Quote from: yoshimitsu777 on Today at 09:17:38 AM

how did you find such a transaction that was using same R?
is there a tool available for the calculcation which takes those values as input argument and output the resulting private key?

Hello
You can use Same R cracker utility at following link.
offline https://github.com/nlitsme/bitcoinexplainer
online https://rawcdn.githack.com/nlitsme/bitcoinexplainer/aa50e86e8c72c04a7986f5f7c43bc2f98df94107/ecdsacrack.html

I have tested this work stable no bug.

Also possible in python

Code:

def Crack_K_Same_R(R,S1,S2,H1,H2):
t1 = pow((S1-S2), N-2, N)
TestK = 0
TestK = ((H1-H2) * t1) % N
if ((TestK*G).x.num == R):
print("!!!Winner!!! %064X " % TestK );
exit();
print("Not valid. %064X " % t1)

Once you have K = nonce you can extract private key X