Why GF(2^n)?

Binary finite fields more convenient for hardware implementations because the elements of GF (2^n) can be represented by n-bit binary code words. Thus GF(2^n) is common for hardware implementations.
The addition operation in GF (2^n) is like the XOR operation on bit fields. That is x + x = 0 for all x ∈ GF (2^n). This implies that a finite field of form GF (2^n) is of characteristic 2.