<ul>
<li>A1B1: <a href="https://bitcoinarmory.com/using-offline-wallets-in-armory/" rel="nofollow">Assuming you've prepared in advance, there are some nice offline wallet options.</a></li>
<li><p>A1B2: This one's tricky. I'm going to assume that you have access to a computer before running off into the woods, or what have you. I'm also going to assume that you know exactly the amount and address in advance.   </p>

<ol>
<li><p>Generate the transaction and sign it, but don't broadcast it (can be done with Bitcoin Armory)</p></li>
<li><p>Print out the transaction</p></li>
<li>When you want to make the transaction, mail the transaction to your agent.</li>
</ol></li>
<li>A2B?: Easiest one. Just write down your private key and describe the transaction.</li>
<li>A3B?: Well, you're screwed, because the agent could just never make the transaction.</li>
</ul>

CC BY-SA 3.0
2013-03-28T19:00:52.423Z
Thanks! About A3, so they couldn't just send the funds to another address (not the intended recipient) if I sent them the transaction as in A1B2? And I'm assuming that's because of the signature.
Manish
CC BY-SA 3.0
2013-03-28T19:07:49.967Z
I suppose for A3 one option would be to build redundancy by having multiple agents, and multiple payments could be prevented by having only the exact amount available via that particular sender address (so only one of the transactions would go through).
Manish
CC BY-SA 3.0
2013-03-28T21:18:33.547Z
@Manish `"couldn't just send the funds to another address" "because of the signature"` Yep. `"multiple payments could be prevented"` As long as you hand the exact same TX to every agent, you don't need to.
Nick ODell
CC BY-SA 3.0
2013-03-29T00:24:21.310Z
Great answer, you beat me to it! A1B2 is probably the most secure option of these.
Colin Dean
CC BY-SA 3.0
2013-03-29T12:04:47.347Z
@NickODell "As long as you hand the exact same TX to every agent ..." Hmm, how does that work? A transaction says "Send N bitcoins from X address to Y address (signed by X)" so what keeps it from going through multiple times as long as there's funds in X?
Manish
CC BY-SA 3.0
2013-03-29T21:18:29.037Z
@NickODell Alright, I see my mistake. It's not "Send N bitcoins from X address to Y address (signed X)". Rather it's (roughly) "Send N bitcoins from output X to output Y,Y' (signed X)" where Y' is the change and X is empty after it's done.
Manish
CC BY-SA 3.0
2013-03-28T17:52:26.347Z
2013-03-28T17:52:26.347Z
Nick ODell
<p>Suppose I'm stuck in the middle of nowhere with no internet access and I want to make a payment to a certain Bitcoin address.</p>

<p><strong>Is it possible to do a transfer via postal mail, and if so what information would I need to send?</strong></p>

<p>Assume the following:</p>

<ol>
<li>I have both the recipient's Bitcoin address and my (the sender's) own private key(s) memorized or written down on a piece of paper.</li>
<li>The person who receives the mail (my agent) has access to the Bitcoin network and will act on my behalf.</li>
<li>The mail is delivered securely (i.e. no chance of theft)</li>
</ol>

<p>What information would I need to send in the mail?</p>

<p>Consider the following possibilities:</p>

<ul>
<li><p>A)  Trust</p>

<ol>
<li>I trust my agent to do the transfer to the given address (e.g. the agent is the recipient), but I can't trust my agent with my private key(s)</li>
<li>I trust my agent with all my information (private keys and all)</li>
<li>I do not trust my agent at all</li>
</ol></li>
<li><p>B)  Access to a computer</p>

<ol>
<li>I have access to a computer, so I can run any program/scripts that may be required for generating any signatures</li>
<li>I don't have access to a computer (and I'm not Rain Man)</li>
</ol></li>
</ul>

CC BY-SA 3.0
2013-03-28T00:44:28.950Z
"I have access to a computer" "I don't have access to a computer" Huh?
Nick ODell
CC BY-SA 3.0
2013-03-28T01:13:44.957Z
@NickODell, Manish is asking us to consider both those possibilities
Highly Irregular
CC BY-SA 3.0
2013-03-28T01:19:49.900Z
@NickODell That's right, what are my options if (1) I have access to a computer, and what if (2) I don't.
Manish
CC BY-SA 3.0
2013-03-28T03:26:57.290Z
If no one else answers this by the time I have time tomorrow, I'm all over this.
Colin Dean
<transactions><offline>
Can a transfer be done over postal mail?
Manish
# Can a transfer be done over postal mail?

