The term crypto has become overloaded recently with the introduction of all currencies, such as Bitcoin, Ethereum, and Litecoin. When we refer to crypto as a form of protection, we are referring to the concept of cryptography applied to communication links, storage devices, software, and messages used in a system. Cryptography has a long and important history in protecting critical systems and sensitive information.

During World War II, the Germans used Enigma machines to encrypt communications, and the Allies went to great lengths to crack the encryption. Enigma machines used a series of rotors that transformed plaintext to ciphertext, and by understanding the position of the rotors, the Allies were able to decrypt the ciphertext into plaintext. This was a momentous achievement but took significant manpower and resources. Today it is still possible to crack certain encryption techniques; however, it is often more feasible to attack other aspects of cryptographic systems, such as the protocols, the integration points, or even the libraries used to implement cryptography.

Cryptography has a rich history; however, nowadays, you will come across new concepts, such as blockchain, that can be used as a tool to help secure the IoT. Blockchain is based on a set of well-known cryptographic primitives. Other new directions in cryptography include quantum-resistant algorithms, which hold up against a theorized onslaught of quantum computers and quantum key distributions. They use protocols such as BB84 and BB92 to leverage the concepts of quantum entanglement and create good-quality keys for using classical encryption algorithms.