<p>In Open-Transactions, both parties have a copy of the "last signed receipt" for any given transaction.</p>

<p>The user forms the receipt and signs it, and then the server countersigns it.</p>

<p>Therefore the server cannot forge your receipt because the server does not have your private key.</p>

<p>When an issuer issues his currency onto an OT server, the server will have a copy of the issuer's "last signed receipt," which includes the server ID and shows the current amount that has been issued.</p>

<p>So the server cannot falsely claim to have a certain currency issued on that server, because the server cannot forge the issuer's signature (in the same way that the server cannot falsify your own receipt, since the server cannot forge your signature.)</p>

<p>The other users cannot forge your signature, nor can they forge the server's signature, nor can they forge the issuer's signature, so they cannot falsely issue units of your currency.</p>

<p>Also, each "last signed receipt" includes the current balance. For example, "My current balance is 100 clams. I am withdrawing 10 clams, and my new balance will thus be 90 clams." This receipt also contains the server ID, as well as the asset type ID, and must be signed by the user before being countersigned by the server. Therefore this is also true for the issuer's last signed receipt, the same as for any other user.</p>

CC BY-SA 3.0
2013-08-21T06:47:00.857Z
2013-08-23T18:39:31.097Z
2013-08-23T18:39:31.097Z
Fellow Traveler
<p>"The public key of the issuer must be INSIDE the contract. (In the sample contracts, it’s the first key that appears.)"</p>

<ul>
<li><a href="https://github.com/FellowTraveler/Open-Transactions/wiki/FAQ" rel="nofollow">https://github.com/FellowTraveler/Open-Transactions/wiki/FAQ</a></li>
</ul>

<p>So a counterfeit issue would not have the right digital signature.</p>

CC BY-SA 3.0
2013-08-20T22:37:35.293Z
2013-08-20T22:37:35.293Z
Stephen Gornick
<p>if i see it correctly, there is a certain statical data within each existing cryptocurrency client, that is used to interact with the entire network. for example, you can't create bitcoin from air and add it to an existing bitcoin network. it will have to match the tree of cryptographical operations so far. there is original bitcoin paper out there and <a href="https://en.bitcoin.it/wiki/Weaknesses" rel="nofollow">https://en.bitcoin.it/wiki/Weaknesses</a>  to help you better understand the possible problems and issues of bitcoin network.</p>

CC BY-SA 3.0
2013-08-20T16:33:52.080Z
I see, but that's more related to a completely descentralized currency like bitcoin. If i create a centralized currency, it has to be possible somehow to create new "coins" out of thin air and issue them to the system. The question is: what would stop other people (besides the currency creator) from doing it?
Coiner
CC BY-SA 3.0
2013-08-20T16:42:07.970Z
oh, sorry I didn't knew this is mean to be a software "Open Transactions", i was thinking you were referring to bitcoin like nets.
kanojo
CC BY-SA 3.0
2013-08-20T15:12:52.460Z
2013-08-20T15:12:52.460Z
kanojo
<p>Say I create my own currency in Open Transactions, and begin trading it on OT with other users. What prevents some user from creating copies of my currency? I'm not sure its the same situation as double spending. I'm talking about someone who doesn't have any of my money simply creating it out of thin air and selling it to other people.</p>

<open-transactions>
How does Open Transactions handle counterfeiting of currencies?
Coiner
# How does Open Transactions handle counterfeiting of currencies?

(Asked by: username_0 on 2013-08-20)

Say I create my own currency in Open Transactions, and begin trading it on OT with other users. What prevents some user from creating copies of my currency? I'm not sure its the same situation as double spending. I'm talking about someone who doesn't have any of my money simply creating it out of thin air and selling it to other people.

**Tags:** open-transactions


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## 3 answers

### Answer by username_1 on 2013-08-21. Score: 1

In Open-Transactions, both parties have a copy of the "last signed receipt" for any given transaction.

The user forms the receipt and signs it, and then the server countersigns it.

Therefore the server cannot forge your receipt because the server does not have your private key.

When an issuer issues his currency onto an OT server, the server will have a copy of the issuer's "last signed receipt," which includes the server ID and shows the current amount that has been issued.

So the server cannot falsely claim to have a certain currency issued on that server, because the server cannot forge the issuer's signature (in the same way that the server cannot falsify your own receipt, since the server cannot forge your signature.)

The other users cannot forge your signature, nor can they forge the server's signature, nor can they forge the issuer's signature, so they cannot falsely issue units of your currency.

Also, each "last signed receipt" includes the current balance. For example, "My current balance is 100 clams. I am withdrawing 10 clams, and my new balance will thus be 90 clams." This receipt also contains the server ID, as well as the asset type ID, and must be signed by the user before being countersigned by the server. Therefore this is also true for the issuer's last signed receipt, the same as for any other user.


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### Answer by username_2 on 2013-08-20. Score: 0

"The public key of the issuer must be INSIDE the contract. (In the sample contracts, it’s the first key that appears.)"

* <https://github.com/username_1/Open-Transactions/wiki/FAQ>

So a counterfeit issue would not have the right digital signature.


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### Answer by username_3 on 2013-08-20. Score: -2

if i see it correctly, there is a certain statical data within each existing cryptocurrency client, that is used to interact with the entire network. for example, you can't create bitcoin from air and add it to an existing bitcoin network. it will have to match the tree of cryptographical operations so far. there is original bitcoin paper out there and <https://en.bitcoin.it/wiki/Weaknesses> to help you better understand the possible problems and issues of bitcoin network.

> **Comments:**
> **username_0**: I see, but that's more related to a completely descentralized currency like bitcoin. If i create a centralized currency, it has to be possible somehow to create new "coins" out of thin air and issue them to the system. The question is: what would stop other people (besides the currency creator) from doing it?  
> **username_3**: oh, sorry I didn't knew this is mean to be a software "Open Transactions", i was thinking you were referring to bitcoin like nets.  

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