We present empirical results that suggest that there are real quadratic fields with properties similar to imaginary quadratic fields in terms of size and structure of the class group. Therefore, these class groups can also be used for encryption schemes such as the ElGamal scheme, where up to now, only class groups of imaginary quadratic fields have been considered. Some security aspects are also addressed.
"On real quadratic number fields suitable for cryptography." Experiment. Math. 14 (2) 189 - 197, 2005.