BREAKING THE
UNBREAKABLE
C
ryptography is used to send
classified information from
one party to another without
revealing it to an unintend-
ed third party. The word ‘Cryptography”
comes from the Greek words ‘kryptos’ and
‘graphein’ meaning ‘secret’ and ‘writing’.
First, the information that has to be hidden is transformed into an unreadable
format called cipher text. This text can
only be deciphered into plain text using
a secret key.
There are four main objectives of cryptography, namely; Confidentiality (the
information cannot be understood by
any other than the communicating parties), Integrity (the information cannot be
changed or tampered with during storage or transmission), Non-repudiation
(the sender of the information cannot
deny his intentions in the transfer of
Leon Battista Alberti, “The Father
of Western Cryptology”, introduced a
system in which
two copper disks
with the alphabet
inscribed in it were
used.
receiver whereas in public key encryption
two keys called the public key and the
private key are used. Here the public key
is known to all but the private key is kept
hidden. Encryption is done using the pub-
the information at a later stage) and
Authentication (the sender and the
receiver must be able to confirm the
identity of each other and the origin and
destination of the information).
Cryptanalysis or code-breaking is the
technique used to break encrypted messages. Mathematical theory and knowledge in computer science is essential in
code-breaking. There are two types of
cryptographic technologies; symmetric
encryption and public key encryption. In
symmetric encryption, the same key is
shared between both the sender and the
32
Gauge Newsletter
The Enigma Machine • Source: www.kusumatrust.gi
University of Peradeniya
lic key and encrypted text is decrypted by
the receiver using the private key.
Code- breaking is the art a