Public RSA key

The public RSA key (N,e) consists of RSA modulus N – the product of two prime numbers p and q – and the public exponent e. Anyone can obtain access to the public RSA key.

This means that anyone can encrypt a message using the public key. But only the owner of the associated secret key can then decrypt the message again.

Conversely, a message that was encrypted using the secret RSA key can be decrypted by anyone. This is how digital signatures are implemented.