The quadratic sieve algorithm (QS) is an integer factorization algorithm and, in practice, the second fastest method known (after the general number field sieve). It is still the fastest for integers under 100 decimal digits or so, and is considerably simpler than the number field sieve.
Considering this, how fast is quadratic sieve?
The QS was the fastest known factoring algorithm until the Number Field Sieve was discovered in 1993. Still the QS is faster than the Number Field Sieve for numbers up to 110 digits long.
Furthermore, what is SIQS? The self-initializing quadratic sieve (SIQS) is a factorization method based on the multiple polynomial quadratic sieve (MPQS).