RAMus- A New Lightweight Block Cipher for RAM Encryption

Over the past decades, there has been a dramatic increase of the attacks recovering the data from the RAM memory. These have heightened the need for new solutions and primitives suitable for the encryption of this information. In this paper we introduce RAMus, a new tweakable lightweight block cipher whose properties support its usage for securing the RAM memory. In this sense, RAMus attains all the requirements provided by the (German) Federal Office of Information Security (BSI) in the domain of encryption algorithms suitable for RAM and memory encryption. The design strategy of RAMus is inspired from the LS-approach. Compared to the literature, in our proposal the linear layer is replaced by a second Sbox layer. In RAMus, the diffusion is ensured by the Sbox layers, which use Sboxes with a non-trivial branch number.