<p>As a few have suggested, Green Addresses '1.0' had issues.</p>

<p>Some improvements that were suggested as early as in 2011 which you can see implemented in <a href="https://greenaddress.it" rel="nofollow">GreenAddress</a> prevents users from double spending transactions via multisignature thus allowing zero confirmation for third parties that trust the GreenAddress provider, yet preventing users from risking their funds in someone else's online wallet.</p>

<p>See also this blog post about <a href="http://blog.greenaddress.it/2014/04/18/when-you-can-and-cant-rely-on-0-confirmations" rel="nofollow">0 confirmations</a> or the <a href="http://blog.greenaddress.it/2014/04/05/firstpost-updates/" rel="nofollow">design/'whitepaper'</a></p>

CC BY-SA 3.0
2014-10-13T07:51:13.117Z
Why does the wiki say that green addresses are not advised? https://en.bitcoin.it/wiki/Green_address
B T
CC BY-SA 3.0
2018-03-27T06:17:49.540Z
The wallet linked here has serious UI issues, beware: http://mhluska.com/blog/why-you-should-avoid-green-address-bitcoin-wallet
Maros
CC BY-SA 3.0
2014-04-26T13:19:34.243Z
2014-04-26T13:19:34.243Z
Lawrence Nahum
<p>The green address is a third party trust trick and can help resolve most problems related to the need to wait for confirmations (slow transactions).</p>
<p>To make it very simple :</p>
<p>Service A publishes its green address, service B decides to trust service A.</p>
<p>When someone send bitcoins from service A to service B, he will send from the service A green address.</p>
<p>The service B knows he can trust the service A, he knows A won't double spend, so B can credit the sent bitcoins immediately, without waiting for confirmations ( or waiting for just one confirmation, which is probably wiser ).</p>
<p>This is mostly useful for transferring bitcoins b2b (business to business), typically it would help making arbitrage easier and faster between 2 bitcoin exchanges, if both decide to trust each other's green address.</p>
<p>This can also be useful to allow for POS (Point of sales) with instant transactions if the POS can trust the green address of your bitcoin bank (or online wallet)</p>
<p>As an individual, I could also negotiate with my local supermarket to trust my green address (providing them my IRL address, ID number and more if needed).  Once they decide to trust my green address, I can pay immediately with bitcoins at my local supermarket (they trust me and won't need to wait for confirmations).</p>
<p>The green address is just a bitcoin address, but it's a &quot;from&quot; address people decide to trust and accept transactions from this address without waiting for confirmations.</p>
<p>Possible drawbacks are :</p>
<ul>
<li><p>Less anonymity, or even no anonimity at all ( always using the same public from address), which is not a problem for a business, and its even great for public accounting/auditing ( yes bitcoin can also help fighting corruption ! )</p>
</li>
<li><p>Blockchain spam (more transactions for the bitcoin network), which is a good thing if the blockchain can scale.</p>
</li>
<li><p>Encourages people to use trusted wallet providers (some kind of bitcoin banks). Here too, this have good and bad sides.</p>
</li>
<li><p>It's not enough to create a green address, you still need to be trusted so that your green address is useful</p>
</li>
<li><p>For now, afaik, only <a href="http://mtgox.com/" rel="nofollow noreferrer">mtgox.com</a>, <a href="http://btcpak.com/" rel="nofollow noreferrer">btcpak.com</a> and <a href="http://instawallet.org/" rel="nofollow noreferrer">instawallet.org</a> support the idea.  To be useful, green address system needs to be widely adopted by bitcoin pools, exchanges, online wallets, businesses, etc.</p>
<p>See also <a href="https://en.bitcoin.it/wiki/Green_address" rel="nofollow noreferrer">https://en.bitcoin.it/wiki/Green_address</a>
( edit 11 years ago, october 2020 , this reference is no more very relevant, some people completely rewrote the wiki page years later,for obscure reasons . . . they even replaced the first line with a blockstream ad . . . but you can still go and check the earliest versions of this page, around 2011-2012 , by clicking the &quot;history&quot; tab of the wiki page )</p>
</li>
</ul>

