ant to find out how the quality of primes is ensured. Naive users usually think that in order to cre- ate that effect, large random numbers are generated and then the system tries to factor them in order to ensure that a generated number (intended to be a prime) is a prime. Many different probabilistic primality testing algorithms are available and a system at configuration time or at design time was put together in such a way that it allows the setting of a threshold of acceptable failure risk in the gener- ation of such numbers. The embedded cryptographic system will then generate large random num- bers and apply one or more primality tests to them. These test are run with a varying degree confidence based on the risk threshold stipulated by the user. The system will make a judgment as to whether the generated number is indeed prime. The subject has fascinating ramifications, but it goes way beyond the coverage of our chapter. The following are a few other well-known public-key techniques: The unpatented El-Gamal system, which is similar in approach to the DH and RSA processes, but in terms of encryption, the ciphertext is twice as long as the plaintext. The DSS, which is standardized as FIPS-186. Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. SECURITY COPROCESSORS 384 NETWORK PROCESSORS The lattice-cryptography-based NTRU cryptosystem, which is starting to make a significant inroad in the wireless market due to its speed and modest computational resource requirements. The com- pany's web site contains a series of white papers and excellent tutorials (see www.ntru.com). Elliptic-curve cryptography (ECC) and some more recent variations of its principles such as hyper- elliptic-curve-based cryptography. In the last few years, ECC public-key cryptography has become a potential large-scale contestant, as it offers similar levels of protection