It’s not quite a doubling per bit, which is why RSA keys are relatively large compared to similar-strength ECDSA keys, for example.
Steve Weis, who has been doing RSA factoring on some large GPU clusters, estimates factoring 1024-bit RSA would take about 2000 GPU-years, which is well within the range of anyone with a serious budget.
Steve Weis, who has been doing RSA factoring on some large GPU clusters, estimates factoring 1024-bit RSA would take about 2000 GPU-years, which is well within the range of anyone with a serious budget.