24-04-2012, 01:58 PM
cryptography full report
Cryptography.doc (Size: 83 KB / Downloads: 54)
Introduction:
Cryptography in greek means: kryptos – “secret”; graphos – “writing”. It is an art and science of preparing coded or protected communications. The enciphering process usually involves an algorithm and a key. An encryption algorithm is a particular method of scrambling—a computer program or a written set of instructions. The key specifies the actual scrambling process. The original communication may be a written or broadcast message or a set of digital data.
One essential aspect for secure communications is that of cryptography, which is the focus of this presentation. But it is important to note that while cryptography is necessary for secure communications, it is not by itself sufficient.
This paper has two major purposes. The first is to define some of the terms and concepts behind basic cryptographic methods, and to offer a way to compare the myriad cryptographic schemes in use today. The second is to illustrate the significance of RSA and DES algorithms. Today, cryptography is a way of life, right from operating systems to SMART cards, the entire DIGITAL SECURITY is based on cryptography,
History
The first documented use of cryptography in writing dates back to circa 1900 B.C. when an Egyptian scribe used non-standard hieroglyphs in an inscription. Some experts argue that cryptography appeared spontaneously sometime after writing was invented, with applications ranging from diplomatic missives to war-time battle plans.
A more recent example can be seen during WORLD WAR - 1 :
Before the United States entered World War I, the German government tried to provoke a war between the United States and Mexico. On January 19, 1917, the German foreign secretary, Arthur Zimmermann, sent an encoded telegram to his diplomatic representatives in Mexico, asking them to propose a secret alliance with the Mexican government. But British intelligence officers intercepted and quickly decoded the message, sending it on to President Woodrow Wilson. A huge public outcry ultimately resulted in an American declaration of war against Germany.
It is no surprise, then, that new forms of cryptography came soon after the widespread development of computer communications.
The purpose of Cryptography
In data and telecommunications, cryptography is necessary when communicating over any untrusted medium, which includes just about any network, particularly the Internet.
Within the context of any application-to-application communication, there are some specific security requirements, including:
Authentication: The process of proving one's identity. (The primary forms of host-to-host authentication on the Internet today are name-based or address-based, both of which are notoriously weak.)
Privacy/confidentiality: Ensuring that no one can read the message except the intended receiver.
Integrity: Assuring the receiver that the received message has not been altered in any way from the original.
Non-repudiation: A mechanism to prove that the sender really sent this message.
As,stated above PRIVACY and authentication are of utmost importance today, due to the presence of innumerable HACKERS, and due to the fact that the entire world is becoming a global village .Thanks to the technology , today right from bank transactions to matrimony all take place in a fraction of a second with the help of internet.
Cryptography, then, not only protects data from theft or alteration, but can also be used for user authentication, without which the entire computer community would collapse.
Types of Cryptography algorithms
There are several ways of classifying cryptographic algorithms. For purposes of this paper, they will be categorized based on the number of keys that are employed for encryption and decryption, and further defined by their application and use.
Steganography:
It is the art and science of writing hidden messages in such a way that no one apart from the intended recipient knows of the existence of the message; this is in contrast to cryptography, where the existence of the message itself is not disguised, but the content is obscured It is a method of hiding the existence of a message using tools such as invisible ink, microscopic writing, or hiding code words within sentences of a message (such as making every fifth word in a text part of the message). Cryptographers may apply steganography to electronic communications. This application is called transmission security.Generally, a steganographic message will appear to be something else: a picture, an article, a shopping list, or some other message - the covertext. Classically, it may be hidden by using invisible ink between the visible lines of innocuous documents, or even written onto clothing .
Cryptography.doc (Size: 83 KB / Downloads: 54)
Introduction:
Cryptography in greek means: kryptos – “secret”; graphos – “writing”. It is an art and science of preparing coded or protected communications. The enciphering process usually involves an algorithm and a key. An encryption algorithm is a particular method of scrambling—a computer program or a written set of instructions. The key specifies the actual scrambling process. The original communication may be a written or broadcast message or a set of digital data.
One essential aspect for secure communications is that of cryptography, which is the focus of this presentation. But it is important to note that while cryptography is necessary for secure communications, it is not by itself sufficient.
This paper has two major purposes. The first is to define some of the terms and concepts behind basic cryptographic methods, and to offer a way to compare the myriad cryptographic schemes in use today. The second is to illustrate the significance of RSA and DES algorithms. Today, cryptography is a way of life, right from operating systems to SMART cards, the entire DIGITAL SECURITY is based on cryptography,
History
The first documented use of cryptography in writing dates back to circa 1900 B.C. when an Egyptian scribe used non-standard hieroglyphs in an inscription. Some experts argue that cryptography appeared spontaneously sometime after writing was invented, with applications ranging from diplomatic missives to war-time battle plans.
A more recent example can be seen during WORLD WAR - 1 :
Before the United States entered World War I, the German government tried to provoke a war between the United States and Mexico. On January 19, 1917, the German foreign secretary, Arthur Zimmermann, sent an encoded telegram to his diplomatic representatives in Mexico, asking them to propose a secret alliance with the Mexican government. But British intelligence officers intercepted and quickly decoded the message, sending it on to President Woodrow Wilson. A huge public outcry ultimately resulted in an American declaration of war against Germany.
It is no surprise, then, that new forms of cryptography came soon after the widespread development of computer communications.
The purpose of Cryptography
In data and telecommunications, cryptography is necessary when communicating over any untrusted medium, which includes just about any network, particularly the Internet.
Within the context of any application-to-application communication, there are some specific security requirements, including:
Authentication: The process of proving one's identity. (The primary forms of host-to-host authentication on the Internet today are name-based or address-based, both of which are notoriously weak.)
Privacy/confidentiality: Ensuring that no one can read the message except the intended receiver.
Integrity: Assuring the receiver that the received message has not been altered in any way from the original.
Non-repudiation: A mechanism to prove that the sender really sent this message.
As,stated above PRIVACY and authentication are of utmost importance today, due to the presence of innumerable HACKERS, and due to the fact that the entire world is becoming a global village .Thanks to the technology , today right from bank transactions to matrimony all take place in a fraction of a second with the help of internet.
Cryptography, then, not only protects data from theft or alteration, but can also be used for user authentication, without which the entire computer community would collapse.
Types of Cryptography algorithms
There are several ways of classifying cryptographic algorithms. For purposes of this paper, they will be categorized based on the number of keys that are employed for encryption and decryption, and further defined by their application and use.
Steganography:
It is the art and science of writing hidden messages in such a way that no one apart from the intended recipient knows of the existence of the message; this is in contrast to cryptography, where the existence of the message itself is not disguised, but the content is obscured It is a method of hiding the existence of a message using tools such as invisible ink, microscopic writing, or hiding code words within sentences of a message (such as making every fifth word in a text part of the message). Cryptographers may apply steganography to electronic communications. This application is called transmission security.Generally, a steganographic message will appear to be something else: a picture, an article, a shopping list, or some other message - the covertext. Classically, it may be hidden by using invisible ink between the visible lines of innocuous documents, or even written onto clothing .