im looking at wiki at the moment as how to use oeap padding and it appears, help me out if im wrong as G(r) - expands r to the size of the padded message, I am then limited by the size of my hash function as say a SHA-256 hash function would expand to only 256 bits, but what if I had a 2048 bit modulus? I'm unsure if there are any 2000+bit hash functions out there, or could I use a series of different r values, hash them and use the concatenation of the hash outputs to create a 2000 bit xor?