Complex sentence: Performance critical applications that have to use HTTPS (SSL/TLS), can benefit from the use an SSL Acceleration HSM by moving the generation of the session key, which typically requires several large integer multiplications, from the host CPU to the HSM device.
Split into simpler sentences: Performance critical Applications, that must use HTTPS (SSL/TLS), can benefit by using an SSL Acceleration HSM. The benefit is achieved by delegating the generation of the session key, which typically requires several large integer multiplications, from the host CPU to the HSM device.