rsa encryption

RSA encryption

   <cryptography, algorithm> A {public-key cryptosystem} for both
   {encryption} and {authentication}, invented in 1977 by Ron
   Rivest, Adi Shamir, and Leonard Adleman.  Its name comes from
   their initials.

   The RSA {algorithm} works as follows.  Take two large {prime
   numbers}, p and q, and find their product n = pq; n is called
   the modulus.  Choose a number, e, less than n and {relatively
   prime} to (p-1)(q-1), and find its reciprocal mod (p-1)(q-1),
   and call this d.  Thus ed = 1 mod (p-1)(q-1); e and d are
   called the public and private exponents, respectively.  The
   public key is the pair (n, e); the private key is d.  The
   factors p and q must be kept secret, or destroyed.  It is
   difficult (presumably) to obtain the private key d from the
   public key (n, e).  If one could factor n into p and q,
   however, then one could obtain the private key d.  Thus the
   entire security of RSA depends on the difficulty of factoring;
   an easy method for factoring products of large prime numbers
   would break RSA.

   RSA FAQ (http://rsa.com/rsalabs/faq/faq_home.html).

   (2004-07-14)