Transcript NEW 2-x IOT - Cryptography

COMMUNICATION TECHNOLOGY
October 21, 2010
Are you smarter than an extraterrestrial space alien?
"In the deepest sense the
search for extraterrestrial
intelligence is a search for
ourselves." - Carl Sagan
IOT
2-3
POLY ENGINEERING
As we go through
this lesson, you
should letter your
answers to these
questions.
IOT
2-3
POLY ENGINEERING
"In the deepest sense the search for extraterrestrial
intelligence is a search for ourselves." - Carl Sagan
IOT
2-3
POLY ENGINEERING
This is the radio telescope located at Arecibo, Puerto Rico.
The facility is a part of the NSF operated by Cornell University.
The Arecibo message was composed by Professors Frank
Drake and Carl Sagan of Cornell University. The message
was beamed into space a single time via frequency
modulated (FM) radio waves at a ceremony to mark the
remodeling of the Arecibo radio telescope on 16
November 1974. It was aimed at the star cluster M13
about 25,000 light years away. M13 is a large collection of
stars that was available in the sky at the time and place of
the ceremony. The message was transmitted at a
frequency of 2380 MHz and modulated by shifting the
frequency by 10 Hz, with a power of 1000 kW. The "ones"
and "zeroes" were transmitted by frequency shifting at
the rate of 10 bits per second. The total broadcast was
less than three minutes.
IOT
2-3
POLY ENGINEERING
Reminder from last week’s lessons:
Radio:
Encoder: Devices that convert sound and information into a
modulated sine wave
Pulse Modulation: turn the voltage (sine wave) on/off (Morse Code)
PM
Amplitude Modulation: vary the amplitude (peak-to-peak) voltage
AM
Frequency Modulation: vary the frequency (speed)
FM
IOT
2-2
POLY ENGINEERING
00000010101010000000000001010000010100000
00100100010001000100101100101010101010101
01001001000000000000000000000000000000000
00001100000000000000000001101000000000000
00000001101000000000000000000101010000000
00000000000111110000000000000000000000000
00000001100001110001100001100010000000000
00011001000011010001100011000011010111110
11111011111011111000000000000000000000000
00100000000000000000100000000000000000000
00000000100000000000000000111111000000000
00001111100000000000000000000000110000110
00011100011000100000001000000000100001101
00001100011100110101111101111101111101111
10000000000000000000000000010000001100000
00001000000000001100000000000000010000011
00000000001111110000011000000111110000000
00011000000000000010000000010000000010000
01000000110000000100000001100001100000010
00000000011000100001100000000000000011001
10000000000000110001000011000000000110000
11000000100000001000000100000000100000100
00000110000000010001000000001100000000100
01000000000100000001000001000000010000000
10000000100000000000011000000000110000000
01100000000010001110101100000000000100000
00100000000000000100000111110000000000001
00001011101001011011000000100111001001111
11101110000111000001101110000000001010000
01110110010000001010000011111100100000010
10000011000000100000110110000000000000000
00000000000000000001110000010000000000000
01110101000101010101010011100000000010101
01000000000000000010100000000000000111110
00000000000000011111111100000000000011100
00000111000000000110000000000011000000011
01000000000101100000110011000000011001100
00100010100000101000100001000100100010010
00100000000100010100010000000000001000010
00010000000000001000000000100000000000000
100101000000000001111001111101001111000
This is the binary code sent
from Arecibo observatory
on 16 November 1974.
?
IOT
2-3
POLY ENGINEERING
Cryptography (or cryptology; from Greek
κρυπτός, kryptos, "hidden, secret"; and
γράφω, gráphō, "I write", or -λογία, -logia,
respectively) is the practice and study of hiding
information. Modern cryptography intersects
the disciplines of mathematics, computer
science, and engineering. Applications of
cryptography include ATM cards, computer
passwords, and electronic commerce.
IOT
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POLY ENGINEERING
As a clue to decoding
the message, count the
number of “ones” and
the total number of
binary digits, “ones”
and “zeros”. Also
count the number of
rows and columns.
IOT
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POLY ENGINEERING
The binary digits form a
pattern of 41 columns by
41 rows, .. less two binary
digits at the end.
There are a total of
(41)(41) =1681 less 2 , or
1679 binary digits.
Of the 1679 binary digits,
there are 397 ‘ones’ and
1282 ‘zeros’.
There are two ways to
arrange the 1679 binary
digits as a pattern of rows
and column using prime
numbers: a pattern of 23
rows deep by 73 columns
wide, or a pattern of 73
rows deep by 23 columns
wide.
1679 is the product of two
prime numbers: 23 and 73.
397 is a prime number.
IOT
2-3
POLY ENGINEERING
There are two ways to arrange the 1679 binary digits as
a pattern of rows and column using prime numbers: a
pattern of 23 rows deep by 73 columns wide, or a
pattern of 73 rows deep by 23 columns wide.
IOT
2-3
POLY ENGINEERING
There are two
ways to
arrange the
1679 binary
digits as a
pattern of
rows and
column using
prime
numbers: a
pattern of 23
rows deep by
73 columns
wide, or a
pattern of 73
rows deep by
23 columns
wide.
You may now begin to
decode the message here
in class, and complete it at
home for homework.
IOT
2-3
POLY ENGINEERING
There are two
ways to
arrange the
1679 binary
digits as a
pattern of
rows and
column using
prime
numbers: a
pattern of 23
rows deep by
73 columns
wide, or a
pattern of 73
rows deep by
23 columns
wide.
The next slide shows the
decoded message.
IOT
2-3
POLY ENGINEERING
There are two
ways to
arrange the
1679 binary
digits as a
pattern of
rows and
column using
prime
numbers: a
pattern of 23
rows deep by
73 columns
wide, or a
pattern of 73
rows deep by
23 columns
wide.
IOT
2-3
POLY ENGINEERING
"Here is how we count from one to ten. Here
are five atoms that we think are interesting or
important: hydrogen, carbon, nitrogen, oxygen
and phosphorus. Here are some ways to put
these atoms together that we think interesting
or important - the molecules thymine, adenine,
guanine and cytosine, and a chain composed of
alternating sugars and phosphates. These
molecular building blocks are put together to
form a long molecule of DNA comprising about
four billion links in the chain. The molecule is a
double helix. In some way this molecule is
important for the clumsy looking creature at the
center of the message. That creature is 14 radio
wavelengths or 5 feet 9.5 inches tall. There are
about four billion of these creatures on the third
plant from our star. There are nine planets
altogether, four big ones toward the outside and
one little one at the extremity. This message is
brought to you courtesy of a radio telescope
2,430 wavelengths or 1,004 feet in diameter.
IOT
Yours truly."
2-3
POLY ENGINEERING