Iam working on RSA algorithm. I need to understand how one can work with large numbers as long as 100 digits , large prime generations. And then we need to add , * , / , ^ such large numbers .But no programming language gives us the way to deal with numbers as long as 100 digits. In java the limit is 19 - 20 digits. What is the possible solution to this problem . And is there any RSA algorithm (practical one) available any where on net.

Over 200 digits is not uncommon. "But no programming language gives us the way to deal with numbers as long as 100 digits" Read some of this: http://pajhome.org.uk/crypt/rsa/implementation.html Note the .BigInteger (as in java.math.BigInteger). http://www.cs.appstate.edu/~sjg/class/1010/mathematician/rsa.html http://oregonstate.edu/dept/honors/makmur/ http://www.di-mgt.com.au/rsa_alg.html http://www.cryptix.org/

Also note that java has quite a few RSA classes available for use, and they do seem to use BigInteger. See what they've got at http://java.sun.com/j2se/1.4.1/docs/api/ -SN