48 bytes get expanded to 751. Whether you count this as 751 or 48 depends on what you want to compare. Also, your description implies DH exchanges are zero kno

48 bytes get expanded to 751. Whether you count this as 751 or 48 depends on what you want to compare. Also, your description implies DH exchanges are zero knowledge exchanges - that there is no way to infer the private key from the public exchange - but that's not true. It is perfectly possible - in fact, in most DH variants a 1-1 transformation - except it is entirely infeasible.