Crypto processor
A cryptoprocessor is a special microprocessor which is designed as a microcontroller or as a system-on-a-chip , and which, in addition to the use of cryptographic operations, includes additional units and software for implementing the basic functions of a security system. Cryptoprocessors are used as a central component in smart cards , Trusted Platform Modules (TPM) or security tokens , among other things .
Since, in principle, direct physical access to the hardware is possible for an attacker with a cryptoprocessor, as in the use of a smart card, these processors have hardware or memory that is specially secured against unauthorized physical access, which is located directly on the semiconductor chip, in order to allow targeted manipulation to complicate ( English tamper resistance ). These methods include, inter alia, directly on the attached electrically conductive layers, which, for the determination of the internal structure. B. aggravate by chemical methods or thin section . This also prevents direct electrical access to internal control signals. For this reason, the entire system including peripheral units on a single semiconductor chip (at cryptoprocessors English The housed). Further hardware measures can be the automatic deletion of internal storage elements, for example as soon as an attempt is made to mechanically open the chip housing .
Depending on the system, in addition to the special structure of the hardware and when using external memory, the data in the external bus interface is decrypted and encrypted during runtime. In the area of the software used, special temporal behaviors are selected which make it more difficult to obtain stored and secret information indirectly, for example through slight fluctuations in power consumption or through differences in the temporal response behavior.
Individual evidence
- ^ A b Ross Anderson, Mike Bond, Jolyon Clulow, Sergei Skorobogatov: Cryptographic Processors - A Survey . Ed .: IEEE. 2005 ( online [PDF]).
- ↑ Reouven Elbaz, Lionel Torres, Gilles Sassatelli, Pierre Guillemin, Claude Anguille, et al .: Hardware Engines for Bus Encryption: a Survey of Existing Techniques. Ed .: DATE: Design, Automation and Test in Europe. Munich 2005, doi : 10.1109 / DATE.2005.170 .