how to avoid error " OverflowError: Python int too large to convert to C long

asked 2017-11-14 18:41:40 +0200

this post is marked as community wiki

This post is a wiki. Anyone with karma >750 is welcome to improve it.

i have implemented algorithm for point addition and doubling of elliptic curve arithmetic based on single variable. now i am working on NIST prime curve. p-192

p=6277101735386680763835789423207666416083908700390324961279 k. = FiniteField (p^2) ; k R.<z> = PolynomialRing( K, sparse=True )

computed x and y from algorithm

x= (2092367245128893587945263141069222138694636233463441653760a + 4184734490257787175890526282138444277389272466926883307520)z^6277101735386680763835789423207666416083908700390324961279 + (4184734490257787175890526282138444277389272466926883307519a + 2092367245128893587945263141069222138694636233463441653760)z

y= (4184734490257787175890526282138444277389272466926883307520a + 2092367245128893587945263141069222138694636233463441653760)z^6277101735386680763835789423207666416083908700390324961279 + (2092367245128893587945263141069222138694636233463441653759a + 4184734490257787175890526282138444277389272466926883307519)z

i want to compute line equation of elliptic curve using above x and y in terms of z. the equation is

fL=(((Q[0]-P[0])y)-((Q[1]-P[1])x)-(P[1]Q[0]-Q[1]P[0])) where P and Q are point on the elliptic curve .

the sagemath is unable to compute fL it gives me error overflow error Python int too large to convert to C long how to reduce this error.

edit retag flag offensive close merge delete

Comments

1

Please use that button with

101
010

to mark code. As above! Else all we get is a mess.

Again, i have no chance to understand the question.

  • We do not have the curve.
  • We have points that contain a z, which is an element of a polynomial ring. This ring has infinitely many elements. So the points do not live over a finite field.
  • Please give a reference to the curve, where is its equation? Where does the point $(x,y)$ come from?
  • You have implemented an algorithm for point addition and multiplication again and again. OK. Here we will use the one provided by sage. This information is misleading.
  • What does it mean i want to compute line equation of elliptic curve using above x and y in terms of z? Which "Line equation"?
  • How does the error arise? Give the code!
dan_fulea gravatar imagedan_fulea ( 2017-11-14 22:47:43 +0200 )edit
add a comment