Technologies for preventing software -based side-channel attacks are generally disclosed. In some examples, a computing device may receive a cryptographic program having one or more programming instructions for performing a key handling operation and may add one or more programming instructions for performing an anti-attack operation to the one or more programming instructions for performing the key handling operation. The computing device may transmit the resulting cryptographic program with the anti-attack operation to an execution device. The execution device, such as a cloud computing system, may execute the cryptographic program, thereby causing execution of the anti-attack operation. The execution of cryptographic program may prevent a side-channel attack by masking the number of key performance events that occur.