A cryptographic accelerator is a device that performs processor-intensive decrypting/encrypting while freeing the host CPU to perform other tasks. In general cryptographic accelerator is a co-processor. Common use for cryptographic accelerator is a webserver protecting data transmitted through insecure network with SSL (SSL acceleration

SSL acceleration

SSL acceleration is a method of offloading the processor-intensive public key encryption algorithms involved in SSL transactions to a hardware accelerator....

). Physically cryptographic accelerator is usually an add-on card that fits into computers expansion slot like PCI or PCIe.