A system and method for providing a scrambled counter mode encryption for a device that mitigates the effect of side channel attacks based on differential power analysis (DPA). The scrambled counter mode encryption engine creates noise at the start of the encryption process by obfuscating the counter value with the use of the very fast mixing function, such as a mixing function based on a XOR tree, substitution-permutation networks, or double-mix Feistel networks. The mixing function uses some secret key material, which diversifies its behavior between different instantiations. Because the counter values are scrambled and the mixing functions operate very fast in parallel hardware, the input of the block cipher is pseudorandom and groups of blocks can't be correlated. The output of the block cipher is XORed with a plaintext message to obtain a cipher text message.