BigIntn returns a uniform random *big.Int in [0,n).

Bytes is a helper function that returns n bytes of random data.

Intn returns a uniform random int in [0,n).

Perm returns a random permutation of the integers [0,n).

Read is a helper function that calls Reader.Read on b.

Uint64n returns a uniform random uint64 in [0,n).

Reader is a global, shared instance of a cryptographically strong pseudo- random generator.