Questions tagged [number-field-sieve]

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Complexity of number field sieve theorem does not match with security of elliptic curves

Number field sieve algorithm can is used to break discrete logarithm on field $F_{p^n}$. The algorithm has time complexity $\exp((c+o(1))\cdot(\log p^n)^{1/3}\cdot(\log \log p^n)^{2/3}$. Originally ...
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0answers
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Precomputation attacks against ECDH

Diffie-Hellman groups are vulnerable to sieving precomputation attacks. These attacks allow a one-time computation against a given DH modulus that makes it practical to attack all subsequent key ...
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0answers
216 views

Is the matrix step of GNFS still the hardest part?

When the factorization of RSA-768 was announced in December 2009: the sieving took about 24 months and the matrix step took 119 days (4 months). So sieving took about 6 times as long. This is despite ...
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165 views

What are the theoretical memory requirements for these factoring algotihms?

Given an $n$ bit integer quadratic sieve takes $L(\frac12,1+o(1))$ time and number field sieve takes $L(\frac13,1.922)$ time where $L$ notation is given in https://en.wikipedia.org/wiki/L-notation. ...
1
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1answer
136 views

Quadratic sieve for DLOG performance - theory vs actual?

Is there any report on comparing quadratic and number field sieve performance in theory vs actual data for discrete logarithm over primes? Is actual data better than theory in any way unexplained (I ...
1
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0answers
99 views

Is there any concrete working example for Function Field Sieve method?

I'm new to Function Field Sieve(FFS) (Number Field Sieve(NFS) as well) method and I'm finding it is quite difficult to understand it (especially concepts of valuation at infinity, Ca,b curves etc.) ...
3
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1answer
133 views

Combining Hellman Pohlig with Sieve

Suppose integer $m$ has $\phi(m)=2pq^5r^2$ where $p,q,r$ are primes. Hellman-Pohlig says that finding discrete log $z\bmod p$, $z\bmod q^5$, $z\bmod r^2$ and $z\bmod 2$ suffices to find $z\bmod\phi(m)...
2
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1answer
70 views

SNFS: Quantifying the “small” parameters?

The special number field sieve (SNFS) is an algorithm to calculate discrete logarithms and to factor numbers, given that the target has a special structure. Now, all ressources always say something ...