Conversely, cryptanalysis is the art and science of breaking encoded data. The branch of mathematics encompassing both cryptography and cryptanalysis is cryptology. It needs to be made clear however, that cryptography is not a panacea for information security. Poorly implemented cryptosystems are weak and susceptible to attack. Similarly, generally poor IT security weakens a cryptosystem's effectiveness.
Cryptography therefore needs to be seen in the overall context of IT security.
So, both the originator and the intended recipient must have an identical copy of the encryption key. Messages encrypted with the public key can only be decrypted with the private key. This form of encryption goes some way to overcome the problem that arises with symmetrical key encryption. Digital signatures Partly because of asymmetric key cryptography we now have digital signatures. There is more than one way to create a digital signature.