This is a binary error correcting code consisting of only 2 codewords, namely, the all one vector and the all zero vector. Because of this code's simplicity, it's not of much use in practice, but it provides us with a valuable base case when proving properties of other codes.

The generator matrix of the [n,1] repetition code is simply the all one vector [111...1] of length n. The parity check matrix of the code is the [n,n-1] code consisting of all even weight vectors of length n.