RSA is a public-key cryptosystem and is widely used for secure data transmission. In such a cryptosystem, the encryption key is public and it is different from the decryption key which is kept secret (private). In RSA, this asymmetry is based on the practical difficulty of the factorization of the product of two large prime numbers, the "factoring problem".
With this app you can encrypt messages using the RSA algorithm.
This app will help you to understand the calculation behind the RSA algorithm.