52, 53, 54, 55, 56, 57, 58, 59, 60, 61, xx, xx, xx, xx, xx, xx
xx, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14
15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, xx, xx, xx, xx, 63
xx, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40
URL Safe Base64 in Objective-C