by Lehrstuhl für Kryptologie u. IT-Sicherheit, Ruhr-Universität Bochum, published on 2010-10-25
To achieve a very fast decryption in RSA, one might choose the secret key to be rather small. It should, however, not be too small, since then it might be possible to mount brute-force attacks. The same holds for variants like RSA-CRT.