OVERVIEW OF CRYPTOGRAPHY AND TODAY’S ENCRYPTION
M.SAFANA YASMIN MSC(COMPUTER SCIENCE)
Abstract 2,500 years. Cryptography was used
This paper presents a detailed study of in the form of ‘substitution ciphers’ in
asymmetric and symmetric encryption the reign of Julius Caesar. In that
and decryption algorithms by encryption, each letter was replaced
focusing on the operations, the by three other letters.
strengths, and weaknesses of the RSA In the nineteenth century, it started
and Data Encryption Standard (DES) with a traditional aim of securing
algorithms. The best characteristics of governments and the military. At that
DES and RSA algorithms can be time, i.e., prior to the 1970s,
combined to form a hybrid encryption cryptography was only practiced by
algorithm to provide the desired the government and military
properties of message integrity, personnel; however, later, it spread in
authentication, and non-repudiation. the public sector. Piper & Murphy
This improves the security of (2002) has also mentioned
information as anyone having the cryptography of the 1970s as a ‘black
public key can only encrypt the art’ only accessible by the
message but not decrypt it government.
In a traditional context, its popularity
Cryptography and increase in public awareness lead
According to Curtin (2007), the museums and places of historic
cryptography is the study of the interest to discover their origin.
mathematical methods used to Therefore the museums started
develop algorithms which are used for exhibiting the old cipher machines.
secret writing to enforce message Later, when media started exposing
authentication, integrity, and cryptography as a means for
confidentiality. providing security, many films on the
Cryptography enables the detection Second World War stressed the
and prevention of cheating and importance of code-breaking.
malicious activities (Akl & Taylor, However, films like Pearl Harbor
1993). explained the impact of the breaking
of encrypted messages.
History With the passage of time,
Cryptography or encrypting the cryptography was made available to
message is just like a letter, which at all sectors of society. Two forces that
the time of posting is sealed in the influenced this transition of awareness
envelope. Piper & Murphy (2002) were ‘business’ and ‘Internet,’ and
Cryptography is a well-established both, when combined, gave rise to
science that has been a significant ‘online’ companies. With the advent
historical influence for more than of online business, the concept of ‘e-
1
, OVERVIEW OF CRYPTOGRAPHY AND TODAY’S ENCRYPTION
M.SAFANA YASMIN MSC(COMPUTER SCIENCE)
commerce’ gradually appeared, Figure 1
thereby creating awareness on the
customer level. Governments who
once adopted ‘cryptography’ while
communicating with their militants
now started communicating with their
citizens via the Internet. These were,
on the one hand, provided
opportunities; on the other created The figure above illustrates the public
concerns which involved security at and private cryptosystem which is
every level like ‘taxation,’ ‘illegal used to achieve message encryption,
transaction,’ etc. So, in order to deal decryption, integrity, authentication,
with such issues, there emerged a non-repudiation, and confidentiality
need to advance cryptography. (Curtin, 2007).
Symmetric
Bellovin and Merritt (1992) argues
that a symmetric algorithm uses one
secret key to encrypt plaintext into
ciphertext and to decrypt ciphertext
into plaintext.
The advantage with the symmetric
algorithm is that it consumes fewer
resources than its asymmetric
counterpart. The main challenge with
symmetric algorithms is to keep the
key secret. However, if the key is
known to the attacker, the
communication becomes unsafe
(Curtin, 2007).
Encryption
Encryption is a process that uses an
encryption algorithm to convert a
message from plaintext into
ciphertext, making the message
unreadable to a third party (Akl & Asymmetric
Taylor, 1993). Figure 1 below shows An asymmetric encryption algorithm
a cryptographic system used to uses a public key to encrypt a
encrypt and decrypt messages. message and a private key to decrypt
the message (Curtin, 2007). The
2
M.SAFANA YASMIN MSC(COMPUTER SCIENCE)
Abstract 2,500 years. Cryptography was used
This paper presents a detailed study of in the form of ‘substitution ciphers’ in
asymmetric and symmetric encryption the reign of Julius Caesar. In that
and decryption algorithms by encryption, each letter was replaced
focusing on the operations, the by three other letters.
strengths, and weaknesses of the RSA In the nineteenth century, it started
and Data Encryption Standard (DES) with a traditional aim of securing
algorithms. The best characteristics of governments and the military. At that
DES and RSA algorithms can be time, i.e., prior to the 1970s,
combined to form a hybrid encryption cryptography was only practiced by
algorithm to provide the desired the government and military
properties of message integrity, personnel; however, later, it spread in
authentication, and non-repudiation. the public sector. Piper & Murphy
This improves the security of (2002) has also mentioned
information as anyone having the cryptography of the 1970s as a ‘black
public key can only encrypt the art’ only accessible by the
message but not decrypt it government.
In a traditional context, its popularity
Cryptography and increase in public awareness lead
According to Curtin (2007), the museums and places of historic
cryptography is the study of the interest to discover their origin.
mathematical methods used to Therefore the museums started
develop algorithms which are used for exhibiting the old cipher machines.
secret writing to enforce message Later, when media started exposing
authentication, integrity, and cryptography as a means for
confidentiality. providing security, many films on the
Cryptography enables the detection Second World War stressed the
and prevention of cheating and importance of code-breaking.
malicious activities (Akl & Taylor, However, films like Pearl Harbor
1993). explained the impact of the breaking
of encrypted messages.
History With the passage of time,
Cryptography or encrypting the cryptography was made available to
message is just like a letter, which at all sectors of society. Two forces that
the time of posting is sealed in the influenced this transition of awareness
envelope. Piper & Murphy (2002) were ‘business’ and ‘Internet,’ and
Cryptography is a well-established both, when combined, gave rise to
science that has been a significant ‘online’ companies. With the advent
historical influence for more than of online business, the concept of ‘e-
1
, OVERVIEW OF CRYPTOGRAPHY AND TODAY’S ENCRYPTION
M.SAFANA YASMIN MSC(COMPUTER SCIENCE)
commerce’ gradually appeared, Figure 1
thereby creating awareness on the
customer level. Governments who
once adopted ‘cryptography’ while
communicating with their militants
now started communicating with their
citizens via the Internet. These were,
on the one hand, provided
opportunities; on the other created The figure above illustrates the public
concerns which involved security at and private cryptosystem which is
every level like ‘taxation,’ ‘illegal used to achieve message encryption,
transaction,’ etc. So, in order to deal decryption, integrity, authentication,
with such issues, there emerged a non-repudiation, and confidentiality
need to advance cryptography. (Curtin, 2007).
Symmetric
Bellovin and Merritt (1992) argues
that a symmetric algorithm uses one
secret key to encrypt plaintext into
ciphertext and to decrypt ciphertext
into plaintext.
The advantage with the symmetric
algorithm is that it consumes fewer
resources than its asymmetric
counterpart. The main challenge with
symmetric algorithms is to keep the
key secret. However, if the key is
known to the attacker, the
communication becomes unsafe
(Curtin, 2007).
Encryption
Encryption is a process that uses an
encryption algorithm to convert a
message from plaintext into
ciphertext, making the message
unreadable to a third party (Akl & Asymmetric
Taylor, 1993). Figure 1 below shows An asymmetric encryption algorithm
a cryptographic system used to uses a public key to encrypt a
encrypt and decrypt messages. message and a private key to decrypt
the message (Curtin, 2007). The
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