[ESHOP launched] Trezor: Bitcoin hardware wallet

[BurtW]

The Trezor calculates the change address so it knows it is correct so it does not need to bother you to veryify something that it knows is correct and cannot be faked, since everything happens inside the Trezor.

Stop
It can be calculated based by blockchain.
Trezor doesn't know the blockchain. So it cannot calculate it.
Only computer with opened site MyTrezor.com can help because only computer knows which addresses are not used.

You are right, I got off on a little bit of a tangent and I am sorry.  Try this:

All of the change addresses can be determined from xpriv which is derived from the seed.
The seed, xpriv, all the receive addresses, all the change addresses are or can be calculated inside the Trezor.

Sure, the change address can also be calculated from the xpub on the myTrezor web site (or any other wallet that supports Trezor).

So, since myTrezor calculates the change address from xpub and Trezor calculates the same change address from xpriv the Trezor can verify that the myWallet (or any other wallet) calculated the same change address.  If the two change addresses do not match the Trezor can simply refuse to sign the transaction and reject it.

Same result:  we don't need to be bothered to verify the change address because the Trezor can verify it.

BTW I went back and fixed my previous post.

[Perlover]

All of the change addresses are determined from xpriv which is derived from the seed.
The seed, xpriv, all the receive addresses, all the change addresses can all calculated inside the Trezor.

Sure, the change address can also be calculated from the xpub on the myTrezor web site (or any other wallet that supports Trezor).

So, since myTrezor calculates the change address from xpub and Trezor calculates the same change address from xpriv the Trezor can verify that the myWallet (or any other wallet) calculated the same change address.  If the two change addresses do not match the Trezor can simply refuse to sign the transaction and reject it.

Same result:  we don't need to be bothered to verify the change address because the Trezor can verify it.

BTW I went back and fixed my previous post.

If you will read my post about this, you will see that i mean it.
And what mean "Trezor calculates the same change address"?
It should calculates with some tip from computer. Amount fo change addresses is inifinity. How the Trezor calculate "same address"? Trezor doesn't know blockchain and doesn't know which addresses are used and which are not...
I wrote about path of BIP32/BIP44 tipped from computer.

But i am not sure that this realized same way.

[Perlover]

Sorry if this sounds mean but I don't think you understand how bitcoin works. I can give you some great links if you like that will help you understand on a more technical level.

P.S. Are you spam bot?

[sipak]

Hi,

I noticed the strange thing.

The Trezor is device for signing all outputs and all outputs should be showed to me in screen and values of each output.
Is it correct?

But i noticed that when i send some money to addresses A, B, C (i did the transaction for 10 addresses) there was 11th output - it's OK, one address is change from my wallet.

BUT! The 11th address is not showed by Trezor (or 1st) - this is the change adress. So one address slips away from my eye. It's very strange.
How the Trezor decides that one address should not be showed (and value too!) to me when i sign the transaction?

I understood that it made may be for easy using. But i would know the algorithm for this decision.
May be there security hole? Can hacker tell to the Trezor that one X address from faked transaction is change address and after this the Trezor could not show to me this address and value in Trezor's screen?

I can imagine that the Trezor could get the change address as path of BIP32/BIP44 and inside itself can recalculate the address and after it decides that this address is a really my own change address and doesn't show one me and value for it. But i am not sure that this done same way. If there in protocol only bit for address (change/not_change) - it will be security hole for trojan.

I think the Trezor should show all outputs and value of each output included a change address. A change address could be showed with remark 'Your Change' or other way. Otherwise, the thought creeps in that the algorithm has a loophole.

How do you think?
And what does Stick or Slush think about this? I don't want to ask this to through ticket system because the Trezor project should be discussed publicly.

