Hello, After evaluating the time performance of RSA and ECC key generation algorithm and RSA and ECDSA signature generation and verification. I found some result that i could not explain so i am asking you about your point of view and thanks for answering.
Questions: - Why the ECDSA verification time is always greater than the RSA one. Personaly i thought that it is caused by the mathematical difficulty of ECDSA verification when comparing it to RSA signature verification but if i consider the mathematical complexity as cause i will conclude also that ECDSA generation should take more time than RSA signature generation but it is not true. In addition i found that ECDSA verification can be faster than RSA on some devices such as tablet PC so that means that ECDSA depends on the device 's processor and its frequency. what you think about this? - the fact that ECC key has shorter key length (modulus length) that gives the same level of security as RSA key having bigger length (for example ECC having 163 bits length is equivalent to RSA having 1024 bits length) is only due to the fact that ECC theory is more complex than RSA one or there is other explanation? - why SHA256 will not work with key that are inferior to 256 bits in length (modulus length)? thank you for the help. -- Aymen
