http://cryptonite.info/wiki/index.php?title=Transaction_signing&feed=atom&action=historyTransaction signing - Revision history2024-03-29T10:09:53ZRevision history for this page on the wikiMediaWiki 1.23.1http://cryptonite.info/wiki/index.php?title=Transaction_signing&diff=66&oldid=prevAdmin: Fixed up stupid wording.2014-11-04T22:44:43Z<p>Fixed up stupid wording.</p>
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<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>__TOC__</div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>__TOC__</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>A signed [[Transactions | transaction]] is essentially some signed message very similar to a Bitcoin transaction, but without any scripting. It's a set of instructions for modifying the balance sheet (the [[account tree]]). To verify a withdrawal from any [[account]], the owner of the account must sign the transaction with the private key which corresponds to the account address. <del class="diffchange diffchange-inline">However if we're not careful, </del>such a <del class="diffchange diffchange-inline">signed message could </del>be <del class="diffchange diffchange-inline">used not just once</del>, <del class="diffchange diffchange-inline">but many times, and still </del>be <del class="diffchange diffchange-inline">valid. Luckily we can solve this</del>.</div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>A signed [[Transactions | transaction]] is essentially some signed message very similar to a Bitcoin transaction, but without any scripting. It's a set of instructions for modifying the balance sheet (the [[account tree]]). To verify a withdrawal from any [[account]], the owner of the account must sign the transaction with the private key which corresponds to the account address. <ins class="diffchange diffchange-inline">The [[mini-blockchain]] is designed in </ins>such a <ins class="diffchange diffchange-inline">way, that old transactions can </ins>be <ins class="diffchange diffchange-inline">forgotten</ins>, <ins class="diffchange diffchange-inline">so transaction signing must </ins>be <ins class="diffchange diffchange-inline">done in a way that prevents rebroadcasting of old forgotten transactions while not affecting the ability of the system to handle multiple concurrent transactions</ins>.  </div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>==Preventing Reuse of Signed Transactions==</div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>==Preventing Reuse of Signed Transactions==</div></td></tr>
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<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>* Nodes can incorporate transactions from abandoned branches into main chain if reorganization is smaller than N blocks.</div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>* Nodes can incorporate transactions from abandoned branches into main chain if reorganization is smaller than N blocks.</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>* It helps to make [[withdrawal limits]] work which makes double-spending considerably harder.</div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>* It helps to make [[withdrawal limits]] work which makes double-spending considerably harder.</div></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div><del style="font-weight: bold; text-decoration: none;"></del></div></td><td colspan="2"> </td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div><del style="font-weight: bold; text-decoration: none;">==Removing Transaction Malleability==</del></div></td><td colspan="2"> </td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>So, in order to make sure the same signed transaction isn't processed by the network more than once, the transaction must also contain a “lockheight” field. The transaction becomes invalid once the lockheight is outside the range of blocks which nodes are required to keep (lets call this the blocks “in view”), and same txid cannot be included twice in any of the blocks which are in view. This makes it impossible to use the same txid twice. However this solution requires that the txid is not malleable.</div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>So, in order to make sure the same signed transaction isn't processed by the network more than once, the transaction must also contain a “lockheight” field. The transaction becomes invalid once the lockheight is outside the range of blocks which nodes are required to keep (lets call this the blocks “in view”), and same txid cannot be included twice in any of the blocks which are in view. This makes it impossible to use the same txid twice. However this solution requires that the txid is not malleable.</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div><del class="diffchange diffchange-inline">There are several things which need to be considered when attempting to solve </del>transaction malleability, but <del class="diffchange diffchange-inline">most </del>importantly <del class="diffchange diffchange-inline">we can</del>'t include the signatures when hashing a transaction because signing the same data with the same key produces different signatures each time. The sender will sign the txid, but signing it many times in no way alters the txid, only the signatures. Thus attempting to alter the contents of the transaction will always change the txid and as a result invalidate the signature(s).</div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline">==Removing Transaction Malleability==</ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div> </div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins class="diffchange diffchange-inline">One of the reasons Cryptonite does not suffer from </ins>transaction malleability <ins class="diffchange diffchange-inline">is because it doesn't use scripting</ins>, but <ins class="diffchange diffchange-inline">more </ins>importantly <ins class="diffchange diffchange-inline">it doesn</ins>'t include the signatures when hashing a transaction because signing the same data with the same key produces different signatures each time. The sender will sign the txid, but signing it many times in no way alters the txid, only the signatures. Thus attempting to alter the contents of the transaction will always change the txid and as a result invalidate the signature(s).</div></td></tr>
</table>Adminhttp://cryptonite.info/wiki/index.php?title=Transaction_signing&diff=61&oldid=prevAdmin: fixed incorrect statement2014-07-31T06:14:40Z<p>fixed incorrect statement</p>
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<td colspan='2' style="background-color: white; color:black; text-align: center;">Revision as of 06:14, 31 July 2014</td>
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<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>==Removing Transaction Malleability==</div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>==Removing Transaction Malleability==</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'>−</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #ffe49c; vertical-align: top; white-space: pre-wrap;"><div>So, in order to make sure the same signed transaction isn't processed by the network more than once, the <del class="diffchange diffchange-inline">block header </del>must also contain a “lockheight” field. The transaction becomes invalid once the lockheight is outside the range of blocks which nodes are required to keep (lets call this the blocks “in view”), and same txid cannot be included twice in any of the blocks which are in view. This makes it impossible to use the same txid twice. However this solution requires that the txid is not malleable.</div></td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div>So, in order to make sure the same signed transaction isn't processed by the network more than once, the <ins class="diffchange diffchange-inline">transaction </ins>must also contain a “lockheight” field. The transaction becomes invalid once the lockheight is outside the range of blocks which nodes are required to keep (lets call this the blocks “in view”), and same txid cannot be included twice in any of the blocks which are in view. This makes it impossible to use the same txid twice. However this solution requires that the txid is not malleable.</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>There are several things which need to be considered when attempting to solve transaction malleability, but most importantly we can't include the signatures when hashing a transaction because signing the same data with the same key produces different signatures each time. The sender will sign the txid, but signing it many times in no way alters the txid, only the signatures. Thus attempting to alter the contents of the transaction will always change the txid and as a result invalidate the signature(s).</div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>There are several things which need to be considered when attempting to solve transaction malleability, but most importantly we can't include the signatures when hashing a transaction because signing the same data with the same key produces different signatures each time. The sender will sign the txid, but signing it many times in no way alters the txid, only the signatures. Thus attempting to alter the contents of the transaction will always change the txid and as a result invalidate the signature(s).</div></td></tr>
</table>Adminhttp://cryptonite.info/wiki/index.php?title=Transaction_signing&diff=40&oldid=prevAdmin: added table of contents2014-07-18T15:28:07Z<p>added table of contents</p>
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<td colspan='2' style="background-color: white; color:black; text-align: center;">Revision as of 15:28, 18 July 2014</td>
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<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;">__TOC__</ins></div></td></tr>
<tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="color:black; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #a3d3ff; vertical-align: top; white-space: pre-wrap;"><div><ins style="font-weight: bold; text-decoration: none;"></ins></div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>A signed [[Transactions | transaction]] is essentially some signed message very similar to a Bitcoin transaction, but without any scripting. It's a set of instructions for modifying the balance sheet (the [[account tree]]). To verify a withdrawal from any [[account]], the owner of the account must sign the transaction with the private key which corresponds to the account address. However if we're not careful, such a signed message could be used not just once, but many times, and still be valid. Luckily we can solve this.</div></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"><div>A signed [[Transactions | transaction]] is essentially some signed message very similar to a Bitcoin transaction, but without any scripting. It's a set of instructions for modifying the balance sheet (the [[account tree]]). To verify a withdrawal from any [[account]], the owner of the account must sign the transaction with the private key which corresponds to the account address. However if we're not careful, such a signed message could be used not just once, but many times, and still be valid. Luckily we can solve this.</div></td></tr>
<tr><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td><td class='diff-marker'> </td><td style="background-color: #f9f9f9; color: #333333; font-size: 88%; border-style: solid; border-width: 1px 1px 1px 4px; border-radius: 0.33em; border-color: #e6e6e6; vertical-align: top; white-space: pre-wrap;"></td></tr>
</table>Adminhttp://cryptonite.info/wiki/index.php?title=Transaction_signing&diff=31&oldid=prevAdmin: Added page to wiki2014-07-16T08:58:12Z<p>Added page to wiki</p>
<p><b>New page</b></p><div>A signed [[Transactions | transaction]] is essentially some signed message very similar to a Bitcoin transaction, but without any scripting. It's a set of instructions for modifying the balance sheet (the [[account tree]]). To verify a withdrawal from any [[account]], the owner of the account must sign the transaction with the private key which corresponds to the account address. However if we're not careful, such a signed message could be used not just once, but many times, and still be valid. Luckily we can solve this.<br />
<br />
==Preventing Reuse of Signed Transactions==<br />
<br />
A scheme with limited duplicate checking:<br />
* Lets define N to be less than minimum number of historical blocks every node is required to keep (see [[cycle time]]).<br />
* Creator of transaction puts latest block number inside txn and signs it. Lets call this block number K.<br />
* Network treats such transaction as valid if it is included in one of blocks from K+1 to K+N.<br />
* If the same transaction with the same signature was already included in one of past N blocks then it is rejected.<br />
<br />
This scheme has the following advantages:<br />
* Does not affect concurrent transaction generation.<br />
* Can be used to make time locked transactions ([[Cryptonite]] allows delay of no more than 5 blocks to prevent DoS attacks).<br />
* Nodes can incorporate transactions from abandoned branches into main chain if reorganization is smaller than N blocks.<br />
* It helps to make [[withdrawal limits]] work which makes double-spending considerably harder.<br />
<br />
==Removing Transaction Malleability==<br />
<br />
So, in order to make sure the same signed transaction isn't processed by the network more than once, the block header must also contain a “lockheight” field. The transaction becomes invalid once the lockheight is outside the range of blocks which nodes are required to keep (lets call this the blocks “in view”), and same txid cannot be included twice in any of the blocks which are in view. This makes it impossible to use the same txid twice. However this solution requires that the txid is not malleable.<br />
<br />
There are several things which need to be considered when attempting to solve transaction malleability, but most importantly we can't include the signatures when hashing a transaction because signing the same data with the same key produces different signatures each time. The sender will sign the txid, but signing it many times in no way alters the txid, only the signatures. Thus attempting to alter the contents of the transaction will always change the txid and as a result invalidate the signature(s).</div>Admin