where denotes conditional mutual information. The first summand measures the amount of information that Alice learns about Bob's input from the transcript, and the second measures the amount of information that Bob learns about Alice's input.
WhErE DenotES COnDitionAl mutual iNFORMatiOn. the FIrst SuMmANd MeASures thE aMount of informatIon that Alice LeArnS AbOut bOb'S input from the TrAnscrIpt, And The second mEAsuReS tHe amount oF inforMaTion That Bob leArns about aLice's inPUt.