Linear complementary dual (LCD) codes and linear complementary pairs (LCP) of codes have been proposed as counter-measures against side-channel attacks (SCA) and fault injection attacks (FIA) in the context of direct sum masking (DSM). Although LCD codes were introduced by Massey long ago for other reasons, there has been a renewed interest in coding theory community for these kinds of codes due to these new applications. It has later been observed that the counter-measure against FIA may possibly lead to a vulnerability for SCA when the whole algorithm needs to be masked (in environments like smart cards). This led to a variant of the LCD and LCP problems, where some partial results have been very recently obtained by the authors. This chapter reviews the coding theoretic problems and solutions related to the security problems mentioned.