H(X)=−∑x∈XP(x)logbP(x)cap H open paren cap X close paren equals negative sum over x is an element of cap X of cap P open paren x close paren log base b of cap P open paren x close paren where the unit is if Channel Capacity (

Information theory identifies two fundamental limits in any communication system: Entropy (

Information theory provides the basis for assessing the strength of encryption (e.g., assessing the entropy of keys).