For instance while looking at the transaction stack of my address, tracing it to exchanges I use, I came across this:
The same ScriptSig occurs twice on this page within the same transaction?
I know reading years ago in paper by someone was outlining how you can derive the private key from the scriptsig but I remember you need to have way more data in the field...in other words: the value between two inputs should match but there were other different values? Here it's just the exact same string but occuring twice?
aka, example of signature I am sure it's hackable:
(some header data) + (vulnerable data that occurs in other inputs) + (some more data)
very dumbed-down example:
00207777777777777777777777777123123 <- input1; 00217777777777777777777777777000000 <- input2
then by doing some simple math people can get the private key from input1 and input2 (multiplying/dviding etc, forgot how it worked just because the middle is the same of both inputs).
I have no idea what is 'witness' either, guessing miner who confirmed it?