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elliptic code of 112 bit

asked 2018-03-03 00:18:23 -0500

santoshi gravatar image
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answered 2018-03-03 09:55:47 -0500

dan_fulea gravatar image

Let us consider the "simpler" situation for the degree of the cyclotomic polynomial:

p = ZZ( (2^128-3)/76439 )
F = GF(p)
S.<W> = PolynomialRing( F )
K.<w> = GF( p^2 )

R.<z> = PolynomialRing( K, sparse=True )
# N = 9817501343317677957515279627338949795623675802414662483433914174328
N = 2^3 * 17 * (1000.next_prime())
f = cyclotomic_polynomial( N, 'z' )
len(f.monomials())

This code constructs $f$ having

4985

monomials. The value of $N$ is

sage: N
137224

and it is "small", when compared to the "bigger" number

sage: 9817501343317677957515279627338949795623675802414662483433914174328.factor()

2^3 * 17 * 72187509877335867334671173730433454379585851488343106495837604223

For this smaller $N$, the polynomial $f$ was computed and stored. It is of course no place to store the corresponding data for the "bigger" number instead. And the code for the computation of the cyclotomic polynomial was designed for such practical situations.

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Asked: 2018-03-03 00:18:23 -0500

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Last updated: Mar 03