CC BY-SA 4.0
2018-11-10T18:14:50.913Z
well explained!
Vijay Chavda
CC BY-SA 3.0
2011-10-25T12:33:15.497Z
Encouraging people to use eWallets might not be bad, if the eWallet is set up so it cannot still your money. See for example https://bitcointalk.org/index.php?topic=49689.msg591574#msg591574 and the following discussion.
Meni Rosenfeld
CC BY-SA 3.0
2011-10-25T13:08:42.387Z
agreed ! I also think people will need to use eWallets anyway when the blockchain will be 1GB size and more. the only thing is that we need serious, secure, trusted eWallet providers . I added this to the possible drawbacks only because many people in the bitcoin world are hating centralization . . . and there have been a big scandal with an anonymous eWallet service / mybitcoin affair, but yes, secure and trusted eWallets are needed for sure !
neofutur
CC BY-SA 3.0
2011-10-25T14:07:11.087Z
@MeniRosenfeld.  eWallets where the operator isn't in control of your balance by definition can't be greenaddresses.  So you can either have decentralized eWallets or "green address" eWallets.  You can't have both at the same time.
DeathAndTaxes
CC BY-SA 3.0
2011-10-25T15:55:32.890Z
@theUnhandledException - Not so. Read the link. The point is that sending coins requires signatures by both the eWallet and the client, so the client can't double spend and the eWallet can't steal the coins. What's novel about the suggestion (with my improvement) is precisely that it does allow you to have both.
Meni Rosenfeld
CC BY-SA 3.0
2011-10-25T15:56:23.060Z
@neofutur - the size of the blockchain doesn't necessitate an eWallet, only a lightweight client (which is better for availability).
Meni Rosenfeld
CC BY-SA 3.0
2011-10-25T16:00:26.003Z
I gave the wrong link (to a specific not so important comment in the thread), what I meant is https://bitcointalk.org/index.php?topic=49689.
Meni Rosenfeld
CC BY-SA 3.0
2012-03-02T04:23:36.507Z
@MeniRosenfeld the size of the blockchain is already more than 1 GB : ls -alh .bitcoin/blk* : .bitcoin/blk0001.dat-> 1011M ;  .bitcoin/blkindex.dat 384M . total more than 1 GB, its already too big for my small eepc, raspberrypi or phone, people not having 2 GB free diskspace cant use bitcoin until we have 1- a client able to use a blockchain provider 2- a trusted blockchain provider . personally I d already be ok to pay a ( really trusted ) blockchain provider 1 btc/year to save my diskspace
neofutur
CC BY-SA 3.0
2012-03-02T04:32:31.250Z
"a client able to use a blockchain provider" is probably what you called a "lightweight client", but until now and afaik this lightweight client is not existing, and there are no blockchain provider the lightweight client could use, and the blockchain being already more than 1 GB, my only option is to use a online wallet . . . I do it myself, using ssh and having the wallet on a dedicated sserver of mine.
neofutur
CC BY-SA 3.0
2012-03-02T06:16:10.503Z
@neofutur: Yes, a lightweight client is one which does not store the entire blockchain. I think some form of it exists already. There are several variants - one variant stores only private keys (and puts significant trust on providers to confirm transactions. StrongCoin et al are basically web-based clients of this type), another stores block headers and relevant Merkle branches to have more control over confirmation. Block headers are about 20MB now and only scale linearly with time, not with the number of transactions on the network.
Meni Rosenfeld
CC BY-SA 4.0
2011-10-25T12:01:12.783Z
2020-10-23T21:15:01.527Z
2020-10-23T21:15:01.527Z
neofutur
<p>What are Green Addresses? Is it true that they can solve the "confirmation delay" problem, and how does that work? Are there any drawbacks?</p>

<address><confirmations><green-address>
What are Green Addresses?
Thilo
# What are Green Addresses?

(Asked by: username_0 on 2011-10-25)

What are Green Addresses? Is it true that they can solve the "confirmation delay" problem, and how does that work? Are there any drawbacks?

**Tags:** address, confirmations, green-address


---

## 2 answers

### Answer by username_4 on 2011-10-25. Score: 41 | Accepted answer

The green address is a third party trust trick and can help resolve most problems related to the need to wait for confirmations (slow transactions).

To make it very simple :

Service A publishes its green address, service B decides to trust service A.

When someone send bitcoins from service A to service B, he will send from the service A green address.

The service B knows he can trust the service A, he knows A won't double spend, so B can credit the sent bitcoins immediately, without waiting for confirmations ( or waiting for just one confirmation, which is probably wiser ).

This is mostly useful for transferring bitcoins b2b (business to business), typically it would help making arbitrage easier and faster between 2 bitcoin exchanges, if both decide to trust each other's green address.

This can also be useful to allow for POS (Point of sales) with instant transactions if the POS can trust the green address of your bitcoin bank (or online wallet)

As an individual, I could also negotiate with my local supermarket to trust my green address (providing them my IRL address, ID number and more if needed). Once they decide to trust my green address, I can pay immediately with bitcoins at my local supermarket (they trust me and won't need to wait for confirmations).

The green address is just a bitcoin address, but it's a "from" address people decide to trust and accept transactions from this address without waiting for confirmations.

