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@AdamISZ
AdamISZ / SNICKER_BIP_draft.mediawiki
Last active April 3, 2023 20:09
SNICKER BIP draft 





  BIP: ??
  Layer: Applications
  Title: SNICKER - Simple Non-Interactive Coinjoin with Keys for Encryption Reused
  Author&#58; Adam Gibson <AdamISZ@protonmail.com>
  Comments&#45;Summary&#58; No comments yet.
  Comments&#45;URI&#58; &#45;
  Status&#58; Proposed
  Type&#58; Informational
  Created&#58; &#45;




  


  




    


          
    

      

        
        

          

              @AdamISZ
          

          

            
                AdamISZ
                / P2EP-for-JM.md
            
            

              Created
              December 27, 2018 18:48
            

              
                Basic payjoin/p2ep protocol for Joinmarket wallets
              
          

        

      

        

  

      

    
Described here is a variant of what has previously been published
under the name "P2EP" or Pay-to-endpoint, in which A pays B but B contributes utxos, i.e. it's a coinjoin-payment.


I'm using the term "payjoin" here to refer to using that idea, but not including a URI/endpoint specific to B, and
not allowing (as a merchant would) arbitrary payments, which opens up certain problems around snooping attackers
(more on this below).
So payjoin just means "A pays B but B actively participates and passes across utxos as extra inputs".


I'll defer a more features-focused and non-tech friendly description of what this means to a later blogpost.



  


  




    


          
    

      

        
        

          

              @Glorfindel83
          

          

            
                Glorfindel83
                / broken-image-repairer.md
            
            

              Last active
              August 19, 2023 14:08
            

              
                Broken Image Repairer
              
          

        

      

        

  

      

    
Broken Image Repairer


What is the problem?


A long time ago, it was possible to inline images from all kinds of external sources. Since the switch from HTTP to HTTPS, this is no longer possible; only HTTPS sources are allowed. This leads to ugly blurbs like




alt text http://example.com/image.png




instead of a nicely formatted page with images. Sometimes, the links don't even work anymore, even with HTTPS images, which will show like this:  ... Luckily, we have the Wayback Machine which is able to rescue some of the lost images. Since a picture often says more than a thousand words, it's important to bring back the post into its original state; important enough to justify the occasional bump of an old post (see below).



  


  




    


          
    

      

        
        

          

              @sipa
          

          

            
                sipa
                / covert_ecdh.md
            
            

              Last active
              January 4, 2023 10:31
            

              
                Covert ECDH over secp256k1
              
          

        

      

        

  

      

    
  


  




    


          
    

      

        
        

          

              @ymgve
          

          

            
                ymgve
                / btftest.py
            
            

              Last active
              January 21, 2018 14:49
            

          

        

      

        

  

    
    


        



  


  

        

          
          import hashlib, os, struct, sys, socket, time
        

        

          
          

        

        

          
          N = 0xfffffffffffffffffffffffffffffffffffffffffffffffffffffffefffffc2fL
        

        

          
          R = 0xfffffffffffffffffffffffffffffffebaaedce6af48a03bbfd25e8cd0364141L
        

        

          
          A = 0L
        

        

          
          B = 7L
        

        

          
          gx = 0x79be667ef9dcbbac55a06295ce870b07029bfcdb2dce28d959f2815b16f81798L
        

        

          
          gy = 0x483ada7726a3c4655da4fbfc0e1108a8fd17b448a68554199c47d08ffb10d4b8L
        

        

          
          

        

        

          
          b58ab = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz"
        

  





    


  




    


          
    

      

        
        

          

              @karlgluck
          

          

            
                karlgluck
                / Hash Ladders for Shorter Lamport Signatures.md
            
            

              Last active
              March 31, 2024 17:53
            

              
                I describe a method for making Lamport signatures take up less space. I haven't seen anyone use hash chains this way before, so I think it's pretty cool.
              
          

        

      

        

  

      

    
What's this all about?


Digital cryptography! This is a subject I've been interested in since taking a class with Prof. Fred Schneider back in college. Articles pop up on Hacker News fairly often that pique my interest and this technique is the result of one of them.


Specifically, this is about Lamport signatures. There are many signature algorithms (ECDSA and RSA are the most commonly used) but Lamport signatures are unique because they are formed using a hash function. Many cryptographers believe that this makes them resistant to attacks made possible by quantum computers.


How does a Lamport Signature work?