When you are composing transaction, you see on the right all output addresses. The change address is represented by path and it is sent by myTrezor wallet to the Trezor device as this path. This is why Trezor doesn't show anything, because it knows, it generates that address itself from the seed. You can pregenerate this internal address by using account xpub and the shown path on bip32.org. If you give this address to Trezor explicitly and fill in the right change ammount, you will have to confirm it on the screen as with every other external ouput. Trezor doesn't recognize it as internal address when it is not sent as a path to it. The same thing is when you send bitcoins bitween accounts in the same Trezor, you have to confirm them, since Trezor doesn't know they are internal with respect to the seed as well.

Anyway, it might be good if user could somehow choose if the change address will be shown explicitly by clicking something like "Send Advanced". In this scenario, Trezor would also show something like "Confirm sending change to an internal address 3/1/18 = 1ase4er4wFASDFdasdfdfdf..."

[blossbloss]

So in that photo a ways back..the classics you showed were black, is there any chance of getting those instead of white?

There might be good news next week for you :-) *wink*

very curious if stick's wink is still accurate
any updates on the wink? 

[Perlover]

When you are composing transaction, you see on the right all output addresses. The change address is represented by path and it is sent by myTrezor wallet to the Trezor device as this path. This is why Trezor doesn't show anything, because it knows, it generates that address itself from the seed.

If the Trezor works with same algorithm - it's fine.
If the developer could confirm it ("The change address is represented by path and it is sent by myTrezor wallet to the Trezor device as this path")
But as i wrote for other people can be strange that transaction has 2 outputs and they saw only one address & value when they signed the transaction.
Yes, i see, it's better (not show change address) for easy using of the Trezor. May be it should be as option in software which comunicates with the Trezor

> You can pregenerate this internal address by using account xpub and the shown path on bip32.org.
> If you give this address to Trezor explicitly and fill in the right change ammount,
> you will have to confirm it on the screen as with every other external ouput. Trezor doesn't recognize it as internal address when it is not sent as a path to it.

It's interesting test. But it not gaurantee that the path change address algorithm there works.
There may be there other alogorithm - change address are marked in program interface by special bit for example. If you enter address manually - there no bit, if computer calculate change address based on xpub - there is bit. But it will be bad algorithm.

I hope that change address is calculated inside Trezor based on sent BIP44 path of address.

P.S.
> When you are composing transaction, you see on the right all output addresses.
> The change address is represented by path and it is sent by myTrezor wallet to the Trezor device as this path.
> This is why Trezor doesn't show anything, because it knows, it generates that address itself from the seed.

Yes, i did other transaction and i see that there change address is presented as BIP44 path. I think now that the Trezor gets from a computer not a Bitcoin change address but the only BIP44's path and the Trezor calculates the address inside...

P.P.S. I want thank the Trezor team for nice device !

[klokan]

When you are composing transaction, you see on the right all output addresses. The change address is represented by path and it is sent by myTrezor wallet to the Trezor device as this path. This is why Trezor doesn't show anything, because it knows, it generates that address itself from the seed.

If the Trezor works with same algorithm - it's fine.
If the developer could confirm it ("The change address is represented by path and it is sent by myTrezor wallet to the Trezor device as this path")
But as i wrote for other people can be strange that transaction has 2 outputs and they saw only one address & value when they signed the transaction.
Yes, i see, it's better (not show change address) for easy using of the Trezor. May be it should be as option in software which comunicates with the Trezor

> You can pregenerate this internal address by using account xpub and the shown path on bip32.org.
> If you give this address to Trezor explicitly and fill in the right change ammount,
> you will have to confirm it on the screen as with every other external ouput. Trezor doesn't recognize it as internal address when it is not sent as a path to it.

It's interesting test. But it not gaurantee that the path change address algorithm there works.
There may be there other alogorithm - change address are marked in program interface by special bit for example. If you enter address manually - there no bit, if computer calculate change address based on xpub - there is bit. But it will be bad algorithm.

I hope that change address is calculated inside Trezor based on sent BIP44 path of address.