Possible drawbacks are :

* Less anonymity, or even no anonimity at all ( always using the same public from address), which is not a problem for a business, and its even great for public accounting/auditing ( yes bitcoin can also help fighting corruption ! )
* Blockchain spam (more transactions for the bitcoin network), which is a good thing if the blockchain can scale.
* Encourages people to use trusted wallet providers (some kind of bitcoin banks). Here too, this have good and bad sides.
* It's not enough to create a green address, you still need to be trusted so that your green address is useful
* For now, afaik, only [mtgox.com](http://mtgox.com/), [btcpak.com](http://btcpak.com/) and [instawallet.org](http://instawallet.org/) support the idea. To be useful, green address system needs to be widely adopted by bitcoin pools, exchanges, online wallets, businesses, etc.

  See also <https://en.bitcoin.it/wiki/Green_address>
  ( edit 11 years ago, october 2020 , this reference is no more very relevant, some people completely rewrote the wiki page years later,for obscure reasons . . . they even replaced the first line with a blockstream ad . . . but you can still go and check the earliest versions of this page, around 2011-2012 , by clicking the "history" tab of the wiki page )

> **Comments:**
> **username_6**: Encouraging people to use eWallets might not be bad, if the eWallet is set up so it cannot still your money. See for example https://bitcointalk.org/index.php?topic=49689.msg591574#msg591574 and the following discussion.  
> **username_4**: agreed ! I also think people will need to use eWallets anyway when the blockchain will be 1GB size and more. the only thing is that we need serious, secure, trusted eWallet providers . I added this to the possible drawbacks only because many people in the bitcoin world are hating centralization . . . and there have been a big scandal with an anonymous eWallet service / mybitcoin affair, but yes, secure and trusted eWallets are needed for sure !  
> **username_7**: @username_6.  eWallets where the operator isn't in control of your balance by definition can't be greenaddresses.  So you can either have decentralized eWallets or "green address" eWallets.  You can't have both at the same time.  
> **username_6**: @theUnhandledException - Not so. Read the link. The point is that sending coins requires signatures by both the eWallet and the client, so the client can't double spend and the eWallet can't steal the coins. What's novel about the suggestion (with my improvement) is precisely that it does allow you to have both.  
> **username_6**: @username_4 - the size of the blockchain doesn't necessitate an eWallet, only a lightweight client (which is better for availability).  
> **username_6**: I gave the wrong link (to a specific not so important comment in the thread), what I meant is https://bitcointalk.org/index.php?topic=49689.  
> **username_4**: @username_6 the size of the blockchain is already more than 1 GB : ls -alh .bitcoin/blk* : .bitcoin/blk0001.dat-> 1011M ;  .bitcoin/blkindex.dat 384M . total more than 1 GB, its already too big for my small eepc, raspberrypi or phone, people not having 2 GB free diskspace cant use bitcoin until we have 1- a client able to use a blockchain provider 2- a trusted blockchain provider . personally I d already be ok to pay a ( really trusted ) blockchain provider 1 btc/year to save my diskspace  
> **username_4**: "a client able to use a blockchain provider" is probably what you called a "lightweight client", but until now and afaik this lightweight client is not existing, and there are no blockchain provider the lightweight client could use, and the blockchain being already more than 1 GB, my only option is to use a online wallet . . . I do it myself, using ssh and having the wallet on a dedicated sserver of mine.  
> **username_6**: @username_4: Yes, a lightweight client is one which does not store the entire blockchain. I think some form of it exists already. There are several variants - one variant stores only private keys (and puts significant trust on providers to confirm transactions. StrongCoin et al are basically web-based clients of this type), another stores block headers and relevant Merkle branches to have more control over confirmation. Block headers are about 20MB now and only scale linearly with time, not with the number of transactions on the network.  
> **username_5**: well explained!  

---

### Answer by username_1 on 2014-04-26. Score: 3

As a few have suggested, Green Addresses '1.0' had issues.

Some improvements that were suggested as early as in 2011 which you can see implemented in [GreenAddress](https://greenaddress.it) prevents users from double spending transactions via multisignature thus allowing zero confirmation for third parties that trust the GreenAddress provider, yet preventing users from risking their funds in someone else's online wallet.

See also this blog post about [0 confirmations](http://blog.greenaddress.it/2014/04/18/when-you-can-and-cant-rely-on-0-confirmations) or the [design/'whitepaper'](http://blog.greenaddress.it/2014/04/05/firstpost-updates/)

> **Comments:**
> **username_2**: Why does the wiki say that green addresses are not advised? https://en.bitcoin.it/wiki/Green_address  
> **username_3**: The wallet linked here has serious UI issues, beware: http://mhluska.com/blog/why-you-should-avoid-green-address-bitcoin-wallet  

---

