Anyone with a moderate amount of skill can intercept Internet mail
messages and private web pages to see what they say; can modify
messages in transit, changing their content without any trace; and
can send fake messages that are indistinguishable from legitimate
messages. Cryptography responds to these threats by scrambling and
unscrambling packets to protect against forgery and against
espionage. An attacker who forges a message can't scramble it in the
right way; when legitimate users' computers unscramble the message,
they see that it's a forgery and that it should be thrown away. An
attacker who intercepts a scrambled credit-card number can't figure
out the original number.
Unfortunately, cryptography is often too slow to deploy on busy
network servers. Widely used web sites such as google.com and
livejournal.com have installed all the necessary cryptographic
software but use it for only a small fraction of their web pages.
When a user tells his web browser to make a cryptographically
protected connection to www.google.com, Google redirects the
browser to www.google.com, turning off the cryptography!
Similar comments apply to SMTP (mail), DNS (name lookup), and other
Internet protocols: even when the necessary cryptographic software
has been written and installed, users are often forced to disable or
limit the software so that their computers are not overloaded. This
research responds by producing new speed records for the
cryptographic operations needed to protect the Internet. These
speedups allow cryptography to handle a larger fraction of the total
volume of Internet communication, reducing the Internet's overall
exposure to attack.