You find it strange, because you were raised in environment, where it was necessary to check where "the rest of BTC" go. But this is in fact unnecessary. You have a wallet that has many addresses. In the scenario where you are spending to 10 output addresses, what SHOULD happen is that you should confirm those 10 addresses and the rest of BTC go back to you. That's it. The change depends on the inputs chosen by the algorithm. Imagine you have 1 BTC on 5 addresses 0.2BTC each. If you are spending 0.5BTC, then 3 inputs are used and the change is 0.1BTC. It may be even more confusing to a unexperinced user expecting change to be 0.5BTC. Since it can be arbitrary number going to your own address there is no point confirming it as many people already told you.

All addresses are (edit:)BIP44 compliant so it is really the same algorithm used on the web wallet and Trezor. There is no question about it.

[keithers]

are there any videos, or "How To" guides that show how to use trezor with Electrum or with multibit?   I have been using the trezor web wallet, but would like to try it with electrum or multibit (and I have never used either of those clients before).    thanks guys...

[Anon136]

Sorry if this sounds mean but I don't think you understand how bitcoin works. I can give you some great links if you like that will help you understand on a more technical level.

P.S. Are you spam bot?

Lol. No I'm not a spam bot. I have >4200 posts. I never would have lasted that long spamming.

[Valzador]

If you have less than $1000 in BTC then this product may not be for you.  But for someone who has thousands, tens of thousands, hundreds of thousands, etc. then this is a great product.  I love this little thing.  I have 5 of them and will be ordering a couple more for Christmas gifts for people I know that have BTC holdings.  It is the second best thing I have ever purchased with BTC, the best one being a case of Girl Scout thin mint cookies.

Is it safe having 2 or more trezors running with the same seed?

[oyhmxh]

Looks pretty awesome but a little expensive

[binford]

I would love to buy one but 119 bucks? ... expensive for the newbies.

if you're confident to manage your crypto currency safely, buy that instead of the hardware wallet and buy one in future (hopefully for less than it costs now; hint spend later a fraction of bitcoins that you buy today with the same amount of $ or eur that you spend today)

if this thing would be around years ago it would already be cheaper ; )
and probably thousands of coins would not have been stolen in the meantime

[slush]

When you are composing transaction, you see on the right all output addresses. The change address is represented by path and it is sent by myTrezor wallet to the Trezor device as this path. This is why Trezor doesn't show anything, because it knows, it generates that address itself from the seed.

If the Trezor works with same algorithm - it's fine.

If the developer could confirm it ("The change address is represented by path and it is sent by myTrezor wallet to the Trezor device as this path")

Confirm. Trezor does not display those outputs which are provably going back to Trezor.

But as i wrote for other people can be strange that transaction has 2 outputs and they saw only one address & value when they signed the transaction.

No, it is strange to *you*, because you actually do expect that there's something called "change address". Btw displaying change address to common user has no sense, because user himself don't know if given change address is correct or not...

[Sophokles]

Will there be a version with metal casing anytime soon? Great product, anyway!

[hbee]

Is there something going on with mytrezor.com? I cannot access my balance, it just gets stuck in "Loading..." with those three bars. I've already reinstalled the plugin and tried different browsers.

[devthedev]

Is there something going on with mytrezor.com? I cannot access my balance, it just gets stuck in "Loading..." with those three bars. I've already reinstalled the plugin and tried different browsers.

I'm having the same issue...

A resolution as soon as possible would be appreciated.

[BurtW]

Is there something going on with mytrezor.com? I cannot access my balance, it just gets stuck in "Loading..." with those three bars. I've already reinstalled the plugin and tried different browsers.

I'm having the same issue...

A resolution as soon as possible would be appreciated.

Yes it is down.  I reported it to them through their support email address:  support@bitcointrezor.com

They do not hang out here that much so if you ever have problems use their support email address.

(but they probably already know it is down)

[gweedo]

Why don't you guys use all the other wallets that support trezor Isn't that you all told me to do...

[stick]

Should be OK now.

[devthedev]

Should be OK now.

It seems to be working again.
Thanks!