I can tell you it won't. RSA, the best cipher available, uses two huge (1000 digit) primes to make a key, and it involves modular addition (too complicated to explain right now). Using those primes, and a certain product of those primes, it creates an encryption key e and a decryption key d. e is given to everybody, as well as N (something else needed to encypt based on modular addition), and everybody can encrypt and send to the person with the decryption key, d. However, because modular addition is as it is, you can't get d from e. The only way is to analyze N, which is made from the two primes, and attempt to brute force by finding all possible primes. It is proven that brute force will take longer than the age of the universe. So no.