A Secure Cryptoprocessor is a dedicated chip or microprocessor carrying out cryptographic operations, mostly embedded together with various physical security measures, and providing a degree of tamper resistance. For example, smartcards are well-known forms of secure cryptoprocessors, although more complex cryptoprocessors are widely deployed in sensitive systems, such as Automated Teller Machines.
Hardware Security Modules (HSM) are secure cryptoprocessors for managing digital keys, accelerating cryptoprocesses in terms of digital signings, and for providing strong authentication to access critical keys for server applications. Such modules are physical devices traditionally in the form of plug-in cards or external TCP/IP security devices, which can be attached directly to a computer (server or general-purpose computer). HSMs can notably be used to deliver digitally signed data, such as timestamps. Digital signature generally means data appended to, or a cryptographic transformation of, a data unit that allows a recipient of the data unit to prove the source and integrity of the data unit and protect against forgery. Please see also Cryptography.
