RSA encryption/decryption is based on a formula that anyone can find and use, as long as they know the values to plug in. Given the encrypted number 150815, d = 1941, and N = 435979, what is the decrypted number?
In order to decrypt the message we have to take a look at this equation, as shown in Wikipedia entry.
m = c^d % n
So it's just a matter of computing this m number, as everything is provided in the challenge.
Easy and fun, right?