Improved Stage 2 to P±1 Factoring Algorithms

Some implementations of stage 2 of the P-1 method of factorizationuse convolutions. We describe a space-efficient implementation,allowing convolution lengths around 223 and stage 2 limit around1016 while attempting to factor 230-digit numbers on modern PC's. Wedescribe arithmetic algorithms on reciprocal polynomials. We present adjustmentsfor the P+1 algorithm. We list some new findings.