This page allows you to simulate the behavior of the RSA cipher (see the page RSA: the method for details); the user has to enter two distinct primes $p$ and $q$, and then the plain message, here a number less than $ N = pq $. As a default example we use the current year, $ 2021 = 43 \times 47 $ which happens to be the product of two prime numbers.
As usual we imagine two people Alice and Bob, who have to exchange a message in a secret way, in this case it is just a number, but obviously any text can be transformed into numbers using a code, typically the ASCII code.
In the table on the right below the various steps of the encryption process are visible, the last two rows show the encrypted message and the decrypted one which must obviously be equal to the initial number.
NB 1 To avoid overload please use only prime numbers less than $200$.
NB 2 Presently RSA is considered secure only for 1024, or better 2048 bits numbers (hundreds of decimal digits!!!). This page has only a demo purpose, so it can only handle small and readable numbers.
