Cryptography has made a peculiar journey to become a modern science. It had long been
associated with the military and with magic. The rst published work in the eld was
Steganographia, by an alchemist named Trithemius. Although written earlier, the book was
published in 1606. Cryptography has continued this connection with the arcane | during
World War II, intelligence derived from the broken Japanese PURPLE cipher was code
named Magic .
Because of the association with the military, and cryptography's importance for warfare
and tradecraft, it confronted a restrictive status quo as cryptography's usefulness started
to expand beyond its established boundaries. During a period beginning around 1976, the
needs of commerce for condentiality over electronic communication channels and the public
study of cryptography to satisfy those needs meant that cryptography had to nally walk
out of its cloisters among the government agencies and become a science, as had other
sciences walked away from unnecessary and restrictive strictures .
It was not just an amazing change, but a change that was the best and most direct
expression of the change of our times into an information age and an information economy.
It was part and parcel of the recognition of a cyberspace, in which a cybersociety will be
At the technical end of things, the invention of public key encryption was by far the
greatest enabler of these changes. At its birth, in the New Directions paper [1, 2], along
with a new sort of cryptography, better able to deal with the ad hoc patterns of civil
communication, there was the proposal of a digital signature, that is, a method by which
it can be publicly veried that a signer has agreed to a document. In solving this problem,
cryptography now had become another thing. It was thereafter a great misrepresentation
and underestimation to describe cryptography as being about secret messages, or of only
keeping things condential.
Immediately afterwards emerged blind signatures to enable untraceable cash. Cryptography
broadened out of its traditional military context, into a nancial context, with an
immediate challenge to culture. Untraceable electronic cash is as much an awesome discovery
as it is a threat to the status quo. At each unfolding of cryptography, at each new
direction, something about culture, commerce, and freedom needed to be renegotiated.