(Asked by: username_0 on 2013-03-28)

Suppose I'm stuck in the middle of nowhere with no internet access and I want to make a payment to a certain Bitcoin address.

**Is it possible to do a transfer via postal mail, and if so what information would I need to send?**

Assume the following:

1. I have both the recipient's Bitcoin address and my (the sender's) own private key(s) memorized or written down on a piece of paper.
2. The person who receives the mail (my agent) has access to the Bitcoin network and will act on my behalf.
3. The mail is delivered securely (i.e. no chance of theft)

What information would I need to send in the mail?

Consider the following possibilities:

* A) Trust

  1. I trust my agent to do the transfer to the given address (e.g. the agent is the recipient), but I can't trust my agent with my private key(s)
  2. I trust my agent with all my information (private keys and all)
  3. I do not trust my agent at all
* B) Access to a computer

  1. I have access to a computer, so I can run any program/scripts that may be required for generating any signatures
  2. I don't have access to a computer (and I'm not Rain Man)

**Tags:** transactions, offline

> **Comments:**
> **username_1**: "I have access to a computer" "I don't have access to a computer" Huh?  
> **username_2**: @username_1, username_0 is asking us to consider both those possibilities  
> **username_0**: @username_1 That's right, what are my options if (1) I have access to a computer, and what if (2) I don't.  
> **username_3**: If no one else answers this by the time I have time tomorrow, I'm all over this.  

---

## 1 answers

### Answer by username_1 on 2013-03-28. Score: 3 | Accepted answer

* A1B1: [Assuming you've prepared in advance, there are some nice offline wallet options.](https://bitcoinarmory.com/using-offline-wallets-in-armory/)
* A1B2: This one's tricky. I'm going to assume that you have access to a computer before running off into the woods, or what have you. I'm also going to assume that you know exactly the amount and address in advance.

  1. Generate the transaction and sign it, but don't broadcast it (can be done with Bitcoin Armory)
  2. Print out the transaction
  3. When you want to make the transaction, mail the transaction to your agent.
* A2B?: Easiest one. Just write down your private key and describe the transaction.
* A3B?: Well, you're screwed, because the agent could just never make the transaction.

> **Comments:**
> **username_0**: Thanks! About A3, so they couldn't just send the funds to another address (not the intended recipient) if I sent them the transaction as in A1B2? And I'm assuming that's because of the signature.  
> **username_0**: I suppose for A3 one option would be to build redundancy by having multiple agents, and multiple payments could be prevented by having only the exact amount available via that particular sender address (so only one of the transactions would go through).  
> **username_1**: @username_0 `"couldn't just send the funds to another address" "because of the signature"` Yep. `"multiple payments could be prevented"` As long as you hand the exact same TX to every agent, you don't need to.  
> **username_3**: Great answer, you beat me to it! A1B2 is probably the most secure option of these.  
> **username_0**: @username_1 "As long as you hand the exact same TX to every agent ..." Hmm, how does that work? A transaction says "Send N bitcoins from X address to Y address (signed by X)" so what keeps it from going through multiple times as long as there's funds in X?  
> **username_0**: @username_1 Alright, I see my mistake. It's not "Send N bitcoins from X address to Y address (signed X)". Rather it's (roughly) "Send N bitcoins from output X to output Y,Y' (signed X)" where Y' is the change and X is empty after it's done.  

---

