Factoring the Seventh and the Eighth Fermat Number with ECM
He Zhi · Information Security and Communications Privacy · 2009
ECM is successfully used to decompose F7 and F8, while these two numbers are factored before using other methods. The proposed implementation is based on Victor Shoup?s the number theory library(NTL). It is found that the divisor decomposed by ECM may not be the smallest one and that the efficiency of ECM depends on the size of divisors.