$b$-jet identification algorithms and performance in the ATLAS experiment

For many physics programs at the LHC, the ability to identify jets containing $B$-hadrons ($b$-tagging) is a crucial ingredient. This is particularly useful to select very pure top samples, to search for the Higgs boson which decays to the $b$-quark pairs with the largest branching fraction at the mass of 125 GeV and to search for new physics phenomena which are expected to contain $b$-quark(s) in their final states. After brief reviews of the $b$-tagging algorithms developed in the ATLAS experiment, novel approaches to measure the $b$-tagging efficiency of $b$-, $c$-, and light-jets are presented.