Forking this @peg's thread

Here is what was said:

my understanding is:

seed -> hash function -> private key -> hash function -> master public key (which is what we were sharing)

in my understanding its not a good idea to share public key as if someone had say a quantum computer they might be able to get you private key from it and spend your funds. Which is why electrum generates addresses for recieving rather than using public key (as well as for privacy so ppl cant see how much money you have).

but if you share your seed, you are sharing your private key. which is more dangerous. If your computer breaks all you need is your seed to get access to your money back.

it could be that i have misunderstood something though....

Am actually trying to get to the bottom of my assumptions as the question made me realise that I was basing the assumption on the GUI of electrum which says 'Share Seed or Masterkey'.

Have been digging into the guts here:

http://docs.electrum.org/en/latest/multisig.html
http://docs.electrum.org/en/latest/seedphrase.html

@peg do you have links to resources from which you derived your understanding. It's an important point that we should figure out!

Hey @peg , have run through the electrum multisig setup again and its a bit confusing.

In one spot it says "never share your seed" & "never store it electronically" and then in one section when linking cosigners it allows you to use either the xpub (masterkey) or the seed.

%t1puzQW...

Question: If I gavea stranger all 6 public keys, what do they get access to?

A) Nothing
B) Read access on the wallet
C) Read/ Write access on wallet
D) Other?

If I remember write when I was making this wallet it was my_seed + 5*pubKeys ... so my incarnation of the wallet is different to yours... and I'd guess at least 1 seed is needed in order for me to have an ability to sign something as distinct from the rest of you.

@mix

I'm not sure. We should test this.

I speculate the following:

Having all the pubKeys means a person can generate a local wallet which will give them view access to the wallet.

They don't have is the privKeys to any of the pubKeys. I am not sure if they would would be able to brute force their way to the privKey or Seed with this info. @Nikolai posted a useful article which I have yet to digest:

%p3oAhdw...