Wiretapping and
Encryption
More Week 5 cont.
Early Forms of
Wiretapping
Party Lines
Human Operators
Wiretapping Today
Federal and state law
enforcement
Businesses
Private Detectives
Political Candidates
......
Cellular Phones
Can be tapped with overthe-counter devices
Standard Phones
Easily tapped if signal
travels by microwave or
satellite
Government has secured
phones
Legal Mandates
 1937 - Supreme Court rules that
wiretapping is illegal
 1968 - Congress explicitly allowed
it by law enforcement agencies
 needs court order
 Electronic Communications Privacy
Act include new technologies
Cryptography - Making
and breaking of ciphers
 Translation of the original message
into a new incomprehensible one
by a mathematical algorithm using
a specific KEY
 Plaintext - a message or data
 Ciphertext - encrypted text
 Decryption - decipher back to
plaintext
Encryption Includes:
Coding scheme or
cryptographic algorithm
Specific sequence of
characters key used by the
algorithm
Examples
Cereal box codes
Substitute cipher
Cryptoquip in newspaper
Variations - Symmetric
Use the same key to
encrypt and decrypt
(secret key)
Requires a more secure
system to send the key
than the system itself
Variation - Asymmetric
Use a key (public key) to
encrypt a message
Another (private key) to
decrypt it
Requires both keys
Who Uses Encryption?
Banks
Industry
Professionals
National ID cards
Criminals
Government
.....
Industrial Espionage
Knowledge of a company’s
cost and price structure
Market research
Strategic plans
Order and customer lists
Insider information
Professionals
Cellular telephones and
electronic mail
unencrypted data on
machines
Criminals
 Cryptography allows criminals
to keep their identities a
secret
 Provides security to law
breakers
 Allows anonymity
 Don’t use systems that leave
trails
Reliability
 The longer the key has remained
unbroken, the stronger it is likely
to be
 The longer the key is in use, the
more likely someone will be able to
discover it
 larger amount of info will be
compromised
 change key frequently
Algorithms available
 DES - Data Encryption Standard
 Developed by IBM in the 1970’s
 Adopted as a Federal Information
Processing Standard
 Uses a 56 bit key
 Has been broken
 To extend life - extend key to 128 bits
 or triple DES
RSA algorithm
Used in public key
cryptography
Patented in US
Based on multiplication of
large prime numbers
PGP - Pretty Good Privacy
Based on RSA
Used for protecting E-Mail
New Controversies
 1991 - Senate Bill Government wants to be able
to intercept any message and
be able to decode it as well not passed
 FBI and wiretapping Telephony bills
 FBI and Clipper Chip
Benefits of Government
Intervention
Aid law enforcement in
protecting us from
criminals and terrorists
Problems
Threats to
 privacy
 global competitiveness
 civil liberties
Communications
Assistance for Law
Enforcement Act 1994
 to and from Requires that
telecommunications equipment be
designed so govt. can:
 intercept all wire and electronic
communic.
 Intercept comms from mobile users
 Obtain call-identifying info
phone numbers
 Have info transmitted to a specific
location
 Government will help foot the bill
Arguments for...
 Protection from terrorists and criminals
 FBI wants no new privileges
 BUT
 Necessity has not been justified
 Expense and other problems
outweigh the benefits
 There has never been a guarantee of
interception of private messages
before
NEED?
 Wiretaps are less useful than informants,
witnesses, etc.
 BUT
 90% of terrorist cases used wiretaps
 Industry claims full compliance with FBI
 BUT
 Continued cooperation is not
guaranteed
COST?
 A lot more than government is
giving
 Will save money in
 fines, forfeitures, prevented
economic loss
 Used only in a subset of
investigations
 Could use the money on other
technologies
Innovation and global
competitiveness
 Stifle or delay new
technologies
 economic costs
 prevent new technologies’
implementation
 Damage to US competitiveness
in global markets due to
reduced security and privacy
Protection from Dossier
Society
Digital cash made possible
by public key encryption
Secure financial
transactions without a
credit card or checking
account number
E-Cash







No link between payer and recipient
Convenience of credit card
Anonymity of cash
Use on Internet for ordinary shopping
Can transfer credentials
Can prevent duplicate cash files
Back up at home in case card is lost or
stolen
E-Cash continued
Not easy to form a
consumer profile or dossier
Prevent fraud and forgery
Protect privacy from
mailing lists
More control over personal
information
History of Encryption
 Secret - NSA
 National Security Agency
 can do anything
 has powerful computers - break
ciphers and create ciphers
 monitors all communications
between US and other countries
Government Interception
 NSA censored research
 controlled researchers
 Export restrictions
munitions
can’t export secure
systems