The only interesting point is that in the ?¬?rst line
the browser asks the Web server for the document it needs.
If everything goes as planned, the Web server locates the document
and serves it back to the browser. The text shown in Figure
1-9 is the reply that the Web server sends back to the browser.
HTTP is the main
protocol through
which most interactions
on the Internet
take place
Figure 1-8 An HTTP GET request
48 The Problem
Again, the details of the text are not important. What is interesting
to note is that the Web server, after a few lines of HTTP
mumbo jumbo, writes the Hypertext Markup Language (HTML)
content of the page requested by Alice in clear text. The browser
reads the received HTML and renders it as the page depicted in
Figure 1-10.
Figure 1-9 An HTTP response
Figure 1-10 The browser renders the HTML.
The Babel of Cryptography 49
Apparently, Bob will show his real page only to authenticated
users. Alice ?¬?lls her credentials in the ?¬?elds provided and clicks
the Submit button. The browser will diligently use HTTP for
sending information back to the Web server. The network traf?¬?c
generated will look like the text in Figure 1-11.
The remarkable point here is Alice??™s credentials are perfectly
readable by anyoneon the path between her computer and
Bob??™s Web server.
Pages:
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103