Cryptography, Blockchain, Ethereum, ICO, Bitcoin.
Identity element: e in G exists such that for all a in G, e • a = a • e = a Inverse element: For every a in G, a⁻¹ exists in G such that a • a⁻¹ = e One particularly interesting group is called (ℤ/pℤ)ˣ , the multiplicative group of integers modulo p, especially when p is prime (that we will call