 Message modification is an attack in which an attacker intercepts messages and changes their contents. Assume Alice asks Bob to pay €100. If the attacker is able to perform a so-called men-in-the-middle attack, messages that are sent by Alice will be intercepted by the attacker, who may subsequently modify the amount to €1,000 and forward the modified packet to Bob. Message modification requires the ability to block direct communication between Alice and Bob, for example by DNS hijacking or BGP redirection, followed by the ability to masquerade as Alice while sending data to Bob.