A computer-implemented method includes encoding an array of (p−1)×k symbols of data into a p×(k+r) array. The method includes p is a prime number, r≥1, and k≤p. The method includes each column in the p×(k+r) array has an even parity and symbol i in column r+j, for 0≤i≤p−1 and 0≤j≤r−1, is the XOR of symbols in a line of slope j taken with a toroidal topology modulo p in the k columns starting in symbol i of column 0.