Encryption is a special case of conditional loss-less transformation and is, thus, interesting to study from the perspective of reversible computations. In this paper we investigate some of the advantages of implementing encryption algorithms in a reversible language; here exemplified by implementing several symmetric lightweight encryption algorithms in Janus. We not only get both encryption and decryption programs with the same implementation, but also demonstrate how to translate the Janus program to a Vale program, which is then intended to be used to formally show the absence of state information leakage. This shows a way to use reversible programming to increase resilience to some side-channel attacks and give prospects for writing more secure algorithms in the future. Our experience shows that the implementation time is not significantly increased when implementing the algorithms in Janus.