Even in the early days of networking, data transmitted between mutually friendly sites needed to traverse
complex and unpredictable sets of routers and communications lines. While there was some interest in end-to-end encryption
of potentially sensitive data, implementation was limited.
Unauthorized Access to Services and Data
Even in the early Internet's collaborative environment, it was important to identify and distinguish
users, so that data and costly processing resources could be protected and conserved. While many data objects were
published for general access via anonymous File Transfer Protocol (FTP), access to others required registration with
individual usernames and passwords.
Before widespread use of networks, viruses were the primary security concern for
most PC users. Virus infections spread from the early days of PCs, initially accompanying programs
shared on floppy disks and subsequently carried via communications facilities.
The Morris Worm
(1988) was the
first publicized example of a worm spreading via the Internet, and led to the
first conviction under the US Computer Fraud and Abuse Act. It exploited vulnerabilities present in
thousands of connected Unix systems, consuming their processing resources.