More on Bernstein's Number Field Sieve

Russ Nelson writes "Dan Bernstein has a response to Bernstein's NFS analyzed by Lenstra and Shamir, entitled Circuits for integer factorization. He notes that the issue of the cost of factorization is still open, and that it may in fact be inexpensive to factor 1024-bit keys. We don't know, and that's what his research is intended to explore."