Editing Secure cryptoprocessor (section)

==Examples==
A [[hardware security module]] (HSM) contains one or more secure cryptoprocessor [[integrated circuit|chips]].<ref>{{cite book |last1=Ramakrishnan |first1=Vignesh |last2=Venugopal |first2=Prasanth |last3=Mukherjee |first3=Tuhin |title=Proceedings of the International Conference on Information Engineering, Management and Security 2015: ICIEMS 2015 |date=2015 |publisher=Association of Scientists, Developers and Faculties (ASDF) |isbn=9788192974279 |page=9 |url=https://books.google.com/books?id=Gw9pCwAAQBAJ&pg=PA9}}</ref><ref name="f5">{{cite web |title=Secure Sensitive Data with the BIG-IP Hardware Security Module |url=https://www.f5.com/pdf/solution-profiles/hardware-security-module-sp.pdf |publisher=[[F5, Inc.|F5]] |date=2012 |access-date=30 September 2019}}</ref><ref name="Gregg">{{cite book |last1=Gregg |first1=Michael |title=CASP CompTIA Advanced Security Practitioner Study Guide: Exam CAS-002 |date=2014 |publisher=[[John Wiley & Sons]] |isbn=9781118930847 |page=246 |url=https://books.google.com/books?id=LKPCBwAAQBAJ&pg=PA246}}</ref> These devices are high grade secure cryptoprocessors used with enterprise servers. A hardware security module can have multiple levels of physical security with a single-chip cryptoprocessor as its most secure component. The cryptoprocessor does not reveal keys or executable instructions on a bus, except in encrypted form, and zeros keys by attempts at probing or scanning.  The crypto chip(s) may also be [[Potting (electronics)|potted]] in the hardware security module with other processors and memory chips that store and process encrypted data. Any attempt to remove the potting will cause the keys in the crypto chip to be zeroed. A hardware security module may also be part of a computer (for example an [[automated teller machine|ATM]]) that operates inside a locked safe to deter theft, substitution, and tampering.

Modern [[smartcard]]s are probably the most widely deployed form of secure cryptoprocessor, although more complex and versatile secure cryptoprocessors are widely deployed in systems such as [[Automated teller machine]]s, TV [[set-top box]]es, military applications, and high-security portable communication equipment.{{citation needed|date=May 2016}} Some secure cryptoprocessors can even run general-purpose operating systems such as [[Linux]] inside their security boundary. Cryptoprocessors input program instructions in encrypted form, decrypt the instructions to plain instructions which are then executed within the same cryptoprocessor chip where the decrypted instructions are inaccessibly stored.  By never revealing the decrypted program instructions, the cryptoprocessor prevents tampering of programs by technicians who may have legitimate access to the sub-system data bus. This is known as [[bus encryption]]. Data processed by a cryptoprocessor is also frequently encrypted.

The [[Trusted Platform Module]] (TPM) is an implementation of a secure cryptoprocessor that brings the notion of [[trusted computing]] to ordinary [[Personal computer|PC]]s by enabling a [[secure environment]].{{citation needed|date=May 2016}} Present TPM implementations focus on providing a tamper-proof boot environment, and persistent and volatile storage encryption.

Security chips for embedded systems are also available that provide the same level of physical protection for keys and other secret material as a smartcard processor or TPM but in a smaller, less complex and less expensive package.{{citation needed|date=May 2016}} They are often referred to as cryptographic [[authentication]] devices and are used to authenticate peripherals, accessories and/or consumables. Like TPMs, they are usually turnkey integrated circuits intended to be embedded in a system, usually soldered to a PC board.