Unknown key-share attack

As defined by Template:Harvtxt, an unknown key-share (UKS) attack on an authenticated key agreement (AK) or authenticated key agreement with key confirmation (AKC) protocol is an attack whereby an entity ${\displaystyle A}$ ends up believing she shares a key with ${\displaystyle B}$, and although this is in fact the case, ${\displaystyle B}$ mistakenly believes the key is instead shared with an entity ${\displaystyle E\neq A}$.