reorderCode can end up being equal to 256, so we end up writing a 1 right past the end of the array. Doesn't seem like it could be super dangerous. code: // lead bytes that have alread been assigned to the permutation table bool newLeadByteUsed[256]; ... int reorderCode = 0; for (int i = 0; i < 256; i++) { if (!permutationSlotFilled[i]) { while (reorderCode < 256 && newLeadByteUsed[reorderCode]) { reorderCode++; } ... newLeadByteUsed[reorderCode] = true;