bn2string
else if ((x = bn2string(X)) == NULL)
else if ((y = bn2string(Y)) == NULL)
else if ((mod = bn2string(RSA_get0_n(r))) == NULL)
else if ((exp = bn2string(RSA_get0_e(r))) == NULL)
else if ((x = bn2string(X)) == NULL)
else if ((y = bn2string(Y)) == NULL)
else if ((mod = bn2string(RSA_get0_n(r))) == NULL)
else if ((exp = bn2string(RSA_get0_e(r))) == NULL)