Is takes O(k^4), where k is the length of the modulus. This can generally be done offline.How fast is RSA Encryption?
It takes O(k^3), and sometimes can be done offline.Examples
On a 90 MHz Pentium, throughput 2.7KB kbits per second with a 512-bit modulus and 0.925KB per second with a 1024-bit modulus.In software, DES is generally at least 100 times as fast as RSA. In hardware, DES is between 1,000 and 10,000 times as fast, depending on the implementation. Implementations of RSA will probably narrow the gap a bit in coming years, due to high demand, but DES will get faster as well.