Re: [tor-dev] Temporary hidden services

2018-10-22 Thread Michael Rogers
On 19/10/2018 16:05, Leif Ryge wrote: > On Wed, Oct 17, 2018 at 07:27:32PM +0100, Michael Rogers wrote: > [...] >> If we decided not to use the key blinding trick, and just allowed both >> parties to know the private key, do you see any attacks? > [...] > > If I'm understanding your proposal corr

Re: [tor-dev] Temporary hidden services

2018-10-22 Thread Michael Rogers
On 19/10/2018 14:01, George Kadianakis wrote: > Michael Rogers writes: >> A given user's temporary hidden service addresses would all be related >> to each other in the sense of being derived from the same root Ed25519 >> key pair. If I understand right, the security proof for the key blinding >>

Re: [tor-dev] Temporary hidden services

2018-10-19 Thread Leif Ryge
On Wed, Oct 17, 2018 at 07:27:32PM +0100, Michael Rogers wrote: [...] > If we decided not to use the key blinding trick, and just allowed both > parties to know the private key, do you see any attacks? [...] If I'm understanding your proposal correctly, I believe it would leave you vulnerable to

Re: [tor-dev] Temporary hidden services

2018-10-19 Thread George Kadianakis
Michael Rogers writes: > On 18/10/2018 13:26, George Kadianakis wrote: >> Michael Rogers writes: >> >>> Hi George, >>> >>> On 15/10/2018 19:11, George Kadianakis wrote: Nick's trick seems like a reasonable way to avoid the issue with both parties knowing the private key. >>> >>>

Re: [tor-dev] Temporary hidden services

2018-10-19 Thread Michael Rogers
On 18/10/2018 13:26, George Kadianakis wrote: > Michael Rogers writes: > >> Hi George, >> >> On 15/10/2018 19:11, George Kadianakis wrote: >>> Nick's trick seems like a reasonable way to avoid the issue with both >>> parties >>> knowing the private key. >> >> Thanks! Good to know. Any thoughts a

Re: [tor-dev] Temporary hidden services

2018-10-18 Thread George Kadianakis
Michael Rogers writes: > Hi George, > > On 15/10/2018 19:11, George Kadianakis wrote: >> Nick's trick seems like a reasonable way to avoid the issue with both parties >> knowing the private key. > > Thanks! Good to know. Any thoughts about how to handle the conversion > between ECDH and EdDSA key

Re: [tor-dev] Temporary hidden services

2018-10-17 Thread Michael Rogers
Hi George, On 15/10/2018 19:11, George Kadianakis wrote: > Nick's trick seems like a reasonable way to avoid the issue with both parties > knowing the private key. Thanks! Good to know. Any thoughts about how to handle the conversion between ECDH and EdDSA keys? If we decided not to use the key

Re: [tor-dev] Temporary hidden services

2018-10-15 Thread George Kadianakis
Michael Rogers writes: > Hi all, > > The Briar team is working on a way for users to add each other as > contacts by exchanging links without having to meet in person. > > We don't want to include the address of the user's long-term Tor hidden > service in the link, as we assume the link may be o

Re: [tor-dev] Temporary hidden services

2018-10-01 Thread Michael Rogers
On 28/09/2018 02:40, Nick Mathewson wrote: > On Thu, Sep 27, 2018 at 9:26 AM Michael Rogers > wrote: >> >> Hi all, >> >> The Briar team is working on a way for users to add each other as >> contacts by exchanging links without having to meet in person. >> >> We don't want to include the address o

Re: [tor-dev] Temporary hidden services

2018-10-01 Thread Michael Rogers
Hi Chad, On 27/09/2018 20:02, Chad Retz wrote: > I am no expert here, but I'm confused by "the client connecting to the > service knows the service's private key". Why not just create an onion > service (per contact) and then use the client authentication feature > to ensure they share the same se

Re: [tor-dev] Temporary hidden services

2018-09-27 Thread meejah
In this realm, perhaps https://github.com/warner/magic-wormhole could be used to construct a solution? Some person has to "initiate" the wormhole and pass the (short) code to the other person -- this could be via some established channel, like "over the phone" (the codes exchanged are only usable

Re: [tor-dev] Temporary hidden services

2018-09-27 Thread Nick Mathewson
On Thu, Sep 27, 2018 at 9:26 AM Michael Rogers wrote: > > Hi all, > > The Briar team is working on a way for users to add each other as > contacts by exchanging links without having to meet in person. > > We don't want to include the address of the user's long-term Tor hidden > service in the link

Re: [tor-dev] Temporary hidden services

2018-09-27 Thread Chad Retz
I am no expert here, but I'm confused by "the client connecting to the service knows the service's private key". Why not just create an onion service (per contact) and then use the client authentication feature to ensure they share the same secret? Client auth is built in to discovery and from what

[tor-dev] Temporary hidden services

2018-09-27 Thread Michael Rogers
Hi all, The Briar team is working on a way for users to add each other as contacts by exchanging links without having to meet in person. We don't want to include the address of the user's long-term Tor hidden service in the link, as we assume the link may be observed by an adversary, who would th