Book: The Queen.
PLEASE NOTE: The Tower Cryptography operates under many false beliefs.
By the Queen's mercy, the Reef Cryptography will educate you on the true nature of encryption, if you so desire.
In ancient times, Earthlings thought there were three states of matter. We now know there to be four: solid, liquid, gas and engram. Of these, the engram is the purest state of matter.
The role of the Cryptarchy is to encrypt and safeguard civilization's informational infrastructure, not to decrypt anything and everything for any lowdown scavenger who happens upon an engram.