Surveillance or Security?: The Risks Posed by New Wiretapping Technologies by Susan Landau
Authors: Susan Landau
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busy now. Please try your call again later." Yet
another distinction is that Internet users do not necessarily know the IP
address of the person they wish to "call" using VoIP. Because the Internet
enables mobility, there is no "phone book" of IP addresses, which are often
allocated dynamically. The user can have a different IP address each time
they log on. In the space of an hour, the caller can move from a hotel
lobby to a cafe to an airport lounge. Most VoIP systems use a rendezvous
service that transforms a user identifier (e.g., a telephone number, screen
name, email address) into the user's current IP address."
2.7 Data on the Voice Network
While the Internet has enabled voice communications over what was
originally a data network, the telephone network has gone the other way: simplifying text transmission over a voice network. This is texting, also
called SMS.61 Texting arose from telephone signaling capabilities developed
in the 1980s. Once call setup information traveled on the same channel
as voice communications, but as communications systems moved to digital
transmission, an out-of-band channel was needed for transmitting the
signaling information. Thus Signaling System 6 (SS6), a packet-based digital
protocol for network control, was developed in the 1970s; it has since been
replaced by Signaling System 7 (SS7), which is more versatile. SS7 uses two
conduits: a Call Content Channel (CCC) that is typically, though not necessarily, used for voice communications, and a separate call signaling channel,
the Call Data Channel (CDC). This architecture enables such advanced
telephony features as caller ID, call forwarding, and voice mail.
When the CDC is not in use, it could be put to other purposes. One
such is enabling the transmission of short text messages between users;
that is the essence of SMS.62 SMS lets users send 140-character-long messages from the keypad of their cell phones.63 It was introduced by European
commercial carriers in 1993. The carriers did not use the same standard
for texting, and originally text messages could not be sent between networks. Once that issue was resolved, texting took off. By 2003, over 70
percent of Europeans were using text messaging.64 The telecommunications companies expected businesspeople to be the SMS users, but the
biggest market for SMS turned out to be teenagers, a pattern echoed in
other parts of the world.
Texting is popular in Asia, where adoption of personal computers lags far
behind that of western Europe and the United States,65 and the cell phone
is the communications device of choice. One in three Chinese has a mobile
phone, and China is responsible for over 300 billion SMS communications
annually. The Asia-Pacific region and Japan sent an estimated 1.5 trillion
messages in 2007,66 and that number is only expected to grow. Everyoneteenagers, families, businesspeople, commuters-uses text messaging. Japan
was an early leader in texting. Japan's use is far broader than simple messages: five of 2007's bestselling novels were originally published via cell
phones.67 Japan's texting technology is, however, different from most other
nations': it is IP-based rather than using cell phone technology.
Texting can be used for fun and games, but it is also used for business.
That is its primary purpose in Africa. On a continent where transport and
wired communications are unreliable, SMS technology is a true business
enabler.68 As is the case throughout the world, the asynchrony of text
messaging is part of its attractiveness as a communications medium. Sometimes texting can be used for serious political business. In 2001, Philippine President Joseph Estrada was ousted after hundreds of thousands of people,
summoned to the streets by text messages, protested a vote that would
have cleared the president of wrongdoing.69 Even China, which carefully
controls communication channels and political activities, has had political
another distinction is that Internet users do not necessarily know the IP
address of the person they wish to "call" using VoIP. Because the Internet
enables mobility, there is no "phone book" of IP addresses, which are often
allocated dynamically. The user can have a different IP address each time
they log on. In the space of an hour, the caller can move from a hotel
lobby to a cafe to an airport lounge. Most VoIP systems use a rendezvous
service that transforms a user identifier (e.g., a telephone number, screen
name, email address) into the user's current IP address."
2.7 Data on the Voice Network
While the Internet has enabled voice communications over what was
originally a data network, the telephone network has gone the other way: simplifying text transmission over a voice network. This is texting, also
called SMS.61 Texting arose from telephone signaling capabilities developed
in the 1980s. Once call setup information traveled on the same channel
as voice communications, but as communications systems moved to digital
transmission, an out-of-band channel was needed for transmitting the
signaling information. Thus Signaling System 6 (SS6), a packet-based digital
protocol for network control, was developed in the 1970s; it has since been
replaced by Signaling System 7 (SS7), which is more versatile. SS7 uses two
conduits: a Call Content Channel (CCC) that is typically, though not necessarily, used for voice communications, and a separate call signaling channel,
the Call Data Channel (CDC). This architecture enables such advanced
telephony features as caller ID, call forwarding, and voice mail.
When the CDC is not in use, it could be put to other purposes. One
such is enabling the transmission of short text messages between users;
that is the essence of SMS.62 SMS lets users send 140-character-long messages from the keypad of their cell phones.63 It was introduced by European
commercial carriers in 1993. The carriers did not use the same standard
for texting, and originally text messages could not be sent between networks. Once that issue was resolved, texting took off. By 2003, over 70
percent of Europeans were using text messaging.64 The telecommunications companies expected businesspeople to be the SMS users, but the
biggest market for SMS turned out to be teenagers, a pattern echoed in
other parts of the world.
Texting is popular in Asia, where adoption of personal computers lags far
behind that of western Europe and the United States,65 and the cell phone
is the communications device of choice. One in three Chinese has a mobile
phone, and China is responsible for over 300 billion SMS communications
annually. The Asia-Pacific region and Japan sent an estimated 1.5 trillion
messages in 2007,66 and that number is only expected to grow. Everyoneteenagers, families, businesspeople, commuters-uses text messaging. Japan
was an early leader in texting. Japan's use is far broader than simple messages: five of 2007's bestselling novels were originally published via cell
phones.67 Japan's texting technology is, however, different from most other
nations': it is IP-based rather than using cell phone technology.
Texting can be used for fun and games, but it is also used for business.
That is its primary purpose in Africa. On a continent where transport and
wired communications are unreliable, SMS technology is a true business
enabler.68 As is the case throughout the world, the asynchrony of text
messaging is part of its attractiveness as a communications medium. Sometimes texting can be used for serious political business. In 2001, Philippine President Joseph Estrada was ousted after hundreds of thousands of people,
summoned to the streets by text messages, protested a vote that would
have cleared the president of wrongdoing.69 Even China, which carefully
controls communication channels and political activities, has had political
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