Cryptography Reference
In-Depth Information
the transaction or claim that it was for a different amount.
All of these concerns, and more, have to be met before the
simplest e-commerce transactions can be made securely.
As a result, cryptology has been extended far beyond its
original function of providing secrecy.
The conduct of commerce, affairs of state, military
actions, and personal affairs all depend on the existence
of generally accepted means of authenticating identity,
authority, ownership, license, signature, notarization,
date of action, receipt, and so on. In the past these have
depended almost entirely on documents, and on protocols
for the creation of those documents, for authentication.
Society has evolved and adopted a complex set of legal
and forensic procedures, depending almost entirely on the
physical evidence intrinsic to the documents themselves,
to resolve disputes over authenticity. In the information
age, however, possession, control, transfer, or access to
real assets is frequently based on electronic information,
and a license to use, modify, or disseminate valuable infor-
mation itself is similarly determined. Thus, it is essential
that internal evidence be present in the information
itself—since that is the only thing available. Modern cryp-
tology, therefore, must provide every function presently
served by documents—public and private. In fact, it fre-
quently must do more. When someone mails a document
by certified mail with a request for a delivery receipt, the
receipt only proves that an envelope was delivered; it says
nothing about the contents. Digital certificates of origina-
tion and digital receipts, though, are inextricably linked
to each electronic document. Many other functions, such
as signatures, are also much more demanding in a digital
setting. In June 2000 the U.S. Congress gave digital signa-
tures the same legal status as written signatures—the first
such legislation in the world.
