The science of cryptography is very difficult, much like the science of building stronger, better buildings is difficult. However, the actual use of cryptography is only slightly more difficult than walking through the door of a building.
The amount of information available about cryptography could fill many books.
In fact, many books have been written about it. However, this
document only attempts to answer the most common questions about cryptography,
and will even attempt to get you started on your way to successfully using
it on a daily basis.