<oembed><type>rich</type><version>1.0</version><title>Lloyd Fournier [ARCHIVE] wrote</title><author_name>Lloyd Fournier [ARCHIVE] (npub1kh…y05yp)</author_name><author_url>https://yabu.me/npub1khlhcuz0jrjwa0ayznq2q9agg4zvxfvx5x7jljrvwnpfzngrcf0q7y05yp</author_url><provider_name>njump</provider_name><provider_url>https://yabu.me</provider_url><html>📅 Original date posted:2021-04-04&#xA;📝 Original message:On Tue, 16 Mar 2021 at 11:25, David A. Harding via bitcoin-dev &lt;&#xA;bitcoin-dev at lists.linuxfoundation.org&gt; wrote:&#xA;&#xA;&gt;&#xA;&gt; I curious about whether anyone informed about ECC and QC&#xA;&gt; knows how to create output scripts with lower difficulty that could be&#xA;&gt; used to measure the progress of QC-based EC key cracking.  E.g.,&#xA;&gt; NUMS-based ECDSA- or taproot-compatible scripts with a security strength&#xA;&gt; equivalent to 80, 96, and 112 bit security.&#xA;&#xA;&#xA;Hi Dave,&#xA;&#xA;This is actually relatively easy if you are willing to use a trusted setup.&#xA;The trusted party takes a secp256k1 secret key and verifiably encrypt it&#xA;under a NUMS public key from the weaker group. Therefore if you can crack&#xA;the weaker group&#39;s public key you get the secp256k1 secret key.&#xA;Camenisch-Damgard[1] cut-and-choose verifiable encryption works here.&#xA;People then pay the secp256k1 public key funds to create the bounty. As&#xA;long as the trusted party deletes the secret key afterwards the scheme is&#xA;secure.&#xA;&#xA;Splitting the trusted setup among several parties where only one of them&#xA;needs to be honest looks doable but would take some engineering and&#xA;analysis work.&#xA;&#xA;[1] https://link.springer.com/content/pdf/10.1007/3-540-44448-3_25.pdf&#xA;&#xA;Cheers,&#xA;&#xA;LL&#xA;-------------- next part --------------&#xA;An HTML attachment was scrubbed...&#xA;URL: &lt;http://lists.linuxfoundation.org/pipermail/bitcoin-dev/attachments/20210405/599aee9f/attachment-0001.html&gt;</html></oembed>