove membership of a list without disclosing the list members?
edited title
Nov
27
asked How to prove membership of a list without disclosing the list members?