Encryption rises as secret, coded, hidden way to transfer information. Although it was born on military needs, rapidly grow in interest to keep our sensitive information safe. In the present time, all information transmitted has some type of encryption, from simple text message coming from your cellphone to email, bank transactions and of course military sensitive information.Most modern information is now transmitted in digital form, then is fundamental how to code and decode digital information with a safer and "simple" method. The aim of this book is to guide the reader into encryption, as how is cryptography present in their lives, at almost every aspect without even notice it. Major advances in encryption are being made to achieve secure transactions, secure communications and even to impact on the way economy works, emerging as a tool not only for secrecy but as a seed to a different approach to see the modern world.The book starts with an introduction to encryption, historical and basis. Using some simple examples will guide the reader to the relevant ideas behind cryptography, the encryption of messages. Section 1 is mainly focus on basis but taking the reader into more deep understanding of the different schemes used to encrypt a message.Section 2 deals with one interesting scheme of encryption, chaotic. Although is not a proved a standardize practice in cryptography, the methods are by far interesting and promising in achieve a completely encrypted message.Section 3 and 4 presents some simple applications in modern world. In the third, image encryption enters into the scene, as schemes by itself, but also by the need of encrypt each bite of information stored in images. The fourth section introduces bitcoins, as an alternative in economy based almost purely on encrypted operations.