Sometimes it is necessary to protect information against unauthorized use.
To this end we want to transform this information into a coded message
which can be read by authorized people only. For this we can use the
RSA cryptosystem. Of course, it is possible to first transform arbitrary data
into numbers. The RSA cryptosystem can then encode a given number into
a secret number and it can also decode this secret number. We need
the following ingredients:
RSA ingredients
- Two primes p and q;
- an encoding number v and a
decoding number w
with
vw = 1 mod (p - 1)(q - 1).
The primes p, q and the decoding number w are
secret. The encoding number v and the modulus m = p · q need not be secret; they can be public.