The following link contains details on how to reverse the ECDSA signature if given two identical “R” values.
http://www.nilsschneider.net/2013/01/28/recovering-bitcoin-private-keys.html
I have read over this and there’s one part I don’t understand; how he got the “z” values.
Does a copy and paste of
“OP_DUP OP_HASH160 70792fb74a5df745bac07df6fe020f871cbb293b OP_EQUALVERIFY OP_CHECKSIG” (minus the quotations) into a ripemod-160 hashing function produce that result?
Did he have to essentially copy and paste some other string? Did he just ripemod or sha 256d? Did he have to do it more than once?
I’ve read up on these things but I just cannot decipher their programming description of how to do it. The non-programming descriptions don’t show “hey this ‘xyzx’ is what I’m referring to when I say ‘message to be signed'” or whatever. Many things on that page and on the
https://blockchain.info/tx/9ec4bc49e828d924af1d1029cacf709431abbde46d59554b62bc270e3b29c4b1
Seem as though they could adequately be described as the “message to be signed” besides the fact I don’t know what type of hash is being applied to even compare my calculations with the ones shown on the first link.
