And the trip in the history could easily continue. Yet, the main boom of cryptography as a scientific branch came with both world wars. The diplomats and the army always needed to hide their sensitive information from the curious eyes of their enemies. After the wars it was the rapid process of the mass computerised processing of data that brought along another fast development of cryptography. From different techniques multi-purpose encryption algorithms evolved.
Algorithms are certain general mathematical processes, which say how to encrypt a given text.
To ensure, that an encrypted text cannot be decrypted by anyone using just this general process, an encryption key comes onto the scene something unique for a given encrypted text. Such encrypted text cannot be usually decrypted without the knowledge of the encryption key. All aspects and relations of this scientific branch are fully understandable only to a few 'privileged'. There is nothing mysterious about them they are most of all excellent mathematicians. It was only the lack of knowledge that placed on them and this whole area the shadow of perplexity.