In this thesis we study dierent aspects of the asymptotic symmetries of the gravitational eld as described by general relativity. We rst brie y recall the surprising fact, uncovered by Bondi, van der Burg, Metzner and Sachs (BMS) [1]{[3] in the 1960s, that in the limit of a vanishing gravitational eld the symmetry of spacetime does not reduce to the Poincare group but is in fact described by an innite-dimensional generalization thereof. In what follows this BMS group will be the central object of our interest. The following chapter is devoted to the analysis of asymptotic symmetries in the Hamiltonian formulation of general relativity. We revisit previous treatments [4, 5] and nd that at spatial innity a symmetry which is even larger than BMS can be obtained. It has been shown by Witten [6] in the 1980s that 2+1 dimensional gravity is completely equivalent to a specic gauge theory with Poincare as gauge group. We investigate the question whether it is possible to obtain a gauge theory with BMS as gauge group. Next we turn to the topic of the deformation of symmetries. After reviewing the mathematical notions of Hopf algebras and twist deformations we generalize the -deformation [7]{[11] of the Poincare to the BMS algebra. We then consider the topic of black hole entropy and revisit one of the earliest attempts of a microscopic explanation of its origin by 't Hooft [12]. By including backreaction eects we nd a natural explanation for a certain regulator, which has been introduced ad-hoc by 't Hooft, and thereby remove the previous need to ne-tune its value. Lastly, we review the information loss paradox and how it might be connected to the BMS symmetry [13] and point out that our results from the -deformation of the BMS algebra could be relevant in this context. i