From Simple English Wikipedia, the free encyclopedia
A
code
is a way of changing information into something else. Sometimes this is done as a way of keeping a message
secret
. This is called
encryption
or
cryptography
.
[1]
One source gives this explanation: a code is "a word, number or some other symbol used to represent a word,
phrase
or
syllable
in
plaintext
".
[2]
It is one of the earliest forms of
cryptography
. Contrast code with
cypher
, in which the individual letters are encrypted (changed).
Sometimes it is done as an easier way of sending a message. For example, when people on two different boats want to send a message, they may be too far away to shout, but they can send messages with a flag code. Another code that people use is called
Morse code
, which changes letters to dots and dashes, like this:
SOS
:
···???···
Computers use codes, by changing letters into 1's and 0's. This method was invented for
punched tape
. Now the usual alphanumeric code is
ASCII
.
Some people write codes as a kind of
game
. They think it is fun to make ciphers, and fun to break them. Breaking a code means taking it apart to understand how it works, and then you can understand messages that are written in that code.
Cryptanalysis
is also serious business. Nations and other organizations have been breaking each other's ciphers for many centuries.
The
algorithm
(code) for making a message secret is called the
encryption
algorithm. To change a secret message back a
decryption
algorithm is needed.
- ↑
Kahn, David 1967.
The Codebreakers ? the story of secret writing
.
ISBN
0-684-83130-9
- ↑
Newton, David E. 1997.
Encyclopedia of cryptology
. Instructional Horizons, Santa Barbara, p58.
ISBN
1-85109-